The recent article in Women’s Health Magazine about the “scary mental health risks” associated with meatless diets has—not surprisingly—received lots of attention. People love to hear bad news about vegetarian and vegan diets, after all.
Author Jill Waldbieser pulled the article together from the usual hodgepodge of questionable resources—in this case a few anecdotes plus comments from Vegetarian Myth author Lierre Keith. She also referenced two studies, one in Australia and one in Germany.
I took a quick peek at the German study, which assessed diet and mental health in a group of about 4100 subjects.(1) Subjects who said they were vegetarian or predominantly vegetarian were 15% more likely to report depressive disorders. But they were also likely to have adopted their vegetarian diet after developing depression. The researchers concluded that being vegetarian did not cause people to be depressed. Rather depressed people—for whatever reason—were more likely to choose a vegetarian diet.
It’s also worth noting that vegetarians in this study were people who said they eat no meat or very little meat. The German word for meat doesn’t include poultry, so it’s not at all clear that all of these “vegetarian” subjects actually ate a vegetarian diet.
I couldn’t find the Australian study that was mentioned in the Women’s Health article. It appears to be an unpublished survey, and the lead investigator reached the same conclusion as the German researchers—that depressed people are more likely to adopt vegetarian diets.
So there you have it—the case for mental health risks of a vegetarian diet is based on two pieces of research–one unpublished, both misrepresented– plus an anecdote from a psychiatrist, another from a dietitian who promotes juice cleanses, and the opinion of an ex-vegan book author who is woefully uninformed about nutrition.
None of this has me feeling too worried about vegetarian diets and risk for depression.
In fact, research offers some reassurance about meatless diets and mental health. For example, a small cross-sectional study of Seventh-day Adventists found that a vegetarian diet was associated with better mood.(2) The same researchers found that vegans also experienced mental health benefits compared to omnivores.(3) And in a small, short-term pilot study, they found that several mood scores improved when omnivores stopped eating meat.(4) Vegetarian diets have also been linked to better mood among women in Iran and among new moms in Austria.(5,6)
Finally, vegan diets were associated with less stress and better mental health in a workplace intervention study conducted by PCRM. (7) In this case, the subjects following a vegan diet also received both in-person and online support and instruction. So it’s not possible to know whether improvements in mental health were due to the diet or to the social support. But there is good reason to assume that the switch to a healthy plant-based diet had at least something to do with their improved mood.
One theory is that lower intakes of arachidonic acid, a fatty acid that is abundant in foods from factory farmed animals, offer protection against depression. Arachidonic acid promotes inflammation and inflammation has been linked to a number of chronic illnesses including depression.(8,9)
A higher intake of fruits and vegetables is associated with lower levels of inflammation and possibly with improved mood.(10) This might explain in part why other plant-based diets like Mediterranean diets have also been linked to lower risk for depression.(11) I suspect that soy consumption might also be part of the explanation for lower rates of depression among some groups of vegans and vegetarians.(12)
Overall, we don’t have tons of data on mental health of vegetarians and vegans, but what we know seems reassuring. A diet packed with whole plant foods can reduce inflammation which appears to be good for mental health. Individual plant foods may also offer some protection.
Of course, there are potential shortfalls in vegan diets that could raise risk for depression. Deficiencies of iron, vitamin B12 and vitamin D and of the long chain omega-3 fats DHA and EPA in particular can all affect mood and mental health. None of these deficiencies are unique to vegan diets, though, and all are easily prevented through appropriate supplementation and food choices.
In short, going vegetarian or vegan is not likely to make existing depression or anxiety worse or cause depression in someone who doesn’t currently have it. If anything, it may actually make you feel better. And even if it doesn’t, at the very least your vegan diet is a safe and healthy choice that reflects your values of compassion. That’s something to feel good about.
Vegetarian diet and mental disorders: results from a representative community survey. Michalak J, Zhang XC, Jacobi F. Int J Behav Nutr Phys Act 2012;9:67.
Vegetarian diets are associated with healthy mood states: a cross-sectional study in seventh day adventist adults. Beezhold BL, Johnston CS, Daigle DR. Nutr J 2010;9:26.
Vegans report less stress and anxiety than omnivores. Beezhold B, Radnitz C, Rinne A, DiMatteo J. Nutr Neurosci 2015;18:289-96.
Restriction of meat, fish, and poultry in omnivores improves mood: a pilot randomized controlled trial. Beezhold BL, Johnston CS. Nutr J 2012;11:9.
Empirically derived dietary patterns in relation to psychological disorders. Hosseinzadeh M, Vafa M, Esmaillzadeh A, et al. Public Health Nutr 2015:1-14.
Nutrition health issues in self-reported postpartum depression. Hogg-Kollars S, Mortimore D, Snow S. Gastroenterol Hepatol Bed Bench 2011;4:120-36.
A multicenter randomized controlled trial of a nutrition intervention program in a multiethnic adult population in the corporate setting reduces depression and anxiety and improves quality of life: the GEICO study. Agarwal U, Mishra S, Xu J, Levin S, Gonzales J, Barnard ND. Am J Health Promot 2015;29:245-54.
So depression is an inflammatory disease, but where does the inflammation come from? Berk M, Williams LJ, Jacka FN, et al. BMC Med 2013;11:200.
Dietary inflammatory index, cardiometabolic conditions and depression in the Seguimiento Universidad de Navarra cohort study. Sanchez-Villegas A, Ruiz-Canela M, de la Fuente-Arrillaga C, et al. Br J Nutr 2015;114:1471-9.
The association between fruit and vegetable consumption and mental health disorders: evidence from five waves of a national survey of Canadians. McMartin SE, Jacka FN, Colman I. Prev Med 2013;56:225-30.
Mediterranean dietary pattern and depression: the PREDIMED randomized trial. Sanchez-Villegas A, Martinez-Gonzalez MA, Estruch R, et al. BMC Med 2013;11:208.
Effects of antidepressants and soybean association in depressive menopausal women. Estrella RE, Landa AI, Lafuente JV, Gargiulo PA. Acta Pol Pharm 2014;71:323-7.