The importance of the gut microbiota in human health has become increasingly evident. It has been clearly demonstrated that the composition and the functionality of the gut microbiota affect many aspects of health, even though the understanding of what is a “healthy microbiota” is still unclear. Numerous studies have shown that diet is one of the most important lifestyle factors that affects the composition of the human gut microbiota.
This scientific update written by Dr Véronique Braesco, Plant-based diet and gut microbiota – March 2022aims at reviewing the available evidence regarding the effects of plant-based diets on the composition and metabolism of gut microbiota.
- 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.
- There are indications that plant-based diets may be more beneficial for the gut microbiota.
- There is some consensus that the increased fibre intake associated with many plant-based diets is an important factor in the changes seen in microbiota composition and metabolism
- Higher intake of dietary fibre is leading to increases of short-chain fatty acid (SCFA)-producing bacteria in many studies. SCFAs have several identified benefits:
- Strengthen the intestinal epithelial layer, helping the immune system against pathogenic bacteria.
- May improve energy metabolism and leanness.
- Increase colonic motility and decrease visceral pain.
- Have 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. They are extensively metabolized by the microbiota into potentially beneficial derivatives.
- Plant-based diets are associated with reduced formation of potentially deleterious bacterial metabolites such as secondary bile acids, indole and p-cresol, and the proatherogenic compound trimethylamine oxide (TMAO)
- When it comes to which diet is best for the gut microbiota, this scientific update shows that we are still far from being able to provide definitive advice. However, balanced diets focused on a variety of plant-based foods have the potential to positively modify gut microbiota composition and metabolism through increased intake of fibre and polyphenols and reduced intake of animal products.