Vegetarians generally enjoy a lower risk of cardiovascular disease, diabetes, obesity and some cancers. However, effect on mental health , as far as we know , seems to suggest a different story. Among Australian women, depressive symptoms were more reported among vegetarians (Baines et al 2007). Another study , again from Australia, showed that lower end meat consumption was associated with doubling the risk of depression and anxiety (Jacka et al 2012). Similar findings were reported from Norway , Germany and Turkey ( Larssson et al 2001, Michalak et al 2012 etc). It is possible that vegetarian diet may have less Iron, Zinc, Vit B12 and Omega 3 compared to non vegetarian diet and this may explain the observed associations.
JR Hibbeln and colleagues studied whether self-identification of a vegetarian diet was associated with increased risk of depressive symptoms among adult men during the pregnancy of their partners.
Self-report data from 9668 adult male partners of pregnant women in the Avon Longitudinal Study of Parents and Children (ALSPAC) is analysed to see whether diet is associated with depressive symptoms. ALSPAC is an ongoing population based cohort study, based in Avon in the UK, investigating environmental and other influences on the health and development of children. Men completed the Edinburgh Postnatal Depression Scale (EPDS) as part of assessments of the pregnant women who were recruited to this cohort. Comprehensive background data for these men were also collected.
Multivariate analysis suggest that factors like housing tenure, number of children in the household, religion, family history of depression,alcohol consumption, marital status and employment status were independently associated with depressive symptoms. Vegetarians show more depressive symptoms after adjusting for all the above factors. When EPDS scores were converted to binary variable the association still held positive. Elevated odds ratio for an EPDS score greater than 10 and vegetarianism was 1.71 (95% CI: 1.17, 2.49; p = 0.005).
This is the first large epidemiological study to show a relationship between vegetarian diet and significant depressive symptoms among adult men. The increased risk of depressive symptoms is seen when symptoms are evaluated either as a continuous scale or while using a cut-off of greater than 10 on the EPDS. This association persists even after adjusting for all other known vulnerability factors.
1. Vegetarians have lower intake of omega 3, Vit B12 and folate . They may be taking more omega 6 (from nuts). Veg diet may be associated with increased intake of phytoestrogens, and possibly more of metabolites of pesticides.
2. It is possible that vegetarians were making a dietary choice because they had to reduce weight / and or may have medical conditions that prompted them to do so. Such medical conditions may be associated with depression.
4. Vegetarianism MAY BE an expression / marker of psychiatric/ personality problems in certain populations where vegetarianism is not the norm. Dissatisfaction with one’s body is a frequent theme among adolescents who adopt vegetarianism in a meat preferring eating culture.
No serum levels of nutrients collected in this study.
Reverse causality cannot be completely ruled out.
Vegetarian status was self identified rather than based on food frequency questionnaires. It is known that many self identified vegetarians are found to consume non vegetarian food when detailed dietary habits are collected.
High meat consumption is also shown to be associated with depressive symptoms. Such unhealthy dietary patterns often go hand in hand with physical inactivity, smoking and alcohol consumption. It needs to be seen whether the observed association between vegetarian diet and depressive symptoms holds true in populations where vegetarianism is the main stream dietary practice.
Summary of teh article:
Vegetarian diets and depressive symptoms among men. Hibbeln JR, Northstone K, Evans J, Golding J. J Affect Disord. 2017 Jul 28;225:13-17. doi: 10.1016/j.jad.2017.07.051. [Epub ahead of print] PMID: 28777971