Traditional Diets and Gut Bacteria: A tale of Two Microbes (Part 2)

To recap where we left off from Part 1 of this article; 

Hunter-gatherer societies have unique gut bacteria—known as the gut microbiota—that are likely protective against obesity and all the negative health consequences that come with being overweight. This is due in part to the large quantity of prebiotics that these traditional societies consume in their diet. What differs between our gut bacteria and theirs, and why might it be such a big deal? 

THE GUT BACTERIA SPECIES: PREVOTELLA & BACTERIOIDES

For the past year, I’ve been researching the gut microbiota variations between Western peoples and seven different hunter-gatherer and traditional societies: the Yonomami people of Venezuela[1], the Sausi and Asoro of Papua New Guinea [2], the Matses and Tunapuco from Peru [3], the Mossi of Burkina Faso4, and the Hadza of Tanzania[5]. All of them differ quite significantly from each other (and from us) in terms of their gut microbiota ecosystem. But one unifying thread that connect these geographically separate, traditional societies from Western ones is that not only do they have much higher diversity in bacterial species, but they have much higher levels of a species called Prevotella, whereas we have more of the species Bacterioides.

HOW TO INCREASE YOUR LEVELS OF PREVOTELLA?

It is thought that Prevotella thrives best when its host consumes high levels of fibrous, prebiotic-containing plant-based foods, whereas Bacteroides can resist and thrive when there’s more animal fats and processed foods being ingested (as is the case in modern diets). When fiber and prebiotics enter the colon, both Prevotella and Bacteroides can ferment these into products called short-chain fatty acids (SCFAs). Where the two microbes differ, however, is that Prevotella makes two to three times more of the SCFA propionate than Bacteroides does. 

HIGHER LEVELS OF PROPIONATE COULD PREVENT WEIGHT GAIN

A recent clinical trial in humans have demonstrated that propionate has potent anti-obesity effects, mainly by tricking the brain into thinking it’s less hungry than it would be ordinarily; results from the study showed that participants who had received propionate supplementation consumed 14% fewer calories overall in their diet compared to participants who received a placebo. Taken over a lifetime, such a 14% reduction could prevent the weight-gain that comes with ageing.

THINGS ARE GETTING WORSE, BUT UNDERSTANDING THE MICROBIOTA CAN HELP

So as this global pandemic of obesity, diabetes, and high blood-pressure continues to worsen, novel therapies targeting the gut microbiota will become crucial. Expanded research and development into human-to-human microbiota transplantation and over-the-counter synbiotics (supplements which contain both prebiotics and live bacteria) have the potential to alleviate this pandemic. This will require the need for super donors who have optimal gut microbiota profiles—traditional, hunter-gatherer societies harboring Prevotella could become invaluable for providing such super donors. For this reason, the scientific community really needs to expedite gut microbiota research before traditional cultures and their dietary habits are completely wiped out by the advance of the modernized world.

- Tyler Feeney- 
M.Sci (c) in Dietetics

References

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