Zinc supplementation may help treat anorexia nervosa, ADHD, and treatment-resistant depression.
Zinc is a metallic element involved in multiple aspects of human cellular function, metabolism, growth, and immune function. It is required for the function of about 100 human enzymes. The human body contains about 2000-3000 mg of zinc, of which about 2-3 mg are lost daily through kidneys, bowel, and sweat glands. The biologic half-life of zinc in the body is about 9 months, so it can take months or years for changes in dietary habits to substantially change zinc status, unless the intake is very high for short periods.
Red meat is a particularly rich source of zinc. Vegetarians may have a harder time getting an adequate amount from the diet. The prevalence of zinc deficiency may be as high as 40% worldwide.
When referring to zinc dosage, it is best to refer to "elemental zinc". Different types of zinc preparations (e.g. zinc gluconate or zinc sulphate) have different amounts of elemental zinc. For example, 100 mg of zinc gluconate contains about 14 mg of elemental zinc. 110 mg of zinc sulphate contains about 25 mg of elemental zinc.
Here are references to articles written by a Vancouver eating disorders specialist between 1994 and 2006, advising supplementation of 14 mg elemental zinc daily (corresponding to 100 mg zinc gluconate daily) for 2 months in all anorexic patients:
http://www.ncbi.nlm.nih.gov/pubmed/17272939
http://www.ncbi.nlm.nih.gov/pubmed/11930982
http://www.ncbi.nlm.nih.gov/pubmed/8199605
Here's a 1987 article from a pediatrics journal, showing improvement in depression and anxiety following 50 mg/d elemental zinc supplementation in anorexic adolescents:
http://www.ncbi.nlm.nih.gov/pubmed/3312133
In this 1990 open study, anorexic patients were treated with 45-90 mg elemental zinc daily, most of whom had significant improvement in their eating disorder symptoms over 2 years of follow-up.
http://www.ncbi.nlm.nih.gov/pubmed/2291418
Here's a 1992 case report of substantial improvement in severe anorexia following zinc supplementation:
http://www.ncbi.nlm.nih.gov/pubmed/1526438
Zinc depletion may lead to an abnormal sense of taste (hypogeusia or dysgeusia). This sensory abnormality improves with zinc supplementation. Here's a reference:
http://www.ncbi.nlm.nih.gov/pubmed/8835055
Here's a randomized , controlled 2009 Turkish study showing that 10 weeks of 15 mg/day zinc supplementation led to improvement in ADHD symptoms in children. However, a close look at the study shows a bizarre lack of statistical analysis comparing the supplemented group directly with the placebo group. When you look at the data from the article, both groups improved to a modest degree on most measures, with perhaps a little bit more improvement in the zinc group. The analysis here was insufficient, I'm surprised a journal would accept this.
http://www.ncbi.nlm.nih.gov/pubmed/19133873
Here's a 2004 reference to a study showing that 6 weeks of 15 mg elemental zinc daily as an adjunct to stimulant therapy improved ADHD symptoms in children, compared to stimulant therapy plus placebo. In this case, there was a valid statistical analysis:
http://www.ncbi.nlm.nih.gov/pubmed/15070418
Here's a 2009 study showing that zinc supplementation improves the response to antidepressants in treatment-resistant depression. The dose they used was 25 mg elemental zinc daily, over 12 weeks.
http://www.ncbi.nlm.nih.gov/pubmed/19278731
Here's an excellent 2008 review article about zinc deficiency, and about the potential role of zinc supplementation in a wide variety of diseases (e.g. infections ranging from the common cold, to TB, to warts; arthritis; diarrhea; mouth ulcers). The review shows that zinc may have benefit for some of these conditions, but the evidence is a bit inconsistent:
http://www.ncbi.nlm.nih.gov/pubmed/18221847
Here is a warning about zinc toxicity:
http://www.ncbi.nlm.nih.gov/pubmed/12368702 {hematological toxicity from taking 50-300 mg zinc daily for 6-7 months. The toxicity was thought to be due to zinc-induced copper malabsorption leading to sideroblastic anemia}
Here is a nice website from NIH summarizing the role of zinc in the diet, in the body, some of the research about health effects, and about toxicity. It sticks to a recommended daily intake of 10-15 mg elemental zinc for adults, or about 5 mg for young children. It states that the maximum tolerable daily intake levels are about 5-10 mg for young children, 20-30 mg for adolescents, and 40 mg daily for adults:
http://ods.od.nih.gov/FactSheets/Zinc.asp
Here is a reference to another excellent review of zinc requirements, benefits, and risks. It makes more cautious recommendations about zinc supplementation, advising no more than 20 mg/day of zinc intake in adults. In order to prevent copper deficiency, it also advises that that the ratio between zinc intake and copper intake does not exceed 10.
http://www.ncbi.nlm.nih.gov/pubmed/16632171
So, were I to make a recommendation about a zinc supplementation trial, I would advise sticking to amounts under 20 mg (elemental) per day for adults, and to ensure that you are getting 2 mg of copper per day with that.
Showing posts with label Nutrition. Show all posts
Showing posts with label Nutrition. Show all posts
Wednesday, July 15, 2009
Friday, June 12, 2009
Herbal Supplements & Vitamins
I'm starting a series of posts based on some questions that were sent in by a visitor (A.E.).
Here's the first question:
1. Herbal supplements and vitamins: What are your views on therapeutic value of multivitamins, Valerian, Kava, Inositol, Passion Flower, and so on?
-I think the risk:benefit ratio of multivitamins is quite favorable. I've written a few other posts about vitamins. With respect to mood or brain function in general, there may be particular benefit from folic acid, thiamine, and higher doses of vitamin D. Standard dose vitamin-mineral supplements are probably harmless at worst (as long as you get a good-quality brand--there's some evidence of dangerous impurities such as lead, in some ). Many people have poor diets, and a supplement could at least help prevent deficiencies in vitamins and iron which may further obstruct recovery from mental health problems. Supplements should not be a substitute for improving the healthiness of one's overall diet (you still need to eat your vegetables even if you're taking vitamins!)
Selling supplements is a huge business: the world market has about $180 billion of annual sales, and is rapidly growing (reference: http://www.nutraceuticalsworld.com/articles/2008/04/dietary-supplements-the-latest-trends-issues).
This is comparable in size to the $440 billion annual market size of the pharmaceutical industry (reference: http://www.valuenotes.com/Prabhudas/pl_pharma_31Mar09.asp?ArtCd=143465&Cat=I&Id=12).
I think we need to be wary of the sales tactics that go on in the dietary supplement business, especially since the quality of research in this area is, for the most part, quite primitive. If you walk into the nutritional supplement area of a health food store or pharmacy, you may be bombarded with advertising, possibly a sales person offering you attention, concern, and apparent expertise--and all of this is in the context of all sorts of other obviously healthy things, perhaps organic vegetables, right next to you. It is a biased environment. Proximity to healthy food and healthy people does not constitute evidence of effectiveness! Yet, there are some supplements that could be helpful. Just be wary of the hype, pseudo-scientific claims, and sales jargon, etc.
I'll write separate posts about valerian, kava, passion flower, and inositol.
In the meantime, here's a reference to a 2006 review in The British Journal of Psychiatry about complementary medicines in psychiatry. I recommend having a look at the whole article at a library:
http://www.ncbi.nlm.nih.gov/pubmed/16449696
Here's the first question:
1. Herbal supplements and vitamins: What are your views on therapeutic value of multivitamins, Valerian, Kava, Inositol, Passion Flower, and so on?
-I think the risk:benefit ratio of multivitamins is quite favorable. I've written a few other posts about vitamins. With respect to mood or brain function in general, there may be particular benefit from folic acid, thiamine, and higher doses of vitamin D. Standard dose vitamin-mineral supplements are probably harmless at worst (as long as you get a good-quality brand--there's some evidence of dangerous impurities such as lead, in some ). Many people have poor diets, and a supplement could at least help prevent deficiencies in vitamins and iron which may further obstruct recovery from mental health problems. Supplements should not be a substitute for improving the healthiness of one's overall diet (you still need to eat your vegetables even if you're taking vitamins!)
Selling supplements is a huge business: the world market has about $180 billion of annual sales, and is rapidly growing (reference: http://www.nutraceuticalsworld.com/articles/2008/04/dietary-supplements-the-latest-trends-issues).
This is comparable in size to the $440 billion annual market size of the pharmaceutical industry (reference: http://www.valuenotes.com/Prabhudas/pl_pharma_31Mar09.asp?ArtCd=143465&Cat=I&Id=12).
I think we need to be wary of the sales tactics that go on in the dietary supplement business, especially since the quality of research in this area is, for the most part, quite primitive. If you walk into the nutritional supplement area of a health food store or pharmacy, you may be bombarded with advertising, possibly a sales person offering you attention, concern, and apparent expertise--and all of this is in the context of all sorts of other obviously healthy things, perhaps organic vegetables, right next to you. It is a biased environment. Proximity to healthy food and healthy people does not constitute evidence of effectiveness! Yet, there are some supplements that could be helpful. Just be wary of the hype, pseudo-scientific claims, and sales jargon, etc.
I'll write separate posts about valerian, kava, passion flower, and inositol.
In the meantime, here's a reference to a 2006 review in The British Journal of Psychiatry about complementary medicines in psychiatry. I recommend having a look at the whole article at a library:
http://www.ncbi.nlm.nih.gov/pubmed/16449696
Thursday, April 30, 2009
Dietary Fat and Mood
Dietary fat is necessary for mental and physical health. Excessively lean diets may be mentally and physically unhealthy. A balanced diet, with abundant fruits and vegetables, at least 30% of calories coming from fat, and with carbohydrates coming from foods with a lower glycemic index (e.g. reducing amounts of simple sugars), is probably a sound recommendation for good physical and mental health.
The type of fat is important, though: trans-fats are particularly harmful (these are from hydrogenated oils including hydrogenated margarines). It is probably true that omega-6 fatty acids (present in vegetable or soybean oils), while necessary in moderation, are over-abundant in western diets. Saturated fats (such as from red meat and dairy) have been associated with worse health outcomes.
Yet, as I review the literature, I see that this assumption about saturated fat may not be as clear as what most people assume. I intend to review this literature more thoroughly, and add to this post later. It may be that saturated fats from plant foods such as coconut are more benign. And it may be that health problems associated with eating a lot of red meat are due to factors aside from the saturated fat content.
*As I look into the coconut oil issue, I see there is a tremendous amount of hype and salesmanship going on--it seems to be touted as some kind of miracle food, also with a variety of scientific claims (e.g. about medium-chain triglyceride content) intended to strengthen the persuasion. When I look into what the research literature has to say, there really isn't a lot out there. What is out there at this point is not very consistent. It is true that there are groups of people, such as in Polynesia, who consume a lot of coconut oils, apparently without developing high rates of heart disease. In any case, I think it is fair to say that coconut or coconut oil in small quantities could be reasonably included in a healthy diet.
Clearly healthy sources of fat include fish, olive oil, nuts, avocados, and canola oil.
There are several types of cholesterol in the blood, the main subtypes being LDL and HDL. High LDL is a risk factor for cardiovascular disease (e.g. heart attacks and strokes). HDL is considered "the good cholesterol", and it is quite clear that higher HDL levels reduce the risk of developing cardiovascular disease. It is possible to increase HDL by exercising regularly, maintaining a healthy weight, stopping smoking, increasing dietary intake of monounsaturated fat (e.g. olive oil & canola oils), and increasing soluble fiber in the diet (e.g. oats, fruits, vegetables, legumes). 1-2 drinks per day (but no more) of alcohol may favourably impact HDL levels and overall health. It is important to note that the actual cholesterol present in certain foods, such as eggs, has an inconsistent relationship with serum cholesterol levels (perhaps a stronger relationship in some people than others), and an even less consistent effect on health variables--so cholesterol content of foods need not be a particularly important variable to assess.
(reference:http://www.ncbi.nlm.nih.gov/pubmed/18726564
In this 1998 study from the British Journal of Nutrition, subjects initially consumed a diet with 41% of calories coming from fat, then half of these subjects switched to a low-fat diet with only 25% of calories from fat. The group with the lower-fat diet developed higher levels of anger, hostility, and anxiety compared to the group continuing the higher-fat diet:
http://www.ncbi.nlm.nih.gov/pubmed/9505799
In this 2008 meta-analysis from Annals of Behavioural Medicine, an inverse association is found between serum cholesterol levels and depression. It is an interesting and surprising finding, given that we recognize lower cholesterol levels as beneficial for your heart:
http://www.ncbi.nlm.nih.gov/pubmed/18787911
In this 2008 study, a group with chronic depression was compared with a group with normal mood, and it was found that depression was associated with lower HDL levels (i.e. lower "good cholesterol"), even after controlling for several confounding factors. This type of study is unfortunately a bit weak. Here's a link to the abstract:
http://www.ncbi.nlm.nih.gov/pubmed/18583011
Here's a reference to a 2003 article from Encephale reviewing some of the evidence about low cholesterol being associated with depression and suicide. The authors also suggest that inadequate omega-3 fatty acids compared to omega-6 fatty acids in the diet may be a contributing factor to higher rates of depression.
http://www.ncbi.nlm.nih.gov/pubmed/12640327
This is a small but convincing 2008 study which showed significantly lower cholesterol levels in suicidal patients with schizoaffective disorder, compared to non-suicidal patients with schizoaffective disorder, and compared to healthy controls. HDL (the "good cholesterol") was higher in the non-suicidal patients and in the control group. The groups did not differ significantly with respect to BMI, so the association between cholesterol and symptoms would not have been due to weight.
http://www.ncbi.nlm.nih.gov/pubmed/17850945
Here's another 2007 study showing low cholesterol levels in an elderly group with cognitive impairment, and in an elderly group with depression, compared to a healthy elderly group.
http://www.ncbi.nlm.nih.gov/pubmed/17712096
Here's a 2007 study showing strong association between higher HDL cholesterol and better physical functioning among the oldest elderly (over 80 years old):
http://www.ncbi.nlm.nih.gov/pubmed/17913756
Here's a 2004 review describing the many findings about higher HDL being associated with better physical and mental functioning in the elderly, and in particular that people who live over 100 years have higher HDL levels:
http://www.ncbi.nlm.nih.gov/pubmed/15557706
In this strong, prospective 2009 study following 1,468 nurses with type II diabetes, higher dietary saturated and trans fat intake, and a lower ratio of polyunsaturated fat to saturated fat in the diet, was associated with worse cognitive decline (those in the highest third of saturated+trans fat intake effectively aged an extra 7 years with respect to cognitive decline, compared to those in the lowest third):
http://www.ncbi.nlm.nih.gov/pubmed/19336640
Here's a similar 2004 article from Neurology showing worse cognitive decline associated with higher saturated fat intake, lower monounsaturated fat intake, and a lower ratio of polyunsaturated to saturated fat intake:
http://www.ncbi.nlm.nih.gov/pubmed/15136684
In this strong, prospective, randomized 2007 study from JAMA, a diet with a low glycemic load (e.g. reducing simple sugars and increasing complex, slowly-digested carbs) and 35% of energy coming from fat, was compared with a low-fat diet (20% of energy from fat), with follow-up over 18 months. The higher-fat, low-glycemic load diet led to better improvement (increase) of HDL levels, and considerably better weight control:
http://www.ncbi.nlm.nih.gov/pubmed/17507345
The type of fat is important, though: trans-fats are particularly harmful (these are from hydrogenated oils including hydrogenated margarines). It is probably true that omega-6 fatty acids (present in vegetable or soybean oils), while necessary in moderation, are over-abundant in western diets. Saturated fats (such as from red meat and dairy) have been associated with worse health outcomes.
Yet, as I review the literature, I see that this assumption about saturated fat may not be as clear as what most people assume. I intend to review this literature more thoroughly, and add to this post later. It may be that saturated fats from plant foods such as coconut are more benign. And it may be that health problems associated with eating a lot of red meat are due to factors aside from the saturated fat content.
*As I look into the coconut oil issue, I see there is a tremendous amount of hype and salesmanship going on--it seems to be touted as some kind of miracle food, also with a variety of scientific claims (e.g. about medium-chain triglyceride content) intended to strengthen the persuasion. When I look into what the research literature has to say, there really isn't a lot out there. What is out there at this point is not very consistent. It is true that there are groups of people, such as in Polynesia, who consume a lot of coconut oils, apparently without developing high rates of heart disease. In any case, I think it is fair to say that coconut or coconut oil in small quantities could be reasonably included in a healthy diet.
Clearly healthy sources of fat include fish, olive oil, nuts, avocados, and canola oil.
There are several types of cholesterol in the blood, the main subtypes being LDL and HDL. High LDL is a risk factor for cardiovascular disease (e.g. heart attacks and strokes). HDL is considered "the good cholesterol", and it is quite clear that higher HDL levels reduce the risk of developing cardiovascular disease. It is possible to increase HDL by exercising regularly, maintaining a healthy weight, stopping smoking, increasing dietary intake of monounsaturated fat (e.g. olive oil & canola oils), and increasing soluble fiber in the diet (e.g. oats, fruits, vegetables, legumes). 1-2 drinks per day (but no more) of alcohol may favourably impact HDL levels and overall health. It is important to note that the actual cholesterol present in certain foods, such as eggs, has an inconsistent relationship with serum cholesterol levels (perhaps a stronger relationship in some people than others), and an even less consistent effect on health variables--so cholesterol content of foods need not be a particularly important variable to assess.
(reference:http://www.ncbi.nlm.nih.gov/pubmed/18726564
In this 1998 study from the British Journal of Nutrition, subjects initially consumed a diet with 41% of calories coming from fat, then half of these subjects switched to a low-fat diet with only 25% of calories from fat. The group with the lower-fat diet developed higher levels of anger, hostility, and anxiety compared to the group continuing the higher-fat diet:
http://www.ncbi.nlm.nih.gov/pubmed/9505799
In this 2008 meta-analysis from Annals of Behavioural Medicine, an inverse association is found between serum cholesterol levels and depression. It is an interesting and surprising finding, given that we recognize lower cholesterol levels as beneficial for your heart:
http://www.ncbi.nlm.nih.gov/pubmed/18787911
In this 2008 study, a group with chronic depression was compared with a group with normal mood, and it was found that depression was associated with lower HDL levels (i.e. lower "good cholesterol"), even after controlling for several confounding factors. This type of study is unfortunately a bit weak. Here's a link to the abstract:
http://www.ncbi.nlm.nih.gov/pubmed/18583011
Here's a reference to a 2003 article from Encephale reviewing some of the evidence about low cholesterol being associated with depression and suicide. The authors also suggest that inadequate omega-3 fatty acids compared to omega-6 fatty acids in the diet may be a contributing factor to higher rates of depression.
http://www.ncbi.nlm.nih.gov/pubmed/12640327
This is a small but convincing 2008 study which showed significantly lower cholesterol levels in suicidal patients with schizoaffective disorder, compared to non-suicidal patients with schizoaffective disorder, and compared to healthy controls. HDL (the "good cholesterol") was higher in the non-suicidal patients and in the control group. The groups did not differ significantly with respect to BMI, so the association between cholesterol and symptoms would not have been due to weight.
http://www.ncbi.nlm.nih.gov/pubmed/17850945
Here's another 2007 study showing low cholesterol levels in an elderly group with cognitive impairment, and in an elderly group with depression, compared to a healthy elderly group.
http://www.ncbi.nlm.nih.gov/pubmed/17712096
Here's a 2007 study showing strong association between higher HDL cholesterol and better physical functioning among the oldest elderly (over 80 years old):
http://www.ncbi.nlm.nih.gov/pubmed/17913756
Here's a 2004 review describing the many findings about higher HDL being associated with better physical and mental functioning in the elderly, and in particular that people who live over 100 years have higher HDL levels:
http://www.ncbi.nlm.nih.gov/pubmed/15557706
In this strong, prospective 2009 study following 1,468 nurses with type II diabetes, higher dietary saturated and trans fat intake, and a lower ratio of polyunsaturated fat to saturated fat in the diet, was associated with worse cognitive decline (those in the highest third of saturated+trans fat intake effectively aged an extra 7 years with respect to cognitive decline, compared to those in the lowest third):
http://www.ncbi.nlm.nih.gov/pubmed/19336640
Here's a similar 2004 article from Neurology showing worse cognitive decline associated with higher saturated fat intake, lower monounsaturated fat intake, and a lower ratio of polyunsaturated to saturated fat intake:
http://www.ncbi.nlm.nih.gov/pubmed/15136684
In this strong, prospective, randomized 2007 study from JAMA, a diet with a low glycemic load (e.g. reducing simple sugars and increasing complex, slowly-digested carbs) and 35% of energy coming from fat, was compared with a low-fat diet (20% of energy from fat), with follow-up over 18 months. The higher-fat, low-glycemic load diet led to better improvement (increase) of HDL levels, and considerably better weight control:
http://www.ncbi.nlm.nih.gov/pubmed/17507345
Tuesday, February 24, 2009
Caffeine & Coffee : Health Benefits
So, is coffee good for you? Or is it bad for you?
How about decaf?
It seems that there are mixed messages out there, about health effects from things such as coffee or caffeine.
What does the evidence tell us?
The evidence base is extremely compelling --
Here is a link to a study by Lopez-Garcia et al. from Annals of Internal Medicine in 2008, involving over 100 000 people, over 18 years of follow-up. Such massive studies with long follow-up time are incredibly informative:
http://www.ncbi.nlm.nih.gov/pubmed/18559841
In the study, it shows clearly that coffee drinkers have lower overall mortality rates, mainly due to a reduction in rates of cardiovascular disease. It showed a modest reduction in mortality rates associated with decaffeinated coffee as well. The authors conclude that the potential health benefits from coffee are due to components in the coffee other than caffeine.
The graph on the top is copied from the paper, and summarizes the results from the study. You can click on the graph to expand it. Actually, the data as presented on the graph suggests that people are healthier who have 2-3 cups of coffee per day, compared to those who have just 1.
Perhaps the less desirable effects from just a single cup per day are due to the more pronounced "jolt" of caffeine that would happen in a person who is not used to drinking as much coffee. Perhaps this effect would offset the health benefit, at low doses. At higher doses, the body may become more tolerant to caffeine's anxiogenic effects.
Unfortunately, this study did not look at mental health effects from drinking coffee, or from caffeine intake.
In another large epidemiological study of over 1400 people followed over 21 years, it was found that those who consumed coffee in mid-life had a substantially lower risk of developing dementia. This association was true after adjustment for demographic differences, lifestyle, and vascular disease.
http://www.ncbi.nlm.nih.gov/pubmed/19158424
This case-control study from Archives of Neurology in 2007 showed an inverse association between coffee intake and development of Parkinson disease (i.e. this relationship suggests that coffee could protect the brain from disease such as Parkinson's). However, smaller case-control studies such as this one are much weaker than the large prospective studies cited above:
http://www.ncbi.nlm.nih.gov/pubmed/17420321
The following 2008 article from Sleep Medicine Reviews presents a more cautionary account of caffeine's effects, particularly with respect to causing a dependence phenomenon, and to disrupting sleep quality. However, a lot of the data cited in this article is absurd, such as showing that a dose of caffeine immediately before sleep causes sleep disruption! Bedtime doses of coffee are not a realistic reflection of most people's caffeine intake!
http://www.ncbi.nlm.nih.gov/pubmed/17950009
Here's an interesting reference to an article showing that the tendency for caffeine to cause sleep disturbance is a heritable trait. That is, some people might be vulnerable to caffeine-induced insomnia, whereas others could sleep well regardless of their caffeine intake:
http://www.ncbi.nlm.nih.gov/pubmed/17969472
Here's a case report of a person with schizoaffective disorder improving upon discontinuing heavy caffeine intake:
http://www.ncbi.nlm.nih.gov/pubmed/18455857
In summary, it appears that coffee drinking is not harmful. In most cases, it may in fact be good for you. However, pregnant women should minimize their use of coffee. For some people, caffeine may cause or exacerbate anxiety or insomnia, especially at higher doses.
Monday, February 23, 2009
Ferritin & Iron
Ferritin levels in the blood correlate well with the amount of iron available in the body's "reservoir". If ferritin levels are low, the body has very low reserves of iron. (the converse may NOT be true -- if ferritin levels are high, the body may still have low iron reserves, because there are a variety of conditions, such as inflammatory states, that can cause ferritin levels to rise)
Anemia is a condition in which the body does not have enough iron-containing red blood cells, therefore the body cannot deliver oxygen to the tissues (including the muscles, heart, and brain) as efficiently. One of the most common symptoms of anemia, not surprisingly, is fatigue.
Sometimes, iron reserves can be low, without actually causing anemia. It is like a low water reservoir: water may still be flowing into people's homes despite the water levels being low.
Here is a 2003 study from the major journal, BMJ, which shows that iron supplementation improves fatigue in non-anemic women with low ferritin:
http://www.ncbi.nlm.nih.gov/pubmed/12763985
This study, from the major medical journal Lancet in 1996, shows that iron supplementation given to non-anemic girls with low ferritin improved their verbal learning and memory:
http://www.ncbi.nlm.nih.gov/pubmed/8855856
Low ferritin levels are associated with a disease called "restless legs syndrome" (RLS), which causes discomfort and insomnia at night, and which can often give rise to a substantial reduction in quality of life. I suspect there are many milder cases of RLS which could be contributing to insomnia, and therefore contributing to resulting anxiety and mood problems. Here are some studies showing the association, and demonstrating that iron supplementation can improve RLS:
http://www.ncbi.nlm.nih.gov/pubmed/15854860
http://www.ncbi.nlm.nih.gov/pubmed/8085504
http://www.ncbi.nlm.nih.gov/pubmed/19200780
In this recent study from the Journal of Pediatric Neurology, children with ADHD and low ferritin levels showed improvement in their ADHD symptoms after receiving iron supplements:
http://www.ncbi.nlm.nih.gov/pubmed/18054688
In conclusion, I believe it is very important to evaluate ferritin levels, particularly in women, since the levels are frequently low; low ferritin is associated with fatigue, restless legs, ADHD, and reduced cognitive function. It could be a contributing factor to mood disorders and other psychiatric problems.
Usually, low ferritin levels are easily remedied by iron supplementation. Most daily multivitamins contain iron, but the amount of iron in these is usually enough only to maintain your iron stores, not to build them up. Similarly, increasing iron-rich foods in the diet will help to maintain or build iron stores, but this could take a very long time. In order to build up your iron stores more quickly, higher doses of iron salts, such as ferrous sulphate, need to be taken daily for several months.
I recommend aiming for a serum level of at least 50 micrograms / litre (50 ug/L). Many labs give a normal range starting at 20 ug/L, and therefore you may not hear from your physician if the level comes back at 25. It is important to know that the average for women is at least 50, and the average for men is about 100. Exceptions include children, whose ferritin levels are a little lower, and women in advanced stages of pregnancy, who have average ferritin levels of only about 20.
If you do have low ferritin, then further investigation could be warranted, to assess for other causes of iron deficiency (e.g. chronic blood loss from the digestive tract, from heavy menstrual flow, or from the kidneys). So your decisions on this matter should be discussed and followed-up with a primary care physician.
Anemia is a condition in which the body does not have enough iron-containing red blood cells, therefore the body cannot deliver oxygen to the tissues (including the muscles, heart, and brain) as efficiently. One of the most common symptoms of anemia, not surprisingly, is fatigue.
Sometimes, iron reserves can be low, without actually causing anemia. It is like a low water reservoir: water may still be flowing into people's homes despite the water levels being low.
Here is a 2003 study from the major journal, BMJ, which shows that iron supplementation improves fatigue in non-anemic women with low ferritin:
http://www.ncbi.nlm.nih.gov/pubmed/12763985
This study, from the major medical journal Lancet in 1996, shows that iron supplementation given to non-anemic girls with low ferritin improved their verbal learning and memory:
http://www.ncbi.nlm.nih.gov/pubmed/8855856
Low ferritin levels are associated with a disease called "restless legs syndrome" (RLS), which causes discomfort and insomnia at night, and which can often give rise to a substantial reduction in quality of life. I suspect there are many milder cases of RLS which could be contributing to insomnia, and therefore contributing to resulting anxiety and mood problems. Here are some studies showing the association, and demonstrating that iron supplementation can improve RLS:
http://www.ncbi.nlm.nih.gov/pubmed/15854860
http://www.ncbi.nlm.nih.gov/pubmed/8085504
http://www.ncbi.nlm.nih.gov/pubmed/19200780
In this recent study from the Journal of Pediatric Neurology, children with ADHD and low ferritin levels showed improvement in their ADHD symptoms after receiving iron supplements:
http://www.ncbi.nlm.nih.gov/pubmed/18054688
In conclusion, I believe it is very important to evaluate ferritin levels, particularly in women, since the levels are frequently low; low ferritin is associated with fatigue, restless legs, ADHD, and reduced cognitive function. It could be a contributing factor to mood disorders and other psychiatric problems.
Usually, low ferritin levels are easily remedied by iron supplementation. Most daily multivitamins contain iron, but the amount of iron in these is usually enough only to maintain your iron stores, not to build them up. Similarly, increasing iron-rich foods in the diet will help to maintain or build iron stores, but this could take a very long time. In order to build up your iron stores more quickly, higher doses of iron salts, such as ferrous sulphate, need to be taken daily for several months.
I recommend aiming for a serum level of at least 50 micrograms / litre (50 ug/L). Many labs give a normal range starting at 20 ug/L, and therefore you may not hear from your physician if the level comes back at 25. It is important to know that the average for women is at least 50, and the average for men is about 100. Exceptions include children, whose ferritin levels are a little lower, and women in advanced stages of pregnancy, who have average ferritin levels of only about 20.
If you do have low ferritin, then further investigation could be warranted, to assess for other causes of iron deficiency (e.g. chronic blood loss from the digestive tract, from heavy menstrual flow, or from the kidneys). So your decisions on this matter should be discussed and followed-up with a primary care physician.
Tuesday, February 10, 2009
Omega-3 Supplementation
Omega-3 fatty acids are present in a variety of foods.
The fatty acids EPA and DHA are present mainly in fish such as salmon, herring, mackerel, anchovies, and sardines. These fatty acids, especially DHA, are probably important for brain function, and are also found in the retina of the eye.
Another omega-3 fatty acid, ALA, is present from plant sources such as canola oil, flax, and walnuts. ALA may be converted in the body to DHA.
There is some evidence that there are health benefits from diets higher in omega-3 fatty acids, or diets supplemented with extra omega-3.
Of interest for psychiatry, omega-3 supplementation may be a safe adjunct in the treatment of depression. Fish oil is probably the simplest source of extra EPA and DHA.
The only problem with increasing fish consumption is the exposure to environmental contaminants such as mercury and PCBs. Fish oil capsules may actually have less of these contaminants than pure fish, especially if the oil has been refined to remove contaminants. In any case, I think the benefit-risk ratio is very favourable, and that 1-3 capsules per day of fish oil is quite safe. And I feel confident to recommend increased fish intake in the diet. For vegetarians, increased intake of walnuts, canola, and flax could be recommended.
http://www.ncbi.nlm.nih.gov/pubmed/18183532
(a review of the studies over the past decade looking at omega-3 supplements in mood disorders)
http://www.ncbi.nlm.nih.gov/pubmed/16741195
(a nice review from The American Journal of Psychiatry in 2006, summarizing epidemiological data associating low fish consumption with higher rates of mood disorder, and summarizing some of the treatment studies showing antidepressant effects of omega-3 supplements in depression, bipolar disorder, and borderline personality)
http://www.ncbi.nlm.nih.gov/pubmed/19156158
(this is a recent study showing beneficial effects of omega-3 supplements in children with bipolar symptoms;but it was not a randomized or controlled study)
http://www.ncbi.nlm.nih.gov/pubmed/19200125
(this is a recent local study analyzing fish oil supplements for environmental pollutant levels, such as PCBs. Based on this study, one should avoid supplements of products such as seal or shark oils, which have much higher contaminant levels.)
http://www.ncbi.nlm.nih.gov/pubmed/19139352
(one of the articles summarizing evidence that omega-3 intake reduces the incidence or progression of macular degeneration, which is a common cause of visual loss in those over 65 years of age).
http://www.ncbi.nlm.nih.gov/pubmed/19064523
(a huge study, published in 2006, involving data from over
40 000 people over 18 years of follow-up--it shows a slight reduction in cardiac disease associated with higher fish consumption, but no change in overall "major chronic disease risk". But, incredibly, and unfortunately, they did not include mood or other psychiatric disorders in their assessment of "chronic disease" outcomes. Yet, studies of this type exemplify that The American Journal of Clinical Nutrition is an excellent journal, a valuable and practical source of evidence-based health information which could guide nutritional choices).
The fatty acids EPA and DHA are present mainly in fish such as salmon, herring, mackerel, anchovies, and sardines. These fatty acids, especially DHA, are probably important for brain function, and are also found in the retina of the eye.
Another omega-3 fatty acid, ALA, is present from plant sources such as canola oil, flax, and walnuts. ALA may be converted in the body to DHA.
There is some evidence that there are health benefits from diets higher in omega-3 fatty acids, or diets supplemented with extra omega-3.
Of interest for psychiatry, omega-3 supplementation may be a safe adjunct in the treatment of depression. Fish oil is probably the simplest source of extra EPA and DHA.
The only problem with increasing fish consumption is the exposure to environmental contaminants such as mercury and PCBs. Fish oil capsules may actually have less of these contaminants than pure fish, especially if the oil has been refined to remove contaminants. In any case, I think the benefit-risk ratio is very favourable, and that 1-3 capsules per day of fish oil is quite safe. And I feel confident to recommend increased fish intake in the diet. For vegetarians, increased intake of walnuts, canola, and flax could be recommended.
http://www.ncbi.nlm.nih.gov/pubmed/18183532
(a review of the studies over the past decade looking at omega-3 supplements in mood disorders)
http://www.ncbi.nlm.nih.gov/pubmed/16741195
(a nice review from The American Journal of Psychiatry in 2006, summarizing epidemiological data associating low fish consumption with higher rates of mood disorder, and summarizing some of the treatment studies showing antidepressant effects of omega-3 supplements in depression, bipolar disorder, and borderline personality)
http://www.ncbi.nlm.nih.gov/pubmed/19156158
(this is a recent study showing beneficial effects of omega-3 supplements in children with bipolar symptoms;but it was not a randomized or controlled study)
http://www.ncbi.nlm.nih.gov/pubmed/19200125
(this is a recent local study analyzing fish oil supplements for environmental pollutant levels, such as PCBs. Based on this study, one should avoid supplements of products such as seal or shark oils, which have much higher contaminant levels.)
http://www.ncbi.nlm.nih.gov/pubmed/19139352
(one of the articles summarizing evidence that omega-3 intake reduces the incidence or progression of macular degeneration, which is a common cause of visual loss in those over 65 years of age).
http://www.ncbi.nlm.nih.gov/pubmed/19064523
(a huge study, published in 2006, involving data from over
40 000 people over 18 years of follow-up--it shows a slight reduction in cardiac disease associated with higher fish consumption, but no change in overall "major chronic disease risk". But, incredibly, and unfortunately, they did not include mood or other psychiatric disorders in their assessment of "chronic disease" outcomes. Yet, studies of this type exemplify that The American Journal of Clinical Nutrition is an excellent journal, a valuable and practical source of evidence-based health information which could guide nutritional choices).
Wednesday, February 4, 2009
Vitamin D & other vitamins
I'm re-posting this as a separate entry, because I think it's important.
I recommend multivitamin supplements as standard advice, because I think there is negligible evidence of risk (other than the effect on your wallet), and potential benefit.
The role of vitamin supplements ought not to be overvalued -- I think they are unlikely to cause a pronounced change in any symptom. But a vitamin deficiency could possibly prevent other treatments for depression from working optimally. Many people with psychiatric symptoms have less than optimal nutrition, for various reasons; therefore I feel that vitamin and mineral deficiencies are more likely.
There is some evidence of vitamin supplements being used to augment antidepressant medications, but the level of evidence is quite weak.
Vitamin D in particular is probably important to supplement, particularly for those of us who experience dark, cold northerly winters (vitamin D is normally produced in the body when our skin is exposed to the ultraviolet rays from direct sunlight). Furthermore, most of us wisely use sunscreen when it is sunny and warm, so most of us are getting less vitamin D from the sun. There is some evidence that the RDA for vitamin D (200-400 IU per day) is too low, particularly when we consider that brief whole-body skin exposure to sunlight generates an equivalent of perhaps 10 000 IU.
Here is a reference to a very interesting and promising recent study suggesting beneficial mood effects from higher-dose vitamin D supplementation (people received the equivalent of about 3000-6000 IU per day, for a whole year); the study is from a major, highly respected internal medicine journal:
http://www.ncbi.nlm.nih.gov/pubmed/18793245
Here is an excellent reference examining the issue of vitamin D safety, dosage, and toxicity:
Vieth, Reinhold. "Vitamin D supplementation, 25-hydroxyvitamin D concentrations, and safety", American Journal of Clinical Nutrition 1999;69:842–56
A recent study by Bischoff-Ferrari et al. (2009) showed that elderly hip fracture patients given 2000 IU per day of vitamin D for 12 months, had a 60% reduction in fall-related injuries and a 90% reduction in infections leading to hospitalization, compared to a group given only 800 IU per day of vitamin D.
Here's a reference to a 2008 study from a clinical biochemistry journal showing toxicity from prolonged very high-dose vitamin D, of over 40 000 IU/day over several years. It concludes that the lowest dose at which hypercalcemia can occur is about 3800 IU per day:
http://www.ncbi.nlm.nih.gov/pubmed/18275686
Based on the evidence I recommend supplementing with an extra 2000 IU of vitamin D daily (possibly up to 3000 IU), in addition to the 400 IU that is present in most vitamin supplements, unless you have a medical condition associated with abnormal calcium metabolism or abnormal sensitivity to vitamin D (e.g. sarcoidosis).
If you are taking high-dose vitamin D you should have serum calcium levels checked periodically, and possibly a serum vitamin D level.
I do not recommend "mega doses" of any other vitamin, since I do not see a good evidence base for this being helpful, and higher doses of many such nutrients can be toxic or dangerous. A few recent studies have shown that people taking certain vitamin supplements, such as vitamin A or E, actually do more poorly than the control group.
I recommend multivitamin supplements as standard advice, because I think there is negligible evidence of risk (other than the effect on your wallet), and potential benefit.
The role of vitamin supplements ought not to be overvalued -- I think they are unlikely to cause a pronounced change in any symptom. But a vitamin deficiency could possibly prevent other treatments for depression from working optimally. Many people with psychiatric symptoms have less than optimal nutrition, for various reasons; therefore I feel that vitamin and mineral deficiencies are more likely.
There is some evidence of vitamin supplements being used to augment antidepressant medications, but the level of evidence is quite weak.
Vitamin D in particular is probably important to supplement, particularly for those of us who experience dark, cold northerly winters (vitamin D is normally produced in the body when our skin is exposed to the ultraviolet rays from direct sunlight). Furthermore, most of us wisely use sunscreen when it is sunny and warm, so most of us are getting less vitamin D from the sun. There is some evidence that the RDA for vitamin D (200-400 IU per day) is too low, particularly when we consider that brief whole-body skin exposure to sunlight generates an equivalent of perhaps 10 000 IU.
Here is a reference to a very interesting and promising recent study suggesting beneficial mood effects from higher-dose vitamin D supplementation (people received the equivalent of about 3000-6000 IU per day, for a whole year); the study is from a major, highly respected internal medicine journal:
http://www.ncbi.nlm.nih.gov/pubmed/18793245
Here is an excellent reference examining the issue of vitamin D safety, dosage, and toxicity:
Vieth, Reinhold. "Vitamin D supplementation, 25-hydroxyvitamin D concentrations, and safety", American Journal of Clinical Nutrition 1999;69:842–56
A recent study by Bischoff-Ferrari et al. (2009) showed that elderly hip fracture patients given 2000 IU per day of vitamin D for 12 months, had a 60% reduction in fall-related injuries and a 90% reduction in infections leading to hospitalization, compared to a group given only 800 IU per day of vitamin D.
Here's a reference to a 2008 study from a clinical biochemistry journal showing toxicity from prolonged very high-dose vitamin D, of over 40 000 IU/day over several years. It concludes that the lowest dose at which hypercalcemia can occur is about 3800 IU per day:
http://www.ncbi.nlm.nih.gov/pubmed/18275686
Based on the evidence I recommend supplementing with an extra 2000 IU of vitamin D daily (possibly up to 3000 IU), in addition to the 400 IU that is present in most vitamin supplements, unless you have a medical condition associated with abnormal calcium metabolism or abnormal sensitivity to vitamin D (e.g. sarcoidosis).
If you are taking high-dose vitamin D you should have serum calcium levels checked periodically, and possibly a serum vitamin D level.
I do not recommend "mega doses" of any other vitamin, since I do not see a good evidence base for this being helpful, and higher doses of many such nutrients can be toxic or dangerous. A few recent studies have shown that people taking certain vitamin supplements, such as vitamin A or E, actually do more poorly than the control group.
Monday, October 27, 2008
Sugar
Many people believe that sugar (sucrose) intake causes behavioural problems. The two most common specific beliefs are that eating sugar causes worsened hyperactivity; or that eating sugar causes a rush of energy, followed by a plunge into fatigue as the sugar level "crashes".
In fact there have been a lot of very good studies looking at this, and the evidence is quite clear that sugar does not cause hyperactivity. There is an association between high sugar intake and antisocial behaviour, but the relationship is probably not causal. It is much more plausible that those with more antisocial behaviour in the first place happen to choose to consume more sugar.
In some of the prospective, randomized studies, in fact, individuals consuming sugar (instead of a placebo) did better, particularly in terms of learning tasks.
The evidence is also very clear that so-called "reactive hypoglycemia" is very rare, even in people who insist that they have it. However, there may be some individuals who become more irritable as their blood glucose level drops, even if the drop is not down to clinically hypoglycemic levels.
There is evidence that some individuals may respond adversely, in terms of their behaviour, to certain foods, but actually sugar is not a common such food, according to well-controlled studies.
I do affirm that moderating sugar intake, and also eating meals with a lower glycemic index, is part of overall good long-term health.
But most of the claims about sugar influencing behaviour adversely are part of a myth, not supported by clear evidence.
For an excellent review of the evidence on this matter, see this article by David Benton (May 2008):
http://www.informaworld.com/smpp/content~db=all?content=10.1080/10408390701407316
In fact there have been a lot of very good studies looking at this, and the evidence is quite clear that sugar does not cause hyperactivity. There is an association between high sugar intake and antisocial behaviour, but the relationship is probably not causal. It is much more plausible that those with more antisocial behaviour in the first place happen to choose to consume more sugar.
In some of the prospective, randomized studies, in fact, individuals consuming sugar (instead of a placebo) did better, particularly in terms of learning tasks.
The evidence is also very clear that so-called "reactive hypoglycemia" is very rare, even in people who insist that they have it. However, there may be some individuals who become more irritable as their blood glucose level drops, even if the drop is not down to clinically hypoglycemic levels.
There is evidence that some individuals may respond adversely, in terms of their behaviour, to certain foods, but actually sugar is not a common such food, according to well-controlled studies.
I do affirm that moderating sugar intake, and also eating meals with a lower glycemic index, is part of overall good long-term health.
But most of the claims about sugar influencing behaviour adversely are part of a myth, not supported by clear evidence.
For an excellent review of the evidence on this matter, see this article by David Benton (May 2008):
http://www.informaworld.com/smpp/content~db=all?content=10.1080/10408390701407316
Friday, October 17, 2008
Vitamins & other nutritional supplements
There are many people who believe that nutritional supplements can help with a variety of health problems. There is a field called "orthomolecular psychiatry", in which the practioners believe that vitamin supplements and other nutritional adjuncts can treat mental illnesses. I consider many of these beliefs to be spurious, and to be lacking a significant evidence base. I think many of those who benefit from these treatments are experiencing a combination of a placebo effect, and are perhaps benefiting from the psychotherapeutic care involved as well. Perhaps some of these individuals are also benefiting from not having the side-effects of other conventional therapies that were not working for them.
Here is a look at the evidence regarding vitamin supplementation; I restrict any references to journals that I consider to have a high professional standard:
1) Folic acid. There are a few studies which suggest that folic acid supplements may help augment the effectiveness of antidepressants. Here are a few references:
http://www.ncbi.nlm.nih.gov/pubmed/10967371
(in this study, adding 0.5 mg of folic acid daily to the antidepressant fluoxetine, improved depression severity, in women only)
http://www.ncbi.nlm.nih.gov/pubmed/15323594
and
http://www.ncbi.nlm.nih.gov/pubmed/15323595
(In these studies, low folic acid levels were strongly associated with resistance to fluoxetine treatment and more frequent depressive relapse. However, I am curious to know if this is merely an association--that is, whether the low-folic acid level group had other factors such as generalized poor nutrition or self-care, etc. that caused them to be more treatment-resistant.)
2) Thiamine (vitamin B1)
Thiamine can treat and prevent an extremely severe neurological syndrome called Wernicke-Korsakov encephalopathy; this syndrome occurs in nutritionally-deficient alcoholics, and causes devastating, permanent, sometimes total inability to form short-term memories. But there is not a lot of evidence about using thiamine to help other psychiatric disorders. Mind you, it hasn't been studied much. There are a few studies in the elderly, which suggest that thiamine supplementation helps with energy and well-being:
http://www.ncbi.nlm.nih.gov/pubmed/1986037
3) Other B vitamins:
Here's a study showing a relationship between folic acid levels--but not any other B vitamins or omega-3 fatty acid levels--and depressive symptoms in a group of Japanese adults.
http://www.ncbi.nlm.nih.gov/pubmed/18061404
Vitamin b-6: High doses may cause damage to sensory nerves, and I would not recommend taking more than 10 mg daily. Most daily multivitamins have about 3 mg. The toxicity is quite clear for doses over 100 mg/d.
http://www.ncbi.nlm.nih.gov/pubmed/16320662
http://www.ncbi.nlm.nih.gov/pubmed/14584010
Here is a reference to a new study including over 5000 women, over 7 years of follow-up, from Archives of Internal Medicine. It showed significantly reduced rates of macular degeneration in a large cohort of people taking high-dose b-vitamins (2.5 mg/d of folic acid; 50 mg/d of b-6; 1000 mcg/d of b12):
http://archinte.ama-assn.org/cgi/content/full/169/4/335
4) Vitamin D
There is accumulating evidence that higher doses of vitamin D are beneficial for a variety of health variables. Also, it is becoming apparent that many people are vitamin-D deficient, especially those who live in northern climates. Most supplements contain 400 IU, but probably a dose of at least 1000 IU daily could be recommended. Doses less than 10 000 IU have not been associated with toxicity, according to my review of the evidence, but we could conservatively say that doses up to 4000 IU daily are very likely to be safe, unless there is some medical disorder present (e.g. sarcoidosis) that causes a disturbance in calcium metabolism. Here is a very interesting and promising recent study suggesting beneficial mood effects from higher-dose vitamin D supplementation; the study is from a major, highly respected internal medicine journal:
http://www.ncbi.nlm.nih.gov/pubmed/18793245
It should be emphasized that more is not always better! Many vitamins cause toxicity if they are taken in excess. Also, some of the studies are showing that groups who took certain vitamin supplements (such as vitamin E and beta-carotene) actually fared more poorly, rather than better.
http://www.ncbi.nlm.nih.gov/pubmed/12876090
http://www.ncbi.nlm.nih.gov/pubmed/16645413
5) Omega-3 fatty acids
There is some evidence that omega-3 supplementation (containing the fatty acids EPA & DHA) can help reduce depressive symptoms, particularly in those with bipolar disorder. Omega-3 fatty acids can be found most abundantly in fish such as salmon. Plant sources include canola oil, flax, and walnuts (however, the plant sources only have one of the 3 types of omega-3 fatty acids). Here's a link to recent Cochrane Review abstract:
http://www.ncbi.nlm.nih.gov/pubmed/18425912
Here are some links to other reviews:
http://www.ncbi.nlm.nih.gov/pubmed/17685742med_RVDocSum
http://www.ncbi.nlm.nih.gov/pubmed/18370571
However the evidence appears to be fairly weak at this point, there may be some publication bias (i.e. studies showing no effect may not have been published) so more research really needs to be done. In the meantime, though, omega-3 supplementation (usually in the form of fish oil capsules) appears to be harmless, and potentially beneficial. The dose corresponding to what many of the studies used is about 3-6 grams of salmon oil daily (usually 3-6 capsules, each of which containing 1 gram).
Omega-3 supplementation may be beneficial in other ways--it may help protect against macular degeneration (vision deterioration during old age). Also there is some data showing that higher omega-3 intakes, or fish consumption, may slow the rate of cognitive decline in old age. Here's the best such study I could find showing this:
http://www.ncbi.nlm.nih.gov/pubmed/16216930
I suspect that some of the benefits from increasing omega-3 intake could be augmented by consuming a diet in which other unhealthy lipids are minimized--this would involve reducing omega-6 intake, eliminating trans fatty acids, and moderating the intake of saturated fats. I invite the interested reader to research this subject further.
Here is a look at the evidence regarding vitamin supplementation; I restrict any references to journals that I consider to have a high professional standard:
1) Folic acid. There are a few studies which suggest that folic acid supplements may help augment the effectiveness of antidepressants. Here are a few references:
http://www.ncbi.nlm.nih.gov/pubmed/10967371
(in this study, adding 0.5 mg of folic acid daily to the antidepressant fluoxetine, improved depression severity, in women only)
http://www.ncbi.nlm.nih.gov/pubmed/15323594
and
http://www.ncbi.nlm.nih.gov/pubmed/15323595
(In these studies, low folic acid levels were strongly associated with resistance to fluoxetine treatment and more frequent depressive relapse. However, I am curious to know if this is merely an association--that is, whether the low-folic acid level group had other factors such as generalized poor nutrition or self-care, etc. that caused them to be more treatment-resistant.)
2) Thiamine (vitamin B1)
Thiamine can treat and prevent an extremely severe neurological syndrome called Wernicke-Korsakov encephalopathy; this syndrome occurs in nutritionally-deficient alcoholics, and causes devastating, permanent, sometimes total inability to form short-term memories. But there is not a lot of evidence about using thiamine to help other psychiatric disorders. Mind you, it hasn't been studied much. There are a few studies in the elderly, which suggest that thiamine supplementation helps with energy and well-being:
http://www.ncbi.nlm.nih.gov/pubmed/1986037
3) Other B vitamins:
Here's a study showing a relationship between folic acid levels--but not any other B vitamins or omega-3 fatty acid levels--and depressive symptoms in a group of Japanese adults.
http://www.ncbi.nlm.nih.gov/pubmed/18061404
Vitamin b-6: High doses may cause damage to sensory nerves, and I would not recommend taking more than 10 mg daily. Most daily multivitamins have about 3 mg. The toxicity is quite clear for doses over 100 mg/d.
http://www.ncbi.nlm.nih.gov/pubmed/16320662
http://www.ncbi.nlm.nih.gov/pubmed/14584010
Here is a reference to a new study including over 5000 women, over 7 years of follow-up, from Archives of Internal Medicine. It showed significantly reduced rates of macular degeneration in a large cohort of people taking high-dose b-vitamins (2.5 mg/d of folic acid; 50 mg/d of b-6; 1000 mcg/d of b12):
http://archinte.ama-assn.org/cgi/content/full/169/4/335
4) Vitamin D
There is accumulating evidence that higher doses of vitamin D are beneficial for a variety of health variables. Also, it is becoming apparent that many people are vitamin-D deficient, especially those who live in northern climates. Most supplements contain 400 IU, but probably a dose of at least 1000 IU daily could be recommended. Doses less than 10 000 IU have not been associated with toxicity, according to my review of the evidence, but we could conservatively say that doses up to 4000 IU daily are very likely to be safe, unless there is some medical disorder present (e.g. sarcoidosis) that causes a disturbance in calcium metabolism. Here is a very interesting and promising recent study suggesting beneficial mood effects from higher-dose vitamin D supplementation; the study is from a major, highly respected internal medicine journal:
http://www.ncbi.nlm.nih.gov/pubmed/18793245
It should be emphasized that more is not always better! Many vitamins cause toxicity if they are taken in excess. Also, some of the studies are showing that groups who took certain vitamin supplements (such as vitamin E and beta-carotene) actually fared more poorly, rather than better.
http://www.ncbi.nlm.nih.gov/pubmed/12876090
http://www.ncbi.nlm.nih.gov/pubmed/16645413
5) Omega-3 fatty acids
There is some evidence that omega-3 supplementation (containing the fatty acids EPA & DHA) can help reduce depressive symptoms, particularly in those with bipolar disorder. Omega-3 fatty acids can be found most abundantly in fish such as salmon. Plant sources include canola oil, flax, and walnuts (however, the plant sources only have one of the 3 types of omega-3 fatty acids). Here's a link to recent Cochrane Review abstract:
http://www.ncbi.nlm.nih.gov/pubmed/18425912
Here are some links to other reviews:
http://www.ncbi.nlm.nih.gov/pubmed/17685742med_RVDocSum
http://www.ncbi.nlm.nih.gov/pubmed/18370571
However the evidence appears to be fairly weak at this point, there may be some publication bias (i.e. studies showing no effect may not have been published) so more research really needs to be done. In the meantime, though, omega-3 supplementation (usually in the form of fish oil capsules) appears to be harmless, and potentially beneficial. The dose corresponding to what many of the studies used is about 3-6 grams of salmon oil daily (usually 3-6 capsules, each of which containing 1 gram).
Omega-3 supplementation may be beneficial in other ways--it may help protect against macular degeneration (vision deterioration during old age). Also there is some data showing that higher omega-3 intakes, or fish consumption, may slow the rate of cognitive decline in old age. Here's the best such study I could find showing this:
http://www.ncbi.nlm.nih.gov/pubmed/16216930
I suspect that some of the benefits from increasing omega-3 intake could be augmented by consuming a diet in which other unhealthy lipids are minimized--this would involve reducing omega-6 intake, eliminating trans fatty acids, and moderating the intake of saturated fats. I invite the interested reader to research this subject further.
Wednesday, July 30, 2008
Healthy Eating
-lots of fresh vegetables & fruits (except for root vegetables), in amount and variety
-lots of high-fiber foods
-less meat, if any
-fish is healthy, especially fatty red fish such as salmon (an omega-3 source)
-but this has to be moderated due to the unfortunate risk of heavy metal contamination from eating a lot of fish, and due to the environmental problem of worldwide overfishing
-tea is good, in moderation (green & black), unless the caffeine is interfering with sleep
-dark chocolate is good for you; but it has to be in moderation, since it contains a lot of saturated fat
-carbohydrates (carbs) are probably important and necessary for mental health; low-carb ketotic diets are probably hard on the brain. But it is important to choose complex carbs that are released more gradually into your body. Sprouted whole grain breads are better. White bread or rice is almost like pure sugar, in terms of its rate of digestion into simple carbohydrates. Sugar itself should be cut down substantially (it has addictive properties; once you have gradually weaned sugar from cooking and baking, perhaps to 1/3 or 1/4 of what most recipes recommend, you will enjoy the intrinsic flavour of the baking more, and find the higher-sugar recipes unpleasantly sweet).
-components of the "Mediterranean" diet in which there is abundant use of olive oil, is probably healthy
-eliminate trans-fatty-acids from the diet (e.g. hydrogenated oils, often present in many packaged foods to prolong shelf life -- remember this may prolong the oil's "shelf life" on the inside of your arteries as well).
-there is some evidence that there is an excess of omega-6 fatty acids in the typical North American diet; this can be addressed by reducing use of omega-6 rich oils such as sunflower and corn oils, and instead using oils such as canola. Walnuts and flax are other natural sources of healthier omega-3 oils.
-1 to 2 glasses of wine (125-250 mL) per day may improve health compared to abstainers, and compared to those who drink more. But some individuals may have health problems as a result of drinking even small amounts of alcohol. In this case it is best to abstain.
-drinking water is great, but you really don't have to drink huge amounts. Keep yourself well-hydrated, but you only need to drink if you're thirsty.
-I do encourage people to leave all soft drinks behind -- the sugary ones are obviously bad for you. The ones with artificial sweeteners are probably not great for you either, and are also training you to expect sweetness while you hydrate yourself--this conditioning may exacerbate an unhealthy dependence upon simple carbohydrates and sweets, and cause you to be perceive the simple joy of drinking pure water to be unpleasantly mundane. Also do you really want to financially support the big soft-drink companies, with their expanding presence in children's schools, developing countries (many of whose people are dying from starvation), etc.?
-minimize the use of salt
-high-temperature cooking such as barbecuing adds flavour to food, but may result in higher levels of unhealthy chemicals, so it is probably best to reduce the intake of charred food.
-if you are a vegetarian or have other dietary restrictions, make sure you get an adequate intake of vitamins and minerals. A simple daily vitamin supplement should usually be sufficient. I do not see compelling evidence that "megadose" vitamins are beneficial.
-but there is some evidence that the RDA for vitamin D ought to be higher, perhaps up to 1000 IU per day or more.
-extra calcium supplementation may also be needed for many people on a long-term basis, to maintain bone health
While much of this advice is part of basic general health, I think that basic general health is also beneficial to mental health. And there may possibly be specific direct benefits to mental health from a very healthy diet.
I do qualify the above remarks, by saying that extremely clear, direct evidence linking healthy nutritional habits to improved mental health, is lacking. Much of the evidence is indirect or anecdotal. Many exaggerated claims are made in the advertising found in health-food stores. There are a few small studies looking at specific supplements, such as omega-3 supplements, which show some modest evidence that this can improve mood.
Some useful links:
1) the USDA nutrient database (detailed nutritional data about different foods):
http://www.nal.usda.gov/fnic/foodcomp/search/
2) the Cornell University food psychology page:
http://www.foodpsychology.cornell.edu/
The American Journal of Clinical Nutrition is a good academic journal to browse through, to get a good sense of what is going on in food & nutrition research. You can head to an academic library, and leaf through the past year's issues.
Addendum:
After reading the excellent comment on this entry, I feel compelled to add a few things to what I now recognize has been a very dry and pedantic set of comments:
I forgot to mention that I think food is one of the great joys and pleasures of life!
As with other joys, it is wonderful and healthy to develop and nurture a rich culinary experience.
Not only are food, cooking, and eating sources of sensual pleasure, they are also part of a rich and healthy culture (and a way to introduce oneself to new cultures), a part of a social and community life, and a part of an active intellectual life. It is a delight of human nature that we can start with something basic (e.g. an onion, or a grape), and keep refining it, transforming it, and using it in new ways, until we derive more and more art and pleasure from it. There is something very basic about the meaning of life itself in this kind of dynamic.
So I wholeheartedly endorse the idea of embracing and developing a rich culinary culture as part of healthy living. I do still maintain, however, that every culture ought to be informed by science and evidence, and perhaps adaptations can be made to certain cultural practices if we learn that they are harmful (to ourselves, to others, or to the environment). Sometimes the symbolic or esthetic value of a cultural practice can be preserved while the unhealthy aspects can be minimized.
-lots of high-fiber foods
-less meat, if any
-fish is healthy, especially fatty red fish such as salmon (an omega-3 source)
-but this has to be moderated due to the unfortunate risk of heavy metal contamination from eating a lot of fish, and due to the environmental problem of worldwide overfishing
-tea is good, in moderation (green & black), unless the caffeine is interfering with sleep
-dark chocolate is good for you; but it has to be in moderation, since it contains a lot of saturated fat
-carbohydrates (carbs) are probably important and necessary for mental health; low-carb ketotic diets are probably hard on the brain. But it is important to choose complex carbs that are released more gradually into your body. Sprouted whole grain breads are better. White bread or rice is almost like pure sugar, in terms of its rate of digestion into simple carbohydrates. Sugar itself should be cut down substantially (it has addictive properties; once you have gradually weaned sugar from cooking and baking, perhaps to 1/3 or 1/4 of what most recipes recommend, you will enjoy the intrinsic flavour of the baking more, and find the higher-sugar recipes unpleasantly sweet).
-components of the "Mediterranean" diet in which there is abundant use of olive oil, is probably healthy
-eliminate trans-fatty-acids from the diet (e.g. hydrogenated oils, often present in many packaged foods to prolong shelf life -- remember this may prolong the oil's "shelf life" on the inside of your arteries as well).
-there is some evidence that there is an excess of omega-6 fatty acids in the typical North American diet; this can be addressed by reducing use of omega-6 rich oils such as sunflower and corn oils, and instead using oils such as canola. Walnuts and flax are other natural sources of healthier omega-3 oils.
-1 to 2 glasses of wine (125-250 mL) per day may improve health compared to abstainers, and compared to those who drink more. But some individuals may have health problems as a result of drinking even small amounts of alcohol. In this case it is best to abstain.
-drinking water is great, but you really don't have to drink huge amounts. Keep yourself well-hydrated, but you only need to drink if you're thirsty.
-I do encourage people to leave all soft drinks behind -- the sugary ones are obviously bad for you. The ones with artificial sweeteners are probably not great for you either, and are also training you to expect sweetness while you hydrate yourself--this conditioning may exacerbate an unhealthy dependence upon simple carbohydrates and sweets, and cause you to be perceive the simple joy of drinking pure water to be unpleasantly mundane. Also do you really want to financially support the big soft-drink companies, with their expanding presence in children's schools, developing countries (many of whose people are dying from starvation), etc.?
-minimize the use of salt
-high-temperature cooking such as barbecuing adds flavour to food, but may result in higher levels of unhealthy chemicals, so it is probably best to reduce the intake of charred food.
-if you are a vegetarian or have other dietary restrictions, make sure you get an adequate intake of vitamins and minerals. A simple daily vitamin supplement should usually be sufficient. I do not see compelling evidence that "megadose" vitamins are beneficial.
-but there is some evidence that the RDA for vitamin D ought to be higher, perhaps up to 1000 IU per day or more.
-extra calcium supplementation may also be needed for many people on a long-term basis, to maintain bone health
While much of this advice is part of basic general health, I think that basic general health is also beneficial to mental health. And there may possibly be specific direct benefits to mental health from a very healthy diet.
I do qualify the above remarks, by saying that extremely clear, direct evidence linking healthy nutritional habits to improved mental health, is lacking. Much of the evidence is indirect or anecdotal. Many exaggerated claims are made in the advertising found in health-food stores. There are a few small studies looking at specific supplements, such as omega-3 supplements, which show some modest evidence that this can improve mood.
Some useful links:
1) the USDA nutrient database (detailed nutritional data about different foods):
http://www.nal.usda.gov/fnic/foodcomp/search/
2) the Cornell University food psychology page:
http://www.foodpsychology.cornell.edu/
The American Journal of Clinical Nutrition is a good academic journal to browse through, to get a good sense of what is going on in food & nutrition research. You can head to an academic library, and leaf through the past year's issues.
Addendum:
After reading the excellent comment on this entry, I feel compelled to add a few things to what I now recognize has been a very dry and pedantic set of comments:
I forgot to mention that I think food is one of the great joys and pleasures of life!
As with other joys, it is wonderful and healthy to develop and nurture a rich culinary experience.
Not only are food, cooking, and eating sources of sensual pleasure, they are also part of a rich and healthy culture (and a way to introduce oneself to new cultures), a part of a social and community life, and a part of an active intellectual life. It is a delight of human nature that we can start with something basic (e.g. an onion, or a grape), and keep refining it, transforming it, and using it in new ways, until we derive more and more art and pleasure from it. There is something very basic about the meaning of life itself in this kind of dynamic.
So I wholeheartedly endorse the idea of embracing and developing a rich culinary culture as part of healthy living. I do still maintain, however, that every culture ought to be informed by science and evidence, and perhaps adaptations can be made to certain cultural practices if we learn that they are harmful (to ourselves, to others, or to the environment). Sometimes the symbolic or esthetic value of a cultural practice can be preserved while the unhealthy aspects can be minimized.
Dietary Extremism
This is a sensitive topic, as many people feel badly about their weight, body image, and dietary habits. And many people have eating disorders, in which difficult relationships with food and with body image lead to a variety of behaviours that can do severe physical and emotional harm.
In this post, I wanted to address the specific phenomenon of what I call "dietary extremism". I consider the phenomenon to be similar to dogmatic religious belief.
Dietary extremism occurs as a result of people struggling to find some change in their lives that truly makes a difference for the better. They may have tried a wide variety of "standard routes" but continue to struggle with the same problems.
Extremism can often yield results for people, because it involves a radical change in lifestyle. It is something like joining a monastery. The lifestyle becomes more sustainable because of the community of fellow extremists (the other "monks in the monastery"), and because the community sets itself apart from the mainstream. The extremist beliefs are entrenched within the community, especially when members of the community are seeing significant changes within themselves for the first time.
Yet, the beliefs themselves are often extremely dogmatic and inaccurate. While I am a fan of permanent, positive life change, I believe that we must always stay attuned with the truth, always be open-minded to hear the facts, always be willing to question and challenge, always be wary of being told what to do by a guru-like figure (who, incidentally, may be making a lot of money and enjoying a lot of attention from fans, by selling books or running retreats).
A specific example that has come to my attention is the "raw food diet". Adherents have made substantial changes to their lifestyle. And, in my opinion, they are usually healthier for it. There is quite a bit of evidence that eating more fruits & vegetables, eating less meat, eating fewer animal products, etc. is part of good self-care. Furthermore, it is better for the environment, better to address world hunger (since raising animals instead of plants on agricultural land produces less nutritional energy per acre), and more humane (fewer sentient creatures need to be killed).
But most informational tracts about "raw food" are filled with claims that sound "scientific". The use of false or misleading pseudo-scientific claims is a typical tool used in charlatanism. This is one of the pathways that makes this potentially healthy dietary idea stultified by dogma. If you encounter statements about various types of nutritional degradation caused by heating, or about the miraculous virtues of some kind of oil (e.g. coconut oil), or about the advantages of choosing foods that are "less acidic", etc. I encourage you to be aware that there may be some dogmatic, charismatic salesmanship going on. The fact that these statements sound "scientific" may simply be fooling you. If you really want to know the truth, or what the evidence shows, then I think it is important to look closely yourself, at primary sources in reputable research journals.
The concern I have about the dogma doesn't necessarily mean that I think "raw food" (or some other diet) is a bad thing. I think it is a cultural practice, which has healthy aspects to it. Like other cultural practices, there may be a well-developed estheticism within it, leading, for example, to some really good recipes with raw food ingredients. The cultural practice crosses the line, though, into dogmatism, when it pronounces itself better than all other practices, and starts to support this claim using spurious or misleading information. All the while, many people are probably making quite a profit by marketing these ideas.
One of the phenomena often described in extremist groups is a collection of testimonial accounts from people whose lives have been radically changed for the better (e.g. cured of cancer, reached their ideal weight, felt healthy for the first time in their lives, etc.). While it may well be true that these individuals are genuinely thriving as a result of their new cultural practice, the mechanism of this change may be the result of very different factors than what they believe. Most any radical life change that leads to a sense of purpose, community, consistency, and meaning can have a transformative positive effect on an individual's health. I encourage such quests for purpose, community, and meaning -- but I encourage people to keep an open mind and to avoid dogma.
There are some good journals of scientific nutrition, such as the American Journal of Clinical Nutrition, and others. Abstracts are available on-line for free, and you can search on medical databases for information. Once again I encourage you to explore the evidence first-hand. When you read a claim about the nutritional virtues about this or that food, or this or that diet, be aware that you may be reading an ad, or an "info-mercial", and be prepared to search further yourself to clarify this kind of information before you make a needless change in your health behaviours.
In this post, I wanted to address the specific phenomenon of what I call "dietary extremism". I consider the phenomenon to be similar to dogmatic religious belief.
Dietary extremism occurs as a result of people struggling to find some change in their lives that truly makes a difference for the better. They may have tried a wide variety of "standard routes" but continue to struggle with the same problems.
Extremism can often yield results for people, because it involves a radical change in lifestyle. It is something like joining a monastery. The lifestyle becomes more sustainable because of the community of fellow extremists (the other "monks in the monastery"), and because the community sets itself apart from the mainstream. The extremist beliefs are entrenched within the community, especially when members of the community are seeing significant changes within themselves for the first time.
Yet, the beliefs themselves are often extremely dogmatic and inaccurate. While I am a fan of permanent, positive life change, I believe that we must always stay attuned with the truth, always be open-minded to hear the facts, always be willing to question and challenge, always be wary of being told what to do by a guru-like figure (who, incidentally, may be making a lot of money and enjoying a lot of attention from fans, by selling books or running retreats).
A specific example that has come to my attention is the "raw food diet". Adherents have made substantial changes to their lifestyle. And, in my opinion, they are usually healthier for it. There is quite a bit of evidence that eating more fruits & vegetables, eating less meat, eating fewer animal products, etc. is part of good self-care. Furthermore, it is better for the environment, better to address world hunger (since raising animals instead of plants on agricultural land produces less nutritional energy per acre), and more humane (fewer sentient creatures need to be killed).
But most informational tracts about "raw food" are filled with claims that sound "scientific". The use of false or misleading pseudo-scientific claims is a typical tool used in charlatanism. This is one of the pathways that makes this potentially healthy dietary idea stultified by dogma. If you encounter statements about various types of nutritional degradation caused by heating, or about the miraculous virtues of some kind of oil (e.g. coconut oil), or about the advantages of choosing foods that are "less acidic", etc. I encourage you to be aware that there may be some dogmatic, charismatic salesmanship going on. The fact that these statements sound "scientific" may simply be fooling you. If you really want to know the truth, or what the evidence shows, then I think it is important to look closely yourself, at primary sources in reputable research journals.
The concern I have about the dogma doesn't necessarily mean that I think "raw food" (or some other diet) is a bad thing. I think it is a cultural practice, which has healthy aspects to it. Like other cultural practices, there may be a well-developed estheticism within it, leading, for example, to some really good recipes with raw food ingredients. The cultural practice crosses the line, though, into dogmatism, when it pronounces itself better than all other practices, and starts to support this claim using spurious or misleading information. All the while, many people are probably making quite a profit by marketing these ideas.
One of the phenomena often described in extremist groups is a collection of testimonial accounts from people whose lives have been radically changed for the better (e.g. cured of cancer, reached their ideal weight, felt healthy for the first time in their lives, etc.). While it may well be true that these individuals are genuinely thriving as a result of their new cultural practice, the mechanism of this change may be the result of very different factors than what they believe. Most any radical life change that leads to a sense of purpose, community, consistency, and meaning can have a transformative positive effect on an individual's health. I encourage such quests for purpose, community, and meaning -- but I encourage people to keep an open mind and to avoid dogma.
There are some good journals of scientific nutrition, such as the American Journal of Clinical Nutrition, and others. Abstracts are available on-line for free, and you can search on medical databases for information. Once again I encourage you to explore the evidence first-hand. When you read a claim about the nutritional virtues about this or that food, or this or that diet, be aware that you may be reading an ad, or an "info-mercial", and be prepared to search further yourself to clarify this kind of information before you make a needless change in your health behaviours.
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