There is some evidence that antidepressants, particularly the serotonin reuptake inhibitors, can reduce bone density, and increase the risk of fractures. This risk would be most pertinent in an elderly population.
Serotonin is a relevant factor in bone metabolism, so it is important to consider the potential impact of serotonergic antidepressants on bone health.
Here's a study showing an association between depression and reduced bone mineral density. Depression itself is an understandable cause for bone mineral loss, since it is associated with fatigue, therefore less exercise, worse nutrition, and increased stress hormones such as corticosteroids. In this study, antidepressant use was independently associated with bone mineral density loss in women. It is a retrospective analysis from a large catchment area study involving over 1000 people, who were followed since 1981.
http://www.ncbi.nlm.nih.gov/pubmed/19126857
There are some other studies showing an association between antidepressant use (especially SSRIs) and fractures due to fragile bone. One of the better such studies was published in 2008, looking at the incidence of fractures in a large population-based cohort involving 7983 people aged 55 and over. Importantly, the authors attempted to control for the impact of depression itself on fracture incidence, and basically showed that current SSRI use approximately doubles the risk of fractures:
http://www.ncbi.nlm.nih.gov/pubmed/18626268
There is one important prospective animal study, which shows a small effect of SSRI treatment on bone quality over a 6-month period:
http://www.ncbi.nlm.nih.gov/pubmed/17163489
In conclusion, it is important to know that antidepressants could possibly reduce bone density, and therefore contribute to an increased risk of fractures in the elderly. If antidepressant therapy is needed, it is especially important to encourage activities which protect bone health, such as regular exercise, and good nutrition (including ample calcium and vitamin D in the diet). Non-SSRI antidepressants such as tricyclics may have a smaller effect than the SSRIs. Bone density testing could be indicated, as could medication treatments to protect bone mineralization. These issues should be discussed with your family physician and your psychiatrist.
Thursday, May 21, 2009
Thursday, May 7, 2009
Long-term stimulants & ADHD
The long-term use of stimulants such as methylphenidate (Ritalin), dextroamphetamine (Dexedrine), and mixed amphetamine salts (Adderall), in the treatment of attention or behaviour problems in children and adults, has been a controversial issue.
Symptoms of so-called ADHD include inability to sustain attention while doing academic, social, domestic, or work activities; restlessness, and inability to sit quietly or wait patiently. Of course, everyone has difficulties in these domains at times. The diagnosis of ADHD is intended to apply to individuals whose symptoms are so severe in these areas that it causes serious, ongoing problems functioning socially, academically, and with other life tasks. Those with an ADHD diagnosis are much more likely to drop out of school, to be unable to maintain jobs, to have difficulty maintaining friendships, and to have conduct problems ultimately leading to problems with the law, etc.
It is abundantly clear, from careful research, that stimulants improve symptoms of ADHD, and associated problems with social behaviour and disordered conduct.
I do not see good evidence that stimulants adversely affect personality traits or sense of self. Rather, in many cases, the experience of having severe untreated ADHD symptoms adversely affects personality traits and sense of self.
I will add to this post later, to discuss potential adverse effects from stimulant therapy. But stimulants are generally well-tolerated, with a low risk of serious adverse effects for most people.
Existing psychosocial treatments can help ADHD symptoms as well, but they do not work as well as stimulants, and--surprisingly--combining psychosocial treatments with stimulant therapy does not work much better than stimulants alone, except possibly for some individual cases. Here is some evidence, from a 2008 meta-analysis, for this finding:
http://www.ncbi.nlm.nih.gov/pubmed/18068284
Here are a few other important studies pertaining to long-term stimulant use:
This 5 year prospective study shows that stimulant therapy substantially reduces the rate of smoking and substance use disorders in adolescents with ADHD:
http://www.ncbi.nlm.nih.gov/pubmed/18838643
About 20% of ADHD adolescents treated with stimulants over 5 years developed a substance use disorder, compared to 55% of ADHD adolescents not treated with stimulants.
Stimulant-treated adolescents also had much lower rates of smoking. This is a very strong and compelling study, showing profound reductions in addictive disorders as a result of long-term stimulant treatment.
This 2008 study looked at a group of 169 children with ADHD, and followed up on them 9 years later:
http://www.ncbi.nlm.nih.gov/pubmed/18928410
The children who had taken stimulant treatment for their ADHD fared better than those with ADHD who had not taken stimulants, in terms of academic performance (as measured in several different ways). Neither ADHD group performed as well as a comparison group without ADHD.
This 2007 study from the Journal of Developmental and Behavioral Pediatrics is particularly strong, in that it looks at an entire birth cohort (all 5718 children born in Rochester between 1976-1982, of whom 370 with ADHD were identified):
http://www.ncbi.nlm.nih.gov/pubmed/17700079
It looked at long-term outcomes, over an average of 18 years. The study shows reduced absenteeism, reduced likelihood of being held back a grade, and slightly higher reading test scores, for ADHD children receiving long-term stimulant therapy.
Reading scores were particularly higher in the children who had received high doses of stimulants for longer periods of time.
The stimulant group did not differ from the non-stimulant group with respect to sociodemographic variables or duration of follow-up. The study was retrospective and was not randomized, yet it remains a very strong piece of evidence about long-term effects of stimulant treatment for ADHD.
I think these findings emphasize a number of things:
1) stimulants work very well for ADHD symptoms
2) stimulants unfortunately only have a slight effect on long-term academic outcomes
3) existing psychosocial treatments work modestly well on their own, but for most people do not add to the benefits of stimulants. The psychosocial treatments did not improve long-term academic outcomes. The duration of psychosocial treatment did not correlate with better improvement in symptoms, so the weakness of existing psychosocial treatments is not likely due to inadequate length of treatment.
4) long-term stimulant therapy may substantially reduce the risk of ADHD kids getting into alcohol use, substance use, or smoking problems. This finding is strong evidence against the idea that stimulant use increases the risk for subsequent addictive disorders.
I do think we need to keep working on better psychosocial treatments. I suspect that intensive, long-term, individualized treatment, with a style which suits the personality and strengths of each person, will be most effective. And I suspect that such treatments would need to be combined with positive, supportive milieux at home, school, work, and in peer relationships.
I will add to this post, or write a sequel post, to discuss other treatments for ADHD, such as atomoxetine, antidepressants, EEG biofeedback, dietary modification, and some newer psychosocial treatment ideas.
Symptoms of so-called ADHD include inability to sustain attention while doing academic, social, domestic, or work activities; restlessness, and inability to sit quietly or wait patiently. Of course, everyone has difficulties in these domains at times. The diagnosis of ADHD is intended to apply to individuals whose symptoms are so severe in these areas that it causes serious, ongoing problems functioning socially, academically, and with other life tasks. Those with an ADHD diagnosis are much more likely to drop out of school, to be unable to maintain jobs, to have difficulty maintaining friendships, and to have conduct problems ultimately leading to problems with the law, etc.
It is abundantly clear, from careful research, that stimulants improve symptoms of ADHD, and associated problems with social behaviour and disordered conduct.
I do not see good evidence that stimulants adversely affect personality traits or sense of self. Rather, in many cases, the experience of having severe untreated ADHD symptoms adversely affects personality traits and sense of self.
I will add to this post later, to discuss potential adverse effects from stimulant therapy. But stimulants are generally well-tolerated, with a low risk of serious adverse effects for most people.
Existing psychosocial treatments can help ADHD symptoms as well, but they do not work as well as stimulants, and--surprisingly--combining psychosocial treatments with stimulant therapy does not work much better than stimulants alone, except possibly for some individual cases. Here is some evidence, from a 2008 meta-analysis, for this finding:
http://www.ncbi.nlm.nih.gov/pubmed/18068284
Here are a few other important studies pertaining to long-term stimulant use:
This 5 year prospective study shows that stimulant therapy substantially reduces the rate of smoking and substance use disorders in adolescents with ADHD:
http://www.ncbi.nlm.nih.gov/pubmed/18838643
About 20% of ADHD adolescents treated with stimulants over 5 years developed a substance use disorder, compared to 55% of ADHD adolescents not treated with stimulants.
Stimulant-treated adolescents also had much lower rates of smoking. This is a very strong and compelling study, showing profound reductions in addictive disorders as a result of long-term stimulant treatment.
This 2008 study looked at a group of 169 children with ADHD, and followed up on them 9 years later:
http://www.ncbi.nlm.nih.gov/pubmed/18928410
The children who had taken stimulant treatment for their ADHD fared better than those with ADHD who had not taken stimulants, in terms of academic performance (as measured in several different ways). Neither ADHD group performed as well as a comparison group without ADHD.
This 2007 study from the Journal of Developmental and Behavioral Pediatrics is particularly strong, in that it looks at an entire birth cohort (all 5718 children born in Rochester between 1976-1982, of whom 370 with ADHD were identified):
http://www.ncbi.nlm.nih.gov/pubmed/17700079
It looked at long-term outcomes, over an average of 18 years. The study shows reduced absenteeism, reduced likelihood of being held back a grade, and slightly higher reading test scores, for ADHD children receiving long-term stimulant therapy.
Reading scores were particularly higher in the children who had received high doses of stimulants for longer periods of time.
The stimulant group did not differ from the non-stimulant group with respect to sociodemographic variables or duration of follow-up. The study was retrospective and was not randomized, yet it remains a very strong piece of evidence about long-term effects of stimulant treatment for ADHD.
I think these findings emphasize a number of things:
1) stimulants work very well for ADHD symptoms
2) stimulants unfortunately only have a slight effect on long-term academic outcomes
3) existing psychosocial treatments work modestly well on their own, but for most people do not add to the benefits of stimulants. The psychosocial treatments did not improve long-term academic outcomes. The duration of psychosocial treatment did not correlate with better improvement in symptoms, so the weakness of existing psychosocial treatments is not likely due to inadequate length of treatment.
4) long-term stimulant therapy may substantially reduce the risk of ADHD kids getting into alcohol use, substance use, or smoking problems. This finding is strong evidence against the idea that stimulant use increases the risk for subsequent addictive disorders.
I do think we need to keep working on better psychosocial treatments. I suspect that intensive, long-term, individualized treatment, with a style which suits the personality and strengths of each person, will be most effective. And I suspect that such treatments would need to be combined with positive, supportive milieux at home, school, work, and in peer relationships.
I will add to this post, or write a sequel post, to discuss other treatments for ADHD, such as atomoxetine, antidepressants, EEG biofeedback, dietary modification, and some newer psychosocial treatment ideas.
Monday, May 4, 2009
Direct personal requests for help
I encourage all of you who might be searching for help, waiting for help, or struggling with existing help, to be patient, to be brave, to hold onto hope.
At times I have had some direct personal requests for help from individuals who are not currently my patients. I feel that I have to stick to a policy of not being able to respond directly to such requests, as I feel that a direct response would, for me, cause me to feel a professional duty to maintain ongoing care.
But, once again, I do encourage all those who are struggling to hold on, to be patient, to be brave, to be open-minded about your options for new things to try, to hold onto hope.
For those in the Vancouver area, I remind you of some of the local resources:
http://garthkroeker.blogspot.com/2008/12/finding-help.html
If local resources are failing to keep you afloat, please keep an open mind about using emergency services, such as the local hospital emergency rooms.
At times I have had some direct personal requests for help from individuals who are not currently my patients. I feel that I have to stick to a policy of not being able to respond directly to such requests, as I feel that a direct response would, for me, cause me to feel a professional duty to maintain ongoing care.
But, once again, I do encourage all those who are struggling to hold on, to be patient, to be brave, to be open-minded about your options for new things to try, to hold onto hope.
For those in the Vancouver area, I remind you of some of the local resources:
http://garthkroeker.blogspot.com/2008/12/finding-help.html
If local resources are failing to keep you afloat, please keep an open mind about using emergency services, such as the local hospital emergency rooms.
Friday, May 1, 2009
My Experiences with Industry Sponsorship
Around 2001, when I was a mood disorders fellow, I was asked to do an educational lecture by Organon, the manufacturer of the antidepressant mirtazapine. The company clearly wanted one of the more prominent mood disorders research psychiatrists to do the lecture--but since no one else was available, they settled for me. It was common practice for research psychiatrists or other perceived "leaders in the field" to be paid by drug companies for "educational lectures" attended by family physicians or other psychiatrists, usually at expensive restaurants or lavishly-catered hotel conference rooms (the drug company footing the bill, of course); I think this common practice remains. To be fair, I think everyone assumed that this was all fine, even a useful educational service. Probably many of those involved in this practice still believe that. And perhaps many of these lectures are useful educational services to some degree, it's just that both the lecturers and the recipients may be unaware of the biases involved. Anyway, my lecture was supposed to be about treating resistant depression. I was provided by the company rep with numerous powerpoint slides about mirtazapine to include in my lecture. I did the lecture, and was paid generously for it. I included a few of the slides about mirtazapine, but I truly tried to give a lecture broadly about treating resistant depression, and discussed mirtazapine for only about 20% of the talk. Clearly the company rep was not impressed with my performance, and I was never again asked to do a lecture for them. I'm glad of that, since the more one does these things, the more one can be convinced that it is professionally appropriate, despite the obvious biases involved.
Around 2000-2001 I was involved in a clinical study of a new drug. The drug company sponsored the study, flew everyone business-class to Monaco (on the French Riviera), and put us up in a lavish 5-star hotel, to attend an introductory meeting regarding the study. Such meetings, in my opinion, are utterly needless expenses. Introductions and instructions about a study can be done without transcontinental travel. Training for rating scales, etc., could be done in some other simple, standardized way, without any need for travel. I did enjoy the trip, and I wouldn't doubt that it contributed to my having a more favourable view of that company's products in the following years.
Also around 2000-2001 I was involved in another clinical study. The drug company, also sponsoring the study, flew everyone business-class to Miami, Florida, and put us up in a famous 5-star hotel. By this time I was starting to have more questions about the neutrality of the research, under these circumstances. Something that struck me during that trip was my observations of the company reps meticulously preparing their video presentation for us -- they were preparing a show; it was basically a slick info-mercial, sound-effects and all. I was also struck by the fact that no one around me seemed to notice this or have a critical view of it. I felt like, on the one hand, we were being treated like royalty, but on the other hand we were simply being bought. I realize that it is good for companies to make participation in research projects attractive to everyone involved. It can be frustrating work to recruit patients for clinical studies, and many psychiatrists would rather not take time away from other aspects of work to participate in research. Research is important, and maybe travel & adventure could be fair aspects to enjoying the life of a researcher. BUT -- the travel is really not necessary at all. It is an extravagance. Information and training about a research protocol can happen locally. Other communication can happen over the phone, over the net, or over a video link. The other expensive extravagances just reduce the neutrality of the study, and also bias all participants (many of whom are "leaders in the field" who often influence other practitioners) to have and convey a more favourable view of the company's products, irrespective of the results of the particular study.
I think it would be interesting to have disclosures in research papers not only about the authors' affiliations with, or income received from, the drug companies, but also about the travel expenses paid by the companies for meetings pertaining to the study in question.
A more mundane aspect of industry sponsorship, during my residency between 1995-2000, was the weekly phenomenon of the "drug lunch." Basically, during almost every group meeting or rounds, food would be provided by a drug rep--usually quite a tasty lunch.
A continuing aspect of industry sponsorship is the distribution of free samples. At times I find this quite useful, to help someone get started on something right away, without the time or expense of a pharmacy visit. At other times, people have not been able to afford medication (the most common psychiatric medications are available for free in BC, through a government plan, but many more exotic medications are not covered by this plan): in some cases, the drug companies have provided a free "compassionate release" supply of medication for extended periods of time. Yet, I recognize that these phenomena lead to bias. The presence of a particular sample can influence the choice of which particular medication to recommend, particularly when the different choices are all similarly effective.
I realize this post may come off sounding like some kind of anti-corporate rant. I don't want to slam corporations too much though -- thanks to large companies, we have many more treatments which can profoundly improve quality of life, and which can save many lives. Profit-oriented motivations can drive productivity, competition, and better research. It's just that we can't be swept into the current of advertising and other biased persuasive tactics which companies use to sell more of their products. We can sympathize with the reality that companies behave this way, but as health care professionals, or as individuals contemplating whether or not to take a particular medication or other treatment, we need to have information which is clear, unbiased, as objective as possible.
Around 2000-2001 I was involved in a clinical study of a new drug. The drug company sponsored the study, flew everyone business-class to Monaco (on the French Riviera), and put us up in a lavish 5-star hotel, to attend an introductory meeting regarding the study. Such meetings, in my opinion, are utterly needless expenses. Introductions and instructions about a study can be done without transcontinental travel. Training for rating scales, etc., could be done in some other simple, standardized way, without any need for travel. I did enjoy the trip, and I wouldn't doubt that it contributed to my having a more favourable view of that company's products in the following years.
Also around 2000-2001 I was involved in another clinical study. The drug company, also sponsoring the study, flew everyone business-class to Miami, Florida, and put us up in a famous 5-star hotel. By this time I was starting to have more questions about the neutrality of the research, under these circumstances. Something that struck me during that trip was my observations of the company reps meticulously preparing their video presentation for us -- they were preparing a show; it was basically a slick info-mercial, sound-effects and all. I was also struck by the fact that no one around me seemed to notice this or have a critical view of it. I felt like, on the one hand, we were being treated like royalty, but on the other hand we were simply being bought. I realize that it is good for companies to make participation in research projects attractive to everyone involved. It can be frustrating work to recruit patients for clinical studies, and many psychiatrists would rather not take time away from other aspects of work to participate in research. Research is important, and maybe travel & adventure could be fair aspects to enjoying the life of a researcher. BUT -- the travel is really not necessary at all. It is an extravagance. Information and training about a research protocol can happen locally. Other communication can happen over the phone, over the net, or over a video link. The other expensive extravagances just reduce the neutrality of the study, and also bias all participants (many of whom are "leaders in the field" who often influence other practitioners) to have and convey a more favourable view of the company's products, irrespective of the results of the particular study.
I think it would be interesting to have disclosures in research papers not only about the authors' affiliations with, or income received from, the drug companies, but also about the travel expenses paid by the companies for meetings pertaining to the study in question.
A more mundane aspect of industry sponsorship, during my residency between 1995-2000, was the weekly phenomenon of the "drug lunch." Basically, during almost every group meeting or rounds, food would be provided by a drug rep--usually quite a tasty lunch.
A continuing aspect of industry sponsorship is the distribution of free samples. At times I find this quite useful, to help someone get started on something right away, without the time or expense of a pharmacy visit. At other times, people have not been able to afford medication (the most common psychiatric medications are available for free in BC, through a government plan, but many more exotic medications are not covered by this plan): in some cases, the drug companies have provided a free "compassionate release" supply of medication for extended periods of time. Yet, I recognize that these phenomena lead to bias. The presence of a particular sample can influence the choice of which particular medication to recommend, particularly when the different choices are all similarly effective.
I realize this post may come off sounding like some kind of anti-corporate rant. I don't want to slam corporations too much though -- thanks to large companies, we have many more treatments which can profoundly improve quality of life, and which can save many lives. Profit-oriented motivations can drive productivity, competition, and better research. It's just that we can't be swept into the current of advertising and other biased persuasive tactics which companies use to sell more of their products. We can sympathize with the reality that companies behave this way, but as health care professionals, or as individuals contemplating whether or not to take a particular medication or other treatment, we need to have information which is clear, unbiased, as objective as possible.
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
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