What Sulfites Really Do in Wine: New Research Sheds Light on the Gut Connection

New Study Explores How Wine Sulfites Interact with the Gut Microbiome

Sulfites are a mainstay in winemaking, valued for preserving freshness and stability—but their impact on human health has long been debated. Now, researchers have taken the first close look at how sulfites interact with the gut microbiota under simulated digestive conditions.

Using the SIMGI gastrointestinal model, scientists compared red and synthetic wines with and without added sulfur dioxide (200 mg/L). The findings show that sulfite-treated wines subtly shifted gut microbiota composition, reducing beneficial bacteria such as Bacteroides and Ruminococcus, while increasing populations of Coprococcus and potentially pro-inflammatory Escherichia/Shigella. The degree of impact, however, appeared to depend on each individual’s baseline microbiome resilience.

Interestingly, red wine seemed to soften these effects—likely due to its polyphenols, which may play a protective role. The study also revealed that sulfites enhanced phenolic metabolism, boosting bioavailable compounds like valerolactones in the gut. For example, concentrations of 5-(3′,4′-dihydroxyphenyl)-γ-valerolactone were consistently higher in sulfite-treated red wine compared to untreated samples.

This pioneering research highlights a complex relationship between sulfites, wine compounds, and the gut microbiome—raising fresh questions about their health implications, particularly for sulfite-sensitive individuals.

Journal of Agricultural and Food Chemistry, 2025; 73 (31): 19397 DOI: 10.1021/acs.jafc.5c02710