by Bonnie Kaplan, PhD & Julia Rucklidge, PhD

One thing that amazes us is that even though information linking nutrition to physical health is quite advanced, and generally very prominent in the media as well as in public awareness, people seem to be surprised when told that nutrients are essential for brain function. This disconnect is so great that we want to address it in today’s blog.

It may be silly to remind everyone of this, but we need to begin with this simple fact: the brain is part of the body. But to add some heft to this point, let us also recall that the brain is the organ of the body with the greatest metabolic demands (the heart is second).

What does it mean to say that the brain is metabolically the most demanding organ that we have? It means that even though the brain of an average adult is only 2% of his/her weight, that brain consumes at least 20% of the energy generated by that person’s mitochondria and various metabolic processes. And we all know that our energy is dependent on the quantity of nutrients that we consume.

So isn’t it interesting that more than 11 years ago, JAMA published the following statement: “…it appears prudent for all adults to take vitamin supplements”  [Fletcher & Fairfield, 2002]. This statement is in the abstract of the second part of an excellent 2-part article by Fairfield and Fletcher, which focused particularly on whether vitamin supplementation could reduce the risk of cardiovascular disease, common cancers (lung, colon, breast, and prostate), neural tube defects, and osteoporosis. Their answer was YES. They included 9 vitamins (no minerals) in their review, because of evidence that they are particularly important for physical (not mental) disease prevention in adults: folate, vitamins B6 and B12, vitamin D, vitamin E, the provitamin A carotenoids, vitamin A, vitamin C, and vitamin K.

We won’t review all their findings here because the focus of our blog is on mental disorders, and these two articles were entirely devoted to physical health, but you can download the scientific review for free here.

And you can download the second article, a clinically-applied commentary here.

In a nutshell, what they found in their review can be summarized in a few points:

Suboptimal levels of several vitamins are risk factors for cardiovascular disease, cancer, and osteoporosis.

Blood/serum levels are not reliable measures of suboptimal levels (as any nutrition researcher will tell you) for various reasons. One example they cite is a study that showed folate supplementation resulted in a significant decrease in serum homocysteine levels in a group of seniors who began the study with serum folate levels within the conventionally-accepted ‘normal’ range. So having a ‘normal’ level of a nutrient did not mean they were getting an optimal amount: supplementation still had a beneficial effect.

Many studies show low folate levels are associated with coronary heart disease and ischemic stroke. In fact, folate appears to be the key nutrient in determining plasma homocysteine levels, which is associated with inflammation and cardiovascular disease.

Folate supplementation has been associated with prevention of various types of cancers (especially colorectal and breast), although continued folate supplementation after a cancer diagnosis has been more controversial.

There are 3 ways to correct suboptimal levels of vitamin intake in the population: 1) Counsel patients to eat better (and your bloggers would add: and work on eliminating poverty so that they *can* eat better), 2) increase food fortification — we now have milk fortified with vit D, and many breads fortified with folate, and 3) take supplements.

Their conclusion was: “We recommend that all adults take one multivitamin daily” (and your bloggers would add: make sure your multivit has lots of minerals too). They also suggest that seniors take either two multivitamin tablets/day, or one multivit with additional B12 and D on the side.

So if your concern is cardiovascular disease, cancer, or osteoporosis, one really cheap, simple public health intervention would be to hand out supplements to the whole population.

Even at a simpler level of health, there are many clinical trials showing that vitamin and mineral supplements in communities of seniors (e.g., retirement homes, nursing homes) reduce flu, colds, and other communicable disease. So the bottom line is that in the realm of physical health, we have known for over a decade that everyone should be taking supplements.


Barringer TA, Kirk JK, Santaniello AC, Foley KL, Michielutte R., Effect of a multivitamin and mineral supplement on infection and quality of life. A randomized, double-blind, placebo-controlled trial. Ann Intern Med. 2003 Mar 4;138(5):365-71.

Fairfield KM, Fletcher RH. Vitamins for chronic disease prevention in adults: scientific review. JAMA. 2002 Jun 19;287(23):3116-26. Review. Erratum in: JAMA 2002 Oct 9;288(14):1720.

Fletcher RH, Fairfield KM. Vitamins for chronic disease prevention in adults: clinical applications. JAMA. 2002 Jun 19;287(23):3127-9.

First Published in Mad In America


Bonnie Kaplan, PhD. Bonnie has published on the biological basis of mental health – in particular, the contribution of nutrition to brain development and function, micronutrient treatments for mental disorders, and the effect of intrauterine nutrition on brain development and maternal mental health.
Julia Rucklidge, PhD. Julia’s interest in nutrition and mental illness grew out of her own research showing poor outcomes for children with psychiatric illness despite conventional treatments. She has been investigating the role of micronutrients in mental illness.


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