We recently published Parts 1 & 2 of a three-part series for our new wellbeing research programme. Here in Part 3, Researcher Network member, Laura Grimes, continues her review of the literature on mental health and veganism and considers how a variety of different lifestyle factors contribute to positive mental wellbeing. However, she asks, where does a vegan diet fit into this?
In the final instalment of this mental health and veganism series, I continue the discussion into what the research says about the link between the two. In parts one and two, I highlighted how the research presents a mixed picture with some studies suggesting that veganism and other branches of vegetarianism can lead to positive mental health outcomes, whilst others reported negative outcomes. Here we look at the other personality or societal traits which vegans may have which also explain these differences.
It would be highly reductionist to state that a dietary choice alone can lead to an improvement or decline in mental health outcomes. Therefore, when we look at the bigger picture we can see that often differences do exist between vegetarians' and omnivores’ values and worldviews, with vegetarians being reported to be more politically liberal and empathic (Ruby, 2012). For example, one study concluded that young women who are passionate about the ethical beliefs which motivated their decision to become vegan often benefit from a vegan diet and a reported protective effect which it can have in preventing disordered eating in the future (Santivañez-Romani et al., 2018). Although specifically what this protective effect is, is still to be determined. Perhaps a focus on a healthy and balanced diet that meets all of the primary macro and micronutrients creates a positive spotlight on how to live well and support the human body?
Contrary to this in terms of social relationships, some vegetarians do report that this lifestyle can strain social and professional relationships (Hirschler, 2011) with a negative bias towards a vegetarian diet (Cole & Morgan, 2011) being one possible source of the poorer mental health which some studies have reported compared to omnivores. Vegetarians and vegans alike can often receive negative bias as a result of their life choices with passive comments in relation to “I don’t know how I could live without meat,” and “what do you eat instead then…?” Does this sound familiar to any fellow vegetarians and/or vegan readers? Certain social situations when sitting at a table full of passionate omnivores can lead to the single vegan or vegetarian at the table being subjected to a few uninvited negative opinions as to what is, a personal lifestyle choice. If this occurred frequently enough - a complex psychology could be considered to surround vegetarian and vegan lifestyles which impacts negatively upon mental health outcomes.
Interventional studies are generally demonstrating that vegetarian and vegan diets produce improvements in mental health and social functioning and which can be attributed to a variety of reasons. One study reports that a vegan diet produces greater reductions in reported pain compared to a placebo supplement (Bunner et al. 2014) whilst improvements in neuropathic pain as measured by three validated tools was also observed compared to a control group (Bunner et al. 2015). Understandably in patients presenting with chronic or neuropathic pain – dramatic improvements in such will contribute to improved mental health outcomes as a result.
Overall many interventional studies conclude a dramatic improvement in anxiety and depression, however, even more specifically, reports of improvements in workplace productivity were also reported as a result with one study finding that a vegan diet improves all three variables in participants with a body mass index >25kg/m2 and/or with a previous or current diagnosis of type two diabetes. Whether this outcome is due to the weight loss experienced as a result of following a vegan diet, which would inevitably improve the overall physical health of participants as well as their quality of life, this is a finding which can be applied to clinical settings and workplaces to holistically improve the quality of life of patients and employees alike. By consequently reducing risk factors such as obesity, high blood pressure and type two diabetes it would be considered possible to holistically improve the physical and mental health of the population, in line with an extensive pre-existing evidence base which suggests that lifestyle programmes designed to improve physical health also result in improved mental health (Happell et al. 2012, Nash, 2011).
Conversely, the findings from the observational studies included in this review are more mixed, with many reporting deteriorating mental health with some specific relationships found between certain facets of mental illness. It appears that whilst the interventional studies demonstrate a positive impact upon mental health, observational studies do not and this is possibly down to confounding factors. The degree of confounding depends on the prevalence of the putative confounding factor, the level of its association with the disease, and the level of its association with the exposure (Psaty et al. 1999), therefore factors such as socio-economic status (which few of the observational studies meeting the inclusion criteria monitored for) and pre-existing mental illness would have significantly impacted the outcomes.
Optimistically, it seems that vegetarian and vegan diets can really have a positive impact on mental health and wellbeing as well as other aspects of day to day functioning, but the method used to assess this can produce a mixed picture when assessing the literature.
The views expressed by our Research News contributors are not necessarily the views of The Vegan Society.
