Gut-microbiota-targeted diets modulate human immune status
Gut-microbiota-targeted diets modulate human immune status (2021) Wastyk et al
Context
I’m always on the lookout for the best sources of nutrition for my body and my gut microbiota. When reading Vincent Pedre’s new book (see below) on eating for a healthy microbiome I came across this paper from scientists at Stamford University, America.
The scientists conducted a small experiment comparing two types of diet. This is an important point to understand. This was not a review of past studies comparing associations between diet and health, in which different diets may or may not have been the cause of a health outcome.
The authors describe how a diet high in fermented food resulted in increased microbiota diversity and healthier immune response compared to a diet higher in plant fibre. This is a little different from the popular message that a diet high in plant fibres is the primary driver of a healthy gut.
Results of the study
The authors investigated the effects of two types of diet, one high plant fibre and the other fermented foods on human gut microbiota and subsequent human immune system benefit.
The high plant fibre diet did not increase microbiota diversity or the production of anti-inflammatory proteins in the human host.
The high fermented food diet did increase the diversity of the gut microbiota and reduced the levels of compounds associated with chronic inflammation.
“These results suggest that fermented foods may be powerful modulators of the human microbiome-immune system axis and may provide an avenue to combat [chronic disease]”
Why are the results of the study interesting?
This paper brings together a couple of themes that I’ve seen in the popular and academic literature. In the former, healthy human gut microbiota diversity is routinely described as linked to high plant fibre diets. Advocates of this approach often refer to “eating the rainbow” as a way to encourage consuming a range of colourful fruits and vegetables.
The academic literature contains a range of views on healthy human gut microbiota diversity but one theme strikes me as intriguing. Our modern lifestyle which includes a high degree of indoor living, processed foods, and overall “cleanliness” has stopped us from encountering a range of naturally occurring microorganisms. This lifestyle may be contributing to decreased gut microbiota diversity and ensuing incidence of chronic diseases. This paper shows that eating fermented foods with their populations of live microorganisms appears to be better at creating healthy gut microbiota than eating lots of fruits and vegetables.
The authors state that “These results suggest that fermented foods may be powerful modulators of the human microbiome-immune system axis and may provide an avenue to combat NCCDs.” A NCCD is a non-communicable chronic disease such as heart disease, type 2 diabetes, etc.
How do the results of the study help me to understand health and longevity?
This study has confirmed that fermented foods should play a central role in my gut-friendly diet. This does not preclude, for me, eating a range of high fiber berries and vegetables, and I will continue with both. As always, what works for me, may not for someone else. It is important always to remember how different we are from each other.
Individual variation aside, there are still foundational principles that can be used by each of us. This paper shows that fermented foods are worth each of us considering as a regular component of what we consume.
I’d love to see this type of investigation repeated with more men and different ethnicities to test the applicability of fermented and plant-derived foods in the wider population.
Study outline
A randomized dietary intervention study of 39 (mainly white women) participants over a ten week period.
Reference
Wastyk, H.C., et al (2021) Gut-microbiota-targeted diets modulate human immune status. Cell, 4137-4153. DOI:https://doi.org/10.1016/j.cell.2021.06.019
Additional reading
The Gutsmart Protocol by Vincent Pedre, M.D., Published: 2023, Dallas, TX, BenBella Books