Riboflavin: the vitamin that helps good bacteria work better

Staff editor

28.05.2025

Vitamins like riboflavin may support health not only through direct effects, but also by boosting beneficial microbial functions.

What is already known

Gut health depends on a delicate balance of the microorganisms living inside us. Among them, Faecalibacterium prausnitzii stands out for its ability to produce short-chain fatty acids (SCFAs), such as butyrate, which play a key role in reducing inflammation, supporting gut integrity, and feeding the cells of the colon. Scientists have long been interested in ways to increase the presence and activity of such beneficial microbes—through probiotics, diet, or supplements.

What this research adds

A new clinical study investigated how high doses of riboflavin (vitamin B2) affect the gut microbiome of healthy individuals. Researchers found that riboflavin supplementation can enhance the functional activity of the gut microbiota without altering its composition. Notably, it increased butyrate production—a key metabolite for gut health—and improved the complexity and stability of microbial networks.

Conclusions

These findings suggest for the first time that vitamins like riboflavin may support health not only through direct effects, but also by boosting beneficial microbial functions.

The human gut microbiota plays a central role in health, particularly thanks to beneficial bacteria like Faecalibacterium prausnitzii, a key producer of butyrate—a compound known for its anti-inflammatory and gut-protective effects. A decline in these bacteria is often observed in conditions such as inflammatory bowel disease and obesity. Recent studies suggest that vitamins with antioxidant properties, like riboflavin (vitamin B2), may support these microbes and enhance their metabolic activity.

A novel study published in Antioxidants & Redox Signaling Journal and conducted with the support of DSM-Firmenich, found that riboflavin supplementation led to increased butyrate production and more stable microbial networks.

Scientists led by Dr. Hermie J. M. Harmsen conducted a randomized, placebo-controlled trial at the University Medical Center Groningen, including 105 individuals that were randomized in three groups, with the primary objective to determine the effect of 2 weeks oral riboflavin supplementation (50 and 100 mg/d) on the number of F. prausnitzii in feces in comparison with placebo.

Riboflavin supplementation increased fecal SCFAs concentration

Riboflavin supplementation led to an increase in fecal concentrations of SCFAs, particularly butyrate and acetate. A significant rise in butyrate was observed in the 100 mg/day group, while acetate levels increased in the 50 mg/day group. When both intervention groups were analyzed together, the combined data also revealed a statistically significant boost in butyrate levels after riboflavin supplementation. Although the relative abundance of Faecalibacterium prausnitzii remained unchanged, butyrate concentrations positively correlated with its presence, as well as with other SCFA-producing bacteria. These results suggest that riboflavin may enhance microbial metabolic activity and cross-feeding interactions in the gut, increasing beneficial SCFA production without altering microbial composition.

Riboflavin intervention enhanced bacterial networks

To better understand the observed increase in butyrate, researchers analyzed the structure of microbial interactions within the gut. They found that riboflavin supplementation, particularly in the combined group and the 100 mg/day group, significantly enhanced the complexity and stability of bacterial networks. The different bacterial species started interacting more with each other, forming a stronger, more interconnected community. Notably, the central species within these networks shifted after riboflavin intake—from Anaerostipes to Roseburia, both known butyrate producers—which began forming new connections with acetate-producing bacteria. These findings suggest that riboflavin may promote more efficient cross-feeding and cooperative behavior among gut microbes, contributing to improved metabolic output without altering microbiota composition.

Metabolic effects of riboflavin

In a subgroup of participants, researchers performed an oral glucose tolerance test (oGTT) to investigate whether riboflavin would affect metabolic markers. While results did not reach statistical significance, they observed a trend toward increased insulin and GLP-1 levels in individuals receiving 100 mg/day of riboflavin. GLP-1 is a hormone involved in appetite regulation and blood sugar control. Although preliminary, these findings suggest that riboflavin may influence not just gut bacteria, but also the host’s metabolism through changes in microbial activity and SCFA production. Further research with longer intervention periods or larger groups may help clarify these effects. In conclusion, the RIBOGUT study demonstrated that while two weeks of riboflavin supplementation did not alter the composition or abundance of key gut bacteria such as F. prausnitzii, it significantly enhanced the functional activity of the microbiota. Riboflavin was well absorbed and well tolerated, with no adverse effects reported. All together these findings suggest that riboflavin may serve as a safe and effective strategy to support gut microbial function and metabolic health, even in individuals with an already stable microbiota.

Source

Antioxidants & Redox Signaling Journal