Interaction of plant-based diets and gut microbiota

A 2022 Alpro Foundation fully referenced scientific report

The importance of the gut microbiota in human health has become increasingly evident, although the understanding of what constitutes “healthy microbiota” remains unclear. Numerous studies have shown that diet is one of the most important lifestyle factors that influences the composition of human gut microbiota.

This in-depth and fully referenced scientific update, by Dr Véronique Braesco, Dr Petra Louis and Dr Ian Rowland, reviews the latest available evidence regarding the effects of plant-based diets on the composition and metabolism of gut microbiota.

Key learnings from the report:

• The gut microbiota can influence and modulate the health of the individual, and its composition and metabolism are affected by dietary patterns.

• Comparisons between individuals or populations consuming plant-based and Western diets have shown differences in composition and/or metabolic activity of gut microbiota.

• The indication is that plant-based diets may be more beneficial for the gut microbiota.

• The increased fibre intake associated with many plant-based diets is believed to play a key role in the changes seen in microbiota composition and metabolism

• Higher intakes of dietary fibre increases short-chain fatty acid (SCFA)-producing bacteria. And it is well established that SCFAs are associated with various benefits including:

  • Strengthening the intestinal epithelial layer, supporting the immune system against pathogenic bacteria

  • May improving energy metabolism

  • Increasing colonic motility and decrease visceral pain

  • Antiproliferative properties in cancer cells with a potentially favourable role in colon cancer

• Plant-based diets are also associated with high levels of polyphenols, which have been shown to beneficially modify the gut microbiota composition

• Plant-based diets are associated with reduced formation of potentially deleterious bacterial metabolites such as secondary bile acids, indole and p-cresol, and the pro-atherogenic compound trimethylamine oxide (TMAO)

Although the precise make-up of the optimal diet for gut microbiota has yet to be identified, a balanced diet composed of a variety of plant foods appears to have the greatest potential to positively modify gut microbiota composition and metabolism through increased intake of fibre and polyphenols and reduced intake of animal products.

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