"Determined" by Robert Sapolsky

 Robert Sapolsky is a great scientist with deep wisdom to share about humanity.  His recent book, Determined, is another must-read.  

The first half or so of the book details the many factors causing a given behaviour which are outside of what could be called "free will."  For example, hereditary factors, evolved traits, endocrine factors, social and cultural factors, childhood adversity, abuse, poverty, neglect, or discrimination, or on the other hand extreme enrichment through wealth and having good parents, home, and family; and the environmental conditions of the day or the hour.   Sapolsky reminds us, with evidence to back it up, how influential these factors are.  One chapter is dedicated to the Libet experiments, which demonstrate some degree of neural evidence of a decision before a person is subjectively aware of having decided, therefore calling into question whether our sense of making a decision is something like an illusion.  Other chapters are devoted to physics, such as about quantum mechanics and chaos theory; he argues that free will is not to be found in these areas.  

His strongest thesis, which he states a few times in the book, is that even if free will does exist, it is less influential than we believe it is -- that is, we underestimate the impact of other factors.  But often he strays from this strong thesis, into a state of denying the existence of any free will whatsoever, and then reflecting about the moral consequences of this.  

I think in many areas he is overconfident about findings that are quite debatable.  While the many genetic and environmental factors mentioned above are all indisputable, there could be a lot of debate (which he does not engage in) about the magnitude of some of these particular factors, or about the soundness or biases of the existing studies on these matters.  Just as in his previous book (also a great book), Behave, he quotes study data that really ought to be debated vigorously rather than accepted as the final truth on a matter.  In the current book, he even acknowledges these issues with Behave, but then he proceeds to do the same thing again anyways.  I'm not saying he's wrong about these claims, only that he overstates, at least through insinuation, the certainty of the evidence supporting them.  

 In quantum mechanics, for example, the most common view is that events in the quantum realm take place in a truly random fashion; such randomness eliminates the possibility of deterministic precision.   At the very least, there may be certain deterministic statements that are almost undeniably true (such as that you or I will die in less than 100 years; or that the sun will enter a red giant phase in several billion years), but there will always be a shadow of uncertainty around the specifics, or even the tiniest flicker of uncertainty about the event itself; some of this uncertainty is not due just to incomplete information to make a prediction, it is fundamental to physics itself.     Such quantum events I think are relevant to human events, as for example they could determine whether a particular DNA mutation takes place at a particular time, with very important consequences regarding an individual's survival, disease state, or passage of genes to the next generation.    Mind you, I discovered one group of physicists espousing an idea called "superdeterminism," which accounts for some of the peculiarities of quantum experiments (such as those dealing with Bell's inequality) by positing that apparently random quantum events are all completely determined, thus one cannot actually modify an experiment in a truly arbitrary manner, since the decision about the supposedly randomized experimental manipulation was already completely determined in advance.  Yet, I think we would have to agree that this is far from a settled matter in physics, and we would need to step back from making strong claims about this area.  

The strongest conclusion Sapolsky makes based on his thesis about determinism is that we therefore need to be more empathic and gently understanding about all human behaviour (of course, his thesis really takes away the possibility that we could somehow "choose" to be more understanding, since if this empathy occurred it all would have been determined in advance).  The best we could do to analyze this moral issue, while accepting his thesis of an absence of free will, is to consider an ideal moral code (in some kind of Platonic "realm of forms") which would have optimal fairness and justice.  This is in fact what moral codes, including those in the legal system, strive to do.  But in the light of our knowledge about free will, what changes if any would be best in terms of modifying moral or legal rules?  

He argues that dealing with criminal behaviour in a blaming or punitive manner is not rational, since the causes for crime have been determined not by the individual's "free will" but by genetic and environmental factors outside that person's control.  He similarly argues that praising people or celebrating great accomplishments is irrational, since the accomplishments, or capacity for hard work, etc. were also determined by factors outisde the individual's control.  So basically when we congratulate someone for a great accomplishment,  we are granting the person credit for factors that were really the product of millions of years of prior good luck.  

But of course, is this how we would really want to live?  To stop congratulating people after they do good things?  Or to always be meekly understanding when people do terrible things?  I agree with Sapolsky that improved scientific understanding about causality should prompt us to be more humble, and to be less inclined to reflexively blame or punish bad behaviour while motivated by reflexive emotions.   

But part of normal life involves congratulating people.  Admiring accomplishment is like admiring beauty in nature.   Maybe there should be a little bit of humble acknowledgement of those factors that contributed to the accomplishment outside of one's own "free will."  But this is part of the etiquette in almost any awards ceremony, though most people don't go into remote evolutionary causes for their good fortune--they tend to stop at family, friends, and teachers.  

Sapolsky cites various egregious examples of recklessly excessive violent punishments through history, leading to his own stance of advocating leniency in the justice system.  He has a very admiring tone around Norway's approach to having what most in the world would consider a shockingly lenient prison sentence for a notorious mass murderer.   While there is much to admire in Norway's civilization and justice system, I think this practice of strictly limited sentencing fails to address a massive component of consideration in criminal sentencing, which is the psychological impact of the sentence on victims, and families of victims (who are also victims) of the crime.  A reason to keep a mass murderer in custody permanently is to treat and prevent anxiety and distress among victims or families of victims.  It need not be motivated by our base (but highly evolved) urges to punish, or by irrational overestimation of subsequent criminal risk (scientific estimates of recidivism risk should obviously impact management of criminal offenders, though the accuracy of recidivism risk estimation is way less than 100%). It should definitely be influenced by considerations of the impact of the sentencing on the health and psychological well-being of victims.  

So all in all, a very important and impactful book.  I have to admit I find it disturbing to know that "free will" even if it does exist, is rather less complete in determining behaviour than most of us believe.   But in dealing with scientific findings, we need to be prepared to consider things if the evidence supports them, even if the findings might be disconcerting.

How does this book guide our understanding of mental health, or of therapies for mental health problems?  For one thing, we should be reminded to reflect on our tendency to be reflexively judgmental, or to blame people for what could be seen as failures of will.  If we do engage in judgment or blame, it should be guided by rationality, as to whether this would be helpful to improve the situation for all.  Often such blame or judgment is not actually helpful.  Arguably some forms of blame could be a normal motivational influence in humans, but probably we use this too often and too heavy-handedly.  

"The Power of Us" by Jay Van Bavel & Dominic Packer: a recommendation, review, and applications in psychiatry

 Jay Van Bavel and Dominic Packer are social psychologists whose recent book, The Power of Us, is a nice review of basic social psychology with a unique emphasis on the impact of identity and group affiliation on human behaviour and cognitive biases.  

This book would be an excellent accompaniment to The Righteous Mind, by Jonathan Haidt, and Blueprint, by Nicholas Christakis.   Haidt looks at individual differences in values as a factor affecting group behaviour.  For example, people who value loyalty and "purity" (as opposed to "compassion" or "fairness") as cardinal values may be more likely to have strong group adherence, and may be more accepting of hierarchical or paternalistic systems; such traits could lead in particular to involvement with conservative groups.   Haidt argues (and I strongly agree) that such values and traits have a strong hereditary basis (though are also partly influenced by environment & cultural milieu) and have evolved in humans due to selective advantages for those who have a strong inclination towards group affiliation.  But of course, too much loyalty can be a bad thing, if it causes people to adhere loyally to groups which are engaging in harmful behaviour--we see this problem in the news every day.    Christakis looks at group dynamics in an interesting mathematical way, with successful or unsuccessful group behaviour influenced by the structure of connectedness, which in turn is influenced by leadership styles, external factors,  and individual personality traits.  

The subject of group affiliation, identity, with associated biases, polarization, and conflict, is an incredibly important subject in the world today.  Group-based divisions arguably are a primary cause of political problems and war across the world, and lead to delays and inefficiencies in solving world problems such as poverty, environmental degradation, and war.  On the positive side, strong group allegiance has led to most of humanity's great achievements through history.  Most great accomplishments in the sciences, the arts, in politics, and in the law, involve large-scale collaboration.   

Group affiliation is a powerful source of identity for all of us.  If we have a strong attachment to a group, we are likely to favour ingroup members.   This is normal and ubiquitous,  but it can lead in an extreme case to hating or persecuting outgroup members.   To prevent this, it can be helpful to have a culture of interacting respectfully or collaboratively, or recreationally, with outgroup members (Jonathan Haidt made this point years ago, in The Righteous Mind).  It could be especially effective if any such recreational activity could blend members from different groups.  The authors cite some very successful examples of these ideas, such as having a soccer league in Iraq where each team was required to have players assigned equally from different conflicted religious groups.  The resulting games allowed each player, and each team, to like, respect, and enjoy outgroup members, since they became teammates,  leading to reduced conflict in their communities afterwards.  A famous example from classic social psychology research is the "Robbers Cave" experiment from the 1950s, in which antagonistic groups of teenage boys later worked together in friendship and harmony if they had to collaborate together to solve a problem external to them both.  

The chapter on "fostering dissent" is especially insightful.  The authors make the point that voicing a dissenting opinion within a group is socially costly.  Even if the dissent is about an important logical or moral issue, the risk of dissenting can be to make other group members angry, and therefore threaten one's position as a group member.  You risk being seen as disloyal or disrespectful.  They argue that you have to really care about your group to be willing to voice dissent.  I see this could often be true, but sometimes particular individuals are more oppositional or defiant, due to character traits, leading to frequent dissent even if they don't particularly care about their group status.  Another problem with dissent is that other group members may have quietly agreed with the dissenter's position, but it could be costly for them to endorse the dissent, since it could make them look bad or immoral for not having brought it up first.  So a default position in groups would be to maintain the status quo, and for dissent to be risky, even if the group is engaging in harmful behaviours or beliefs.   Unfortunately, this can cause harmful behaviour to be perpetuated in some groups, and for dissenters to be punished or ostracized.  Recent examples of this include U.S. politician Liz Cheney, who has spoken out against the deeply immoral behaviour in the leadership of her political party.  Unfortunately, she was defeated in the subsequent election.  While she should be seen as someone defending the honour, integrity, and values of her group, therefore protecting the group's long-term interests, she instead has been seen by her own ingroup members as disloyal, and punished for it.  I hope her own story is not over, and that her principled behaviour may prevail in the end.  

An approach to solving the dissent problem is to have a leadership structure or ethos in groups which encourages respectful disagreement, without fear of punishment or other consequences.  Also it is vitally important, as a persuasive factor, to frame dissent or challenge with the group's long-term well-being in mind--to remind others of the group's core values, of the group's long-term interests, with a dissenting view intended to be a service to the group rather than merely a criticism.  

On a larger scale, I think it is always helpful to expand the circle of our groups.  Instead of focusing on local or national or religious or political allegiances, why not focus on a shared humanity.  Some of the guiding insights of many of the world's religions, such as Christianity, were to expand a circle of love, respect, and inclusion to outgroup members, and not to shrink into insular, bitter enclaves judgmental of others outside of their own ranks.  

Psychiatric issues always exist in a social context.  Patients will always have group allegiances or identities.  These could involve religion, politics, gender, race, family, occupation, etc.  It is important to understand these group allegiances, empathize with them, and communicate therapeutic ideas with the group allegiances in mind.   Encouragement or advice for change carries a high risk of failing if it is expressed in such a way as to challenge a person's individual or group-based values.  A survey of group affiliation and identity factors should be an essential part of a psychiatric history, and an ongoing theme in a therapeutic dialogue.  

Foolproof, by Sander van der Linden: a recommendation, review, and analogy with psychotherapy

I strongly recommend a new book by Cambridge psychologist Sander van der Linden, entitled Foolproof: why misinformation infects our minds and how to build immunity.

I have followed van der Linden's research for several years, alongside other experts who are studying the psychology of persuasion, misinformation, and propaganda.    This area has been an interest of mine for many years, after discovering psychologists such as Cialdini and Kahneman.  

This is a subject that everyone needs to learn about!  Persuasive techniques (for good and for bad) have always been with us through history; the power and influence of these techniques will only continue to escalate, thanks to the internet era, and now the era of artificial intelligence (AI).  

I have discussed these issues in other posts, such as:

 Garth Kroeker: How Minds Change by David McRaney: a book review and discussion (August 18, 2022)

and 

Garth Kroeker: Political polarization, propaganda, conspiracy theories, misinformation, and vaccine hesitancy: a psychiatric approach to understanding and management).  (September 1, 2021) 

and 

Garth Kroeker: "GroupThink" (October 6, 2016) 

Van der Linden reviews the history and scope of misinformation.  Among the many current examples are conspiracy theorists impacting public opinion and policy, political influencers attempting to sway elections, propagandists from other countries defending violent or oppressive policies or sowing discord among their opponents, and of course the anti-vaccine community.  

There are a couple of acronyms he introduces: the word CONSPIRE can help us to recognize some of the common features of conspiracy theories:  

C = contradictory.  Most conspiracy theories feature contradictions.  For example, there could be a belief that some awful event is a hoax, but then also a belief that the awful event is real but was caused by evil conspirators.  

O = over-riding suspicion.    A sense of general distrust that goes beyond the topic of the conspiracy theory, particularly a distrust of official or mainstream explanations.  

N = nefarious plot.  A belief that there is a shadowy group of evildoers, such as government officials, corporations, or (at worst) a particular racial or ethnic group, who behind the scenes have caused some bad thing, perhaps with a motive to advance themselves.  

S = "something's wrong."  The belief that regardless of any acknowledged or corrected fact about an event, there's something going on that isn't right.  

P = persecuted individual.  The belief that someone is being deliberately harmed (most commonly, the believers in the conspiracy theory).  

I = immune to evidence.  Presentations of evidence often have little or no effect to change the opinion of people having conspiracy theory beliefs, in fact evidence could even "backfire" and cause the conspiracy theorist to become even more entrenched, or to believe that you or your sources of evidence are all biased or part of the conspiracy.   Such immunity to evidence is common among people who have limited expertise or knowledge about science, but could also be present in some highly educated people.  A conspiracy theorist who does have more scholarly expertise may understandably deploy statistical or psychological terminology to defend their beliefs; for example, by accusing other scholars of having psychological biases (such as confirmation bias).

Re = reinterpreting randomness.  This is creating a false causal story about random, unrelated events.   Humans in general are prone to doing this.   

It's interesting as a psychiatrist to reflect on the "CONSPIRE" factors above.  They are very often present in frank psychotic states, or in milder variants such as paranoid personality.  The tendency to have paranoid thoughts exists as a trait on a continuum in the population.  This trait has various environmental causes, but also has a high heritability.   It is a typical psychotic symptom to believe that there is a special, often ominous explanation behind pseudorandom events.    

Of course, sometimes there are explanations for events which differ from the mainstream understanding.  Through history there have always been maverick scientists,  who demonstrated something new and important, despite the objections or condemnation of their peers.  One example that has always bothered me was Alfred Wegener, who in 1912 was the first to propose the theory of continental drift; he was ridiculed and dismissed by his peers, who couldn't believe that entire continents could move across the face of the earth; Wegener tragically died before his theory was proved correct.   We have to be open to consider alternative theories.  However, maverick scientists, unlike conspiracy theorists, have clear evidence to support their claims; their reasoning does not contain contradictions; they are not immune to evidence, do not reinterpret randomness, and do not have ominous, over-riding suspicious beliefs about persecution.  

Van der Linden's next acronym is "DEPICT", to help remember features of manipulative communication:

  

D - discrediting.  The manipulative communicator will portray experts who disagree with them (such as scientific leaders, or even entire communities such as leading scientific journals), as biased, poorly qualified, incompetent, or having some nefarious agenda.  It is frustrating to have a scientific debate with someone who is engaging in such discrediting, since any sound evidence you raise with them will be dismissed as invalid.  

E - emotional.  Using strong emotional language to induce fear, anger, or disgust as a persuasive tool.  

P - polarization.  Framing issues, and people who have positions on these issues, in a "black or white" fashion, rather than as shades of grey.  This leads to a false sense of dichotomy, and encourages the formation of teams of opponents holding increasingly extreme positions, and increasing disrespect for those who disagree. 

I - impersonation.  Using fake experts to bolster a claim.   A variant of this is using an actual expert, but whose expertise has nothing to do with the issue at hand.  

C - conspiracy theories.  Encouraging conspiracy theory beliefs. 

T - trolling.  Attacking, insulting, or threatening opponents, usually in an online environment, such as on social media.  Such harassment has at times been so intense that scientists or policy experts (including in public health) have been afraid to speak out, fearing for their safety.  

Van der Linden's work focuses on how we can best deal with misinformation.  He concludes with an analogy:  misinformation must be dealt with by "immunizing" ourselves against it.  

In order to build immunity against an infectious disease, it is necessary to be exposed to a weakened version of the pathogen, in order to train the immune system, such that future doses of pathogens would be dealt with quickly.  

Infectious diseases are much easier to manage, with much less risk of harm or spread, by building immunity, rather than by only relying on treatment after infection.   

Similarly, it is much harder to "treat" misinformation after the fact.  Tactics to "treat" misinformation would be debate, education, and careful review of evidence.  But many people who have fallen into a misinformation "rabbit hole" are difficult to reach or persuade using reasoned debate.  Such debate may even cause the misinformed person to become even more angry or stubbornly adherent to their ideas.    

It is better to prevent people from falling into the rabbit hole in the first place--not by eliminating rabbit holes (which is impossible) but by teaching people how to identify and manage rabbit holes if they encounter them.  

The idea of "vaccination" is presented as an analogy throughout the book.  But beliefs and persuasion are not exactly like the body's immune system.  It's a very good analogy, but not perfect.  Much of the phenomenon van der Linden is talking about is explainable through learning theory:   we learn much better if we actually practice "hands on" with things, rather than just passively absorbing theory.  If you want to learn mathematics, you actually have to work through a lot of problems, not just read about how to do them.  If you want to learn how to ride a bike or drive a car, you have to practice cycling and driving, not just read about those things in a book!  As part of the practice, it is best to face challenging situations, and learn through experience how to overcome them.  

Similarly, to deal with emergencies, it is imperative to do behavioural practice many times as a preparation.  We have to do fire drills to prepare for a potential fire.  Pilots need to practice many times in a simulator how to manage engine failure.  If you only read about something, or learn about something, without practicing, you can't possibly become proficient, especially under pressure.  

To deal with misinformation, we have to practice, hands-on, dealing with misinformation, at first with "easy" examples, then more and more difficult ones.  

Applying these ideas to psychotherapy: CBT (cognitive-behavioural therapy) is very important and useful, but at worst it can be too passive.  Many people engaging in CBT do a lot of passive learning, they do written exercises in a workbook, but do not really practice deliberate exposure to uncomfortable stimuli.  The "vaccine" analogy could be useful to incorporate into CBT for treating depression or anxiety.   This is something that I have advocated for many years, mainly an emphasis on the "B" part of CBT.  To deal with panic attacks, it is most helpful to actually practice having panic attacks, in safe, controlled conditions!   To deal with depressive thoughts, it could be a useful exercise to invent simulated depressive thoughts, at first mild ones, then more challenging ones, to understand the mechanism by which they are created, and to practice facing them without being negatively affected.   This exposure therapy is like van der Linden's "vaccine."  But most therapists don't emphasize this enough, they only try to teach people to relax or cope with symptoms after they have occurred.  One of the purposes of talking about past emotional trauma is to recreate the painful events in the mind, but in a limited, controlled, "virtual" form, within the safe context of a therapy office.  In this way talking therapy has a vaccine-like effect.  

Linden's book is a must-read, not only for those interested in propaganda or misinformation, but also for anyone wanting a better understanding of the mind itself, with ideas that touch upon managing almost any life adversity, including mental illnesses.  

References: 

Linden, S. V. D. (2023). Foolproof: Why Misinformation Infects Our Minds and How to Build Immunity. WW Norton.

Why to get your COVID bivalent booster

The COVID vaccines have saved millions of lives, and spared millions more a frightening hospital or intensive care admission.   Many people may not realize that recovery from a COVID hospitalization will often not be complete; tissue damage from COVID pneumonia may not heal completely, also the psychological effect of respiratory failure should not be underestimated.  Severe respiratory failure (a terrifying, suffocating experience) can often be a cause of PTSD that could affect you psychologically for years afterwards.   The vaccines have caused a huge reduction in such episodes of respiratory failure.  

COVID vaccinations are not perfect, and their protective effect does diminish gradually with time, though does not disappear entirely.  There are indeed rare cases of serious adverse effects, much lower than the rate of similar or worse adverse effects from COVID itself.  Also, vaccination reduces the probability of spreading to other people, thereby multiplying the beneficial effects in the whole community.  Vaccination followed by a mild case of COVID a few months later likely adds robust protection compared to vaccination or infection alone.   But the most effective and safe protection is to have an updated bivalent COVID booster, particularly if your last dose of vaccine and any episode of COVID infection has been more than 2-3 months before present.  Unfortunately, fewer people have had their boosters compared to previous vaccine doses, resulting in thousands of needless hospitalizations and deaths.  

Anti-vaccine misinformation is widespread, with testimonial accounts from people claiming that the vaccines are harmful.  It is important to know that a bivalent booster will lead to a large reduction in risk of severe disease, hospitalization, ICU admission, and death.    Evidence to support this is very, very robust, and unfortunately has not been emphasized strongly enough in current public health information campaigns.  

I encourage perusing the references below.  Aside from reading the studies and assessing the evidence for yourself, I encourage you to look up the authors and verify for yourself that these are incredibly experienced, well-educated researchers from major research centers, with no major biases or profit motives affecting their findings.    The research findings are corroborated and consistent with the  experience of ICU and infectious disease physicians, who on a daily basis in the past months have continued to see much more severe COVID disease and dangerously high hospital occupancy among those who are not up-to-date with their booster vaccinations.  

The references below are a preliminary list; I encourage you to continue checking out other references I've included in my previous COVID-related posts.  

References

Watson, O. J., Barnsley, G., Toor, J., Hogan, A. B., Winskill, P., & Ghani, A. C. (2022). Global impact of the first year of COVID-19 vaccination: A mathematical modelling study. The Lancet Infectious Diseases, 22(9), 1293–1302. https://doi.org/10.1016/S1473-3099(22)00320-6

CDC. COVID Data Tracker.  Centers for Disease Control and Prevention. 

https://covid.cdc.gov/covid-data-tracker/#vaccine-effectiveness

https://covid.cdc.gov/covid-data-tracker/#rates-by-vaccine-status

Arbel, R., Peretz, A., Sergienko, R., Friger, M., Beckenstein, T., Yaron, S., Hammerman, A., Bilenko, N., & Netzer, D. (2023). Effectiveness of the Bivalent mRNA Vaccine in Preventing Severe COVID-19 Outcomes: An Observational Cohort Study (SSRN Scholarly Paper No. 4314067). https://doi.org/10.2139/ssrn.4314067

https://www.azdhs.gov/covid19/documents/data/rates-of-cov-19-by-vaccination.pdf?v=2023010

Lin, D.-Y., Xu, Y., Gu, Y., Zeng, D., Wheeler, B., Young, H., Moore, Z., & Sunny, S. K. (2023). Effectiveness of Vaccination and Previous Infection Against Omicron Infection and Severe Outcomes in Children Under 12 Years of Age (p. 2023.01.18.23284739). medRxiv. https://doi.org/10.1101/2023.01.18.23284739

Andersson, N. W., Thiesson, E. M., Baum, U., Pihlström, N., Starrfelt, J., Faksová, K., Poukka, E., Meijerink, H., Ljung, R., & Hviid, A. (2023). Comparative effectiveness of the bivalent BA.4-5 and BA.1 mRNA-booster vaccines in the Nordic countries (p. 2023.01.19.23284764). medRxiv. https://doi.org/10.1101/2023.01.19.23284764

Davydow, D. S., Gifford, J. M., Desai, S. V., Needham, D. M., & Bienvenu, O. J. (2008). Posttraumatic stress disorder in general intensive care unit survivors: A systematic review. General Hospital Psychiatry, 30(5), 421–434. https://doi.org/10.1016/j.genhosppsych.2008.05.006

Tenforde, M.W. et al. (2022). Early estimates of bivalent mRNA vaccine effectiveness in preventing COVID-19-associated emergency department or urgent care encounters and hospitalizations among immunocompetent adults. VISION Network, nine states, Sep-Nov 2022.  Morbidity and Mortality Weekly Report, 71(5152), 1616-1624. 

Heavy Metals in Chocolate

 Chocolate is one of my favourite foods, and may even have health benefits.  But of course, we have to be wary of bias about health claims that we would really, really love to be true!  

 A few studies suggest possible positive mood effects from chocolate consumption, but this research looks a little bit preliminary or questionable (Shin et al).   

Other studies suggest that dark chocolate could help reduce blood pressure (see Amoah et al for a meta-analysis).  

But a recent simple RCT showed that 8 weeks of dark chocolate intake (100 mg per day) did not affect cognition (Suominen et al). 

In any case, I think chocolate, like other delicious foods, has a role in a healthy, happy lifestyle, provided of course that we stick to moderation, and that we choose products which are high quality and lower in sugar.  

The big issue in the past few weeks has been concern that chocolate contains high levels of lead and cadmium.  This was alarming to read about.  The December 2022 Consumer Reports article on this showed that many brands of dark chocolate (including my own personal favourite) contain up to  7 micrograms of cadmium and 1 microgram of lead in a typical 1-ounce serving.    They compare these numbers to California's maximum allowable dose levels, which are 4 micrograms of cadmium per day, and 0.5 micrograms of lead.    

But whenever we see a report like this, it would be important always to find out what the baseline levels are in the population, otherwise we may be much more alarmed than we need to be.  Various studies have looked at average lead and cadmium intake in the diet.   In summary, average cadmium intake in the diet ranges from 5 micrograms per day in the U.S.,  to 10-15 micrograms per day in Europe, to 30 micrograms per day in Asia, from sources such as grains, nuts, vegetables, and shellfish.  Average lead intake ranges from 2-5 micrograms per day in the U.S., to 10-30 micrograms per day in Europe and other parts of the world, from sources such as cereals, meat, and fish.  Recommendations from various sources, such as the FDA, conclude a conservative safe limit of about 58 micrograms a day for cadmium and 12.5 micrograms a day for lead, for a typical 70 kg adult, which are numbers much lower than previous recommendations. 

So the 7 micrograms of cadmium and 1 microgram of lead in a serving of chocolate is still way below most recommended safe limits, and in a ballpark comparable to existing average dietary intakes across the world.  

Of course, any amount of lead and cadmium should be reduced or eliminated in the diet.  And I hope that chocolate makers will take steps to bring down these levels.  But in the meantime, moderate daily chocolate intake is very unlikely to push your lead or cadmium levels up very much higher than they would have been otherwise; the enjoyment and possible health benefits very likely exceed the small risks.  

It will continue to be a longer-term global issue to minimize heavy metal contamination and other contaminants in food and water.  While some of this contamination is "natural," other examples are made worse by industrial pollution.  In any case, there is more work to be done to improve food safety in the coming decades.  

References:

Suominen, M. H., Laaksonen, M. M. L., Salmenius-Suominen, H., Kautiainen, H., Hongisto, S.-M., Tuukkanen, K., Jyväkorpi, S. K., & Pitkälä, K. H. (2020). The short-term effect of dark chocolate flavanols on cognition in older adults: A randomized controlled trial (FlaSeCo). Experimental Gerontology, 136, 110933. https://doi.org/10.1016/j.exger.2020.110933

Amoah, I., Lim, J. J., Osei, E. O., Arthur, M., Tawiah, P., Oduro, I. N., Aduama-Larbi, M. S., Lowor, S. T., & Rush, E. (2022). Effect of Cocoa Beverage and Dark Chocolate Consumption on Blood Pressure in Those with Normal and Elevated Blood Pressure: A Systematic Review and Meta-Analysis. Foods, 11(13), Article 13. https://doi.org/10.3390/foods11131962

Shin, J.-H., Kim, C.-S., Cha, L., Kim, S., Lee, S., Chae, S., Chun, W. Y., & Shin, D.-M. (2022). Consumption of 85% cocoa dark chocolate improves mood in association with gut microbial changes in healthy adults: A randomized controlled trial. The Journal of Nutritional Biochemistry, 99, 108854. https://doi.org/10.1016/j.jnutbio.2021.108854

Lead and Cadmium Could Be in Your Dark Chocolate. (2022, December 15). Consumer Reports. https://www.consumerreports.org/health/food-safety/lead-and-cadmium-in-dark-chocolate-a8480295550/

Cadmium and Lead Exposure. (n.d.). Retrieved January 29, 2023, from https://encyclopedia.pub/entry/2829

Koch, W., Czop, M., Iłowiecka, K., Nawrocka, A., & Wiącek, D. (2022). Dietary Intake of Toxic Heavy Metals with Major Groups of Food Products—Results of Analytical Determinations. Nutrients, 14(8), 1626. https://doi.org/10.3390/nu14081626