May sulfites in wine affect gut microbiota? An in vitro study of their digestion and interplay with wine polyphenols

Sulfites are widely used in the wine industry, but their effects on human health remain debated. A study examined the interaction between wine sulfites and gut microbiota under simulated gastrointestinal conditions. Using the simgi model, red and synthetic wines—with and without SO2 (200 mg/L)—underwent gastrointestinal digestion and colonic fermentation with faecal microbiota from three healthy donors. SO2-treated wines slightly altered gut microbiota composition, reducing beneficial bacteria like Bacteroides and Ruminococcus while increasing Coprococcus and pro-inflammatory Escherichia/Shigella, although the overall microbiome of each individual seemed to influence its resilience to SO2. These effects were partly mitigated in red wine, suggesting a protective role of wine polyphenols. Additionally, SO2 treatment in red wines enhanced phenolic metabolism in the gut, increasing low-molecular-weight phenolic compounds, such as valerolactones, which are bioavailable in the small intestine and colon. This pioneering study reveals a complex interplay between sulfites, wine components, and gut microbiota, with potential health implications, especially for sulfite-sensitive individuals.
Source: Relaño de la Guía E, Cueva C, Molinero N, Ruano A, Motilva MJ, Bartolomé B, & Moreno-Arribas MV. (2025) May sulfites in wine affect gut microbiota? An in vitro study of their digestion and interplay with wine polyphenols. Journal of Agriculture and Food Chemistry, 73(31):19397-19409. .