Emily Deans, M.D.
Sun, 11 Nov 2012 04:00 CST
Vegetarian diets are correlated with an increase in mental health problems
Entirely vegan diets are unknown among traditional human cultures
Vegetarianism has been linked with higher rates of depression, anxiety, and particularly eating disorders (bingeing, restricting, and purging behaviors)
. Back in the early part of the 19th
century, dentist and explorer Weston Price went looking for vegans, but found only cannibals
*. Since vegan diets in nature
provide no vitamin B12 and very little in the way of usable long chain omega3 fatty acids
, it is not surprising that humans have continued to eat animals and animal-derived products. Nowadays one can obtain algae-derived DHA (the major long chain omega3 fatty acid present in the brain
) and supplement B12. That wasn't possible until a few years ago, and there's little evidence that supplementation with DHA alone is helpful for the brain
We have been encouraged to eat more plants and less animals
. Various writers have suggested it is healthier for our bodies and our planet. I have no objections to a mostly
as long as attention is paid to protein requirements and micronutrition. However, since little things in animal products (some essential like B12, some that can be created in our bodies but perhaps not in the amounts we need, such as creatine
) seem to be very important for the brain, it's interesting to look at the literature on vegetarian diets and mental health. Here is the latest (and the best) observational study: Vegetarian diet and mental disorders: results from a representative community survey
It's a German study, and for a large population-based retrospective observational design, it's actually fairly thorough and sensible. And if you are a vegetarian, it certainly doesn't say that vegetarianism causes
mental health problems. But in all but two studies done in the past, vegetarianism has been linked with higher rates of depression, anxiety, and particularly eating disorders (bingeing, restricting, and purging behaviors).
But to be perfectly honest, all those studies had some serious limitations (they were small, done special populations, and often measures based on just a few answers to general survey questions). I've reviewed a few
of them. (My favorite has to be the one
where they calculated arachidonic acid ingested to the hundredth of a gram based on data from a food frequency questionnaire, which seems very unlikely to be accurate) I don't think it is a coincidence that the two positive studies were done by the same group of researchers in the Seventh Day Adventist population.