by Bonnie Kaplan, PhD & Julia Rucklidge, PhD
It is old knowledge that good nutrition is essential for mental health, and it is really old knowledge that improving nutrition can improve mental health. We would like to talk about the misguided approach of looking for a single nutrient that will have profound effects on brain function in isolation from other nutrients. Outside the realm of ‘common knowledge,’ and inside the somewhat rarefied air of academia, there have been many studies on the benefit gained from administering micronutrients to people with mental disorders, but almost all of those studies have been based on the ‘magic bullet model’ of treating with only one nutrient. When Bonnie and her colleagues set out to review the peer-reviewed studies in the scientific literature on the use of vitamins and minerals for the treatment of mood disorders (Kaplan et al., 2007), they found dozens of studies from about 1910 to the present. The range of nutrients studied was surprising: all the B vitamins, vitamins C, D, and E; calcium, chromium, iron, magnesium, zinc, selenium, choline, and more.
But here is the primary message that emerged from that examination of the literature: scientists were not studying nutrition in the way in which humans have evolved to require nutrients – consuming lots of them together and in balance. Studies generally followed what one might call the ‘drug trial model’: give a group of patients a single nutrient and see if their symptoms improve. A second review on nutrients for the treatment of Attention-Deficit/Hyperactivity Disorder (ADHD) revealed the same pattern – most studies on nutrients for the treatment of ADHD have involved one nutrient per study (Rucklidge et al., 2009).
Has the single nutrient approach yielded benefits? Actually, it has — but consistently modest benefits. There are studies showing that calcium supplementation modestly improves mood; that zinc or copper supplementation modestly improves mood and can improve attention; that various B vitamins administered one at a time modestly improve mood. This trend is visible in the present time, when our public funds have continued to support the magic bullet approach. For instance, recent research shows that omega-3s or vitamin D administered in isolation can improve some psychiatric symptoms, sometimes, in some studies. Yet to this day, in spite of the minimal returns from single-nutrient treatments, editorials in esteemed journals occasional promote the latest magic bullet nutrient to treat an illness.
We need to acknowledge that for some physical illnesses, single nutrient treatments can mean a matter of life or death. Scurvy is a great example of this: vitamin C can effectively prevent and also cure it. Prior to this discovery, it was commonplace to have an astounding 40% mortality rate of sailors on long voyages. And to be fair, there are a few examples of single nutrient treatments that have had powerful effects on mental health also. Niacin is a good example: pellagra and its psychosis can be cured with niacin therapy (more on that story in future blogs). Also, vitamin B12 can eradicate pernicious anemia, an illness that often presents with psychiatric symptoms.
But as a society, we seem to have a predisposition to thinking in terms of single ingredient solutions, which may be in part because this is the approach promoted by health professionals and the media. We have begun to see it as a natural product of the Post World War II ‘golden era’ of drug development. You have a systemic infection? Take an antibiotic – a single-ingredient pill. You have post-operative pain? Take a pain-killer – again, usually a single-ingredient pill. You have angina? Take a different, single-ingredient, magic pill. In terms of nutrition, what woman in the Western world, planning on getting pregnant, is unaware of the need to take folic acid to prevent neural tube defects in her offspring? We suspect few.
It has been hammered into us that folic acid is essential for prevention of congenital malformations (even though other B vitamins have also been shown to have at least a contributing effect). But how many midwives and physicians tell expectant mothers that there is also research showing that outcomes for children are potentially far better if the mother takes a broad-based nutrient formula? We have to wonder why this knowledge isn’t filtering through. We think it comes down to our intellectual minds having been trained to expect solutions from a single ingredient. Have drugs played a role in this expectation? We think so, based on the number of times when both of us have been asked, after presenting data on multinutrient treatments: “But… which is the active ingredient?”
The tendency of general society to think about single-substance magic bullets can also be attributed to what is often called The Scientific Method. Experimental science has made great progress in many areas by adhering to the principle that only one variable can be altered at a time, and all other variables must be simultaneously controlled. We are not so foolish as to question the value of the Scientific Method’s isolation of the ‘independent variable’ (IV) – but the question is this: why can’t the IV be complex? A few decades ago, psychologists declared that the IV can, indeed, be complex, and they have led the investigation of multi-variable, usually ‘manualized,’ treatments such as cognitive behavior therapy. The two of us, both trained in psychology, thought this debate was over: clearly there is a place for investigating complex IVs. But as recently as 6 months ago, one of Julia’s manuscripts was rejected by the leading American journal in the area of psychiatry with one reviewer complaining: “…it is impossible to know which among [the nutrients] may be an active ingredient with regard to any positive study findings.” Times have not changed much since one of the most senior psychiatrists in America informed Bonnie in about 2000 that no legitimate scientist would study more than one nutrient at a time.
What’s wrong with this single-nutrient literature? With precious few exceptions, all of it – hundreds of studies and millions of research dollars – has been wrongly based on the idea that a treatment must consist of just one nutrient at a time. The esteemed nutrition researcher Walter Mertz understood the fallacy in this way of thinking. Twenty years ago he declared that all of the single-nutrient diseases had likely been defined, and that all future discoveries of health-related nutrition would consist of complex nutrient formulas. Yet only in the last decade or so have studies of broad spectrum or complex nutrient treatments been carried out. And compared to the single nutrient research, this literature is sparse even though it makes physiological sense for nutrients to be most effective in combination. We hope our next blogs will convince you that broad based nutrient supplementation is the most logical way forward for the treatment of complex illness expressed in the various forms of dysregulated mood, obsessions, impulsivity, hallucinations, and scattered attention, to name a few. It seems outrageous to think that one nutrient could effectively resolve these constellations of symptoms.
Further reading, if you are interested:
Kaplan BJ, Crawford SG, Field CJ, Simpson JSA (2007). Vitamins, minerals, and mood. Psychological Bulletin, 133(5), 747-760.
Mertz, W. (1994). A balanced approach to nutrition for health: The need for biologically essential minerals and vitamins. Journal of the American Dietetic Association, 94, 1259–1262.
Rucklidge JJ, Johnstone J, Kaplan BJ. (2009). Nutrient supplementation approaches in the treatment of ADHD. Expert Review of Neurotherapeutics, 9, 461-76.
First published in Mad In America