(P40-09-26) Ultra-Processed Foods Link to Gut Microbial Sulfite Metabolism Genes

Objectives: Ultra-processed foods (UPF) contain sulfur additives, such as sulfites and caramel coloring, which may influence gut microbial sulfur cycling. Key sulfite metabolism genes include anaerobic sulfite reductase (asr) and dissimilatory sulfite reductase (dsr), but links to ultra-processed diets are underexplored. We tested whether UPF intake, particularly from ultra-processed beverages (e.g., sugar-sweetened and alcoholic drinks), correlates with microbial gut sulfite-metabolism gene abundance (asr, dsr, cysJ) and sulfite-reducing taxa.

Methods: We studied 138 adults (45–75 years) recruited from two urban academic medical institutions in Chicago, IL. Participants completed two 24-hour dietary recalls, and stool samples were collected within five days of the first interview and stored at −80°C. Dietary data were classified using the NOVA system by two independent coders (with a third resolving discrepancies) and recategorized into 18 UPF subcategories. UPFs were screened for sulfur additives, including sulfate, sulfite, and caramel coloring, using name-brand and off-brand ingredient lists. Fecal DNA was shotgun sequenced, while sulfite metabolism genes (dsr, asr, cysJ) were identified using hidden Markov model libraries, and abundance was correlated with the percentage of total energy from UPFs (NOVA group 4 kcal/total kcal × 100) using unadjusted Spearman correlations.

Results: Among participants, 13% of consumed foods contained caramel coloring. Asr and dsr genes showed significant positive correlations with percent total kcal from UPFs (N=138; p < 0.02 and p < 0.005, respectively). Sugar-sweetened beverages and alcohol showed the strongest associations with sulfite metabolism gene abundance.

Conclusions: This analysis relied on unadjusted correlations, so findings represent associations, not causation. Ongoing work includes chemical assays to quantify sulfur species in beverages and in vitro experiments to test metabolism of beverage-derived sulfites by representative microbial isolates.

Funding Sources: National Cancer Institute, National Center on Minority Health and Health Disparities