Gut microbes are good for mood

Turns out that our societal penchant for fermented foods (think camembert, creamy Greek yoghurt and beer) might not be a bad thing. In fact, if recent research is anything to go by, it’s looking like a diet of the creamy and odourous might be the key to mental health.

Over the past few year, research has begun to accumulate which links mental health and the activity of the human gut’s microbiome. The microbiome, which is defined as the organisms which inhabit our stomach, small and large intestines, is populated by little micro-organisms which are ten times more in number than our own body’s cells.

Until recently, though, the connection was foggy. But now, thanks to the work of a team from Harvard Medical School and Massachusetts General Hospital, the influence seems to be clearer: good gut bacteria, and foods which promote their health, promote our mental health.

The research, published in the Journal of Physiological Anthropology, and lef by Dr Eva M. Selhub, examined the curious influence of fermented food and beverages on mental wellbeing.

They argued that fermented food partly explains the link between traditional dietary practices and positive mental health, given the fact that fermentation has long been practiced as a way to increase the nutritional value (and tastiness) of many foods.

Although they are not sure of exactly how the fermented foods promote mental health (whether it be due direct gut-to-brain communication, or indirect beneficial bodily changes associated with eating such foods, such as anti-inflammatory activity), they do have some ideas.

One is that fermented foods have been shown in prior research to have an effect on lipopolysaccharide (LPS), a toxin is implicated in depression.

Another proposes that an overall positive influence on our health from fermented foods (a balanced diet with plenty of microbe-friendly fermented goodies) could lead to improved neurotransmitter production in the brain (and consequently better mental health).

Interestingly, lactobacillus microbes (those little lovelies found in ‘Probiotic live cultured yogurt), reduce anxiety and depression, according to a study conducted on animals. In fact, the creatures experienced a neurotransmitter alteration that is similar to that experienced by people taking antidepressants.

Further, animals given Bifidobacteria supplements (which are also found in yogurt) were more able to maintain adequate levels of the brain-derived neurotrophic factor (BDNF), levels of which are known to be low in depression, the paper revealed.

The implications? When healthy adults were treated to daily doses of Lactobacillus and Bifidobacterium (num?), they experienced reductions in depression, anger, and anxiety.

The authors conclude that “Modern research is highlighting the potential value of ancestral dietary practices on mental health, and on resiliency against depression in particular. At the same time, there has been tremendous progress toward better understanding of the role played by the low-grade inflammation and the intestinal microbiome in human health and mental wellbeing.”

But beware: Not all the fermented and funky are good for you. Selhub’s team warn that not all fermented foods can be tarred with the same happy brush (some pickled vegetables can grow fungi that increase the production of N-nitroso compounds, which are suspected to be carcinogenic).