Dr's Casebook: ​Fermented foods may be good for gut and brain

Dr Keith Souter writes: I am always exploring papers about the microbiome and the effects that it has on health. Recent research suggests that fermented foods and drinks may have beneficial effects on both the gut and the brain by virtue of the effect of the compounds contained within them.

It is well known that some foods can positively boost one’s mental health, while other foods, especially highly processed ones can have a negative impact. Fermented foods are a source of tryptophan, an amino acid key to the production of serotonin, a neurotransmitter or messenger in the brain which influences several aspects of brain function, including mood. It has been thought that they may also contain other brain neurotransmitters in a raw form.

Kombucha is also known as the tea mushroom or the tea fungus. As a bread-maker I have always been fascinated by the process of fermentation and for a long time I kept a kombucha culture to produce my own fermented drink. It is a fun thing to do.

Researchers at the University of Cork in Ireland are studying fermented foods by comparing sequencing data from over 200 foods from all over the world. They are looking for a whole range of these neurotransmitters thought to have a positive impact on brain and mental health.

So far the results have been very impressive. They have found that out of these 200 fermented foods, almost all of them showed the ability to exert some sort of potential to improve gut and brain health.

Although sugar-based products may have a bad name, in the case of sugar-based fermented foods and drinks the raw sugar contained in them is converted into a number of metabolites that can be beneficial. Effectively, the sugar gets used by the microbes that are present in these ‘live’ foods and drinks into these beneficial messengers.

It is all very exciting and it adds significantly to the growing body of research on fermented drinks and gives a reason to consider including fermented foods in the diet as a natural way of supporting one’s general well-being.