Prevotella is a group of bacteria naturally found in the human mouth, gut, and other mucosal surfaces. In the gut, certain Prevotella species help break down complex carbohydrates and plant fibres, producing short-chain fatty acids (SCFAs) that support gut health and provide energy to intestinal cells (Yang et al., 2022; Waters & Ley, 2019).

The role of Prevotella in human health is complex. Some species are associated with beneficial effects, such as improved blood sugar regulation and reduced inflammation, while others can contribute to infections or chronic inflammation in certain contexts (Iljazovic et al., 2021; Larsen, 2017). The balance of Prevotella species — along with overall gut microbiome diversity — appears to be key in determining whether their impact is helpful or harmful.

✔ What it is: A group of bacteria commonly found in the human mouth, gut, and other mucosal surfaces.

✔ What it does: Breaks down complex carbohydrates and plant fibres into short-chain fatty acids (SCFAs) that nourish gut cells and support colon health (Yang et al., 2022).

✔ Gut health: Helps maintain a healthy gut environment, especially in people with fibre-rich diets.

✔ Metabolic health: Certain species, like Prevotella copri, have been linked to better blood sugar control and improved insulin sensitivity (Yang et al., 2022).

✔ Immune effects: Can modulate immune responses, influencing inflammation and tolerance to gut microbes (Iljazovic et al., 2021).

✔ Dual nature: Some species are beneficial, while others are associated with chronic inflammation or infection in specific conditions (Larsen, 2017).

✔ Where to find it: Naturally present in the gut microbiome and influenced by dietary patterns, particularly high-fibre plant-based diets.

Members of the Prevotella genus can support gut health by breaking down dietary fibres and resistant starches into beneficial short-chain fatty acids (SCFAs) like propionate and acetate. These SCFAs help nourish intestinal cells, strengthen the gut barrier, and create an environment that discourages the growth of harmful bacteria (Yang et al., 2022; Waters & Ley, 2019).

Certain Prevotella species, such as Prevotella copri, are linked to improved metabolic health, including better blood sugar regulation and enhanced insulin sensitivity, particularly in people consuming high-fibre diets (Yang et al., 2022). By contributing to a balanced gut microbiome, Prevotella may also help regulate immune responses and reduce low-grade inflammation, which is important for preventing chronic diseases (Iljazovic et al., 2021).

When Prevotella levels are too high or dominated by harmful strains, or when beneficial species are too low, it can disrupt gut balance and contribute to health issues. Possible symptoms include:

✔ Digestive discomfort: bloating, gas, diarrhoea, or abdominal cramps linked to gut inflammation or imbalance (Larsen, 2017).

✔ Increased inflammation: higher levels of certain Prevotella strains have been associated with systemic inflammation and related symptoms such as joint pain or fatigue (Iljazovic et al., 2021).

✔ Oral health issues: Overgrowth in the mouth may contribute to gum disease and bad breath (Larsen, 2017).

✔ Worsening of chronic conditions: In some people, excess Prevotella may be linked to autoimmune disorders like rheumatoid arthritis (Iljazovic et al., 2021).

✔ Metabolic disturbances: imbalances may affect blood sugar control, particularly in people on low-fibre diets (Yang et al., 2022).

Balanced populations of beneficial Prevotella species — especially Prevotella copri — may help protect against certain metabolic and inflammatory diseases. By breaking down dietary fibres into short-chain fatty acids (SCFAs) like propionate, these bacteria can improve blood sugar regulation, enhance insulin sensitivity, and reduce the risk of type 2 diabetes in individuals consuming high-fibre diets (Yang et al., 2022).

Some studies suggest that Prevotella can also promote a healthier immune system by modulating inflammatory pathways and supporting gut barrier integrity, which may lower the risk of chronic low-grade inflammation linked to cardiovascular disease and other conditions (Iljazovic et al., 2021; Larsen, 2017). However, this protective effect depends on maintaining a balanced gut microbiome, as overgrowth or the presence of more inflammatory Prevotella strains may have the opposite effect.

✔ Eat a fibre-rich diet: Whole grains, legumes, fruits, and vegetables promote the growth of beneficial Prevotella species that thrive on plant-based fibres (Yang et al., 2022).

✔ Increase resistant starch intake: Foods like cooked-and-cooled potatoes, green bananas, and lentils provide fuel for Prevotella and help produce beneficial short-chain fatty acids.

✔ Follow a balanced plant-forward eating pattern: Diets rich in diverse plant foods, such as the Mediterranean or traditional high-fibre diets, support a healthier Prevotella balance (Larsen, 2017).

✔ Limit processed and high-fat foods: Diets high in saturated fats and low in fibre can reduce Prevotella diversity and allow harmful strains to dominate.

✔ Avoid unnecessary antibiotics: Overuse can disrupt gut microbiome diversity, including beneficial Prevotella species.

✔ Consider prebiotics: Specific prebiotic fibres, like inulin and fructooligosaccharides, may encourage the growth of beneficial Prevotella strains.