Su1994 – The Common Food Additives Sodium Sulfite and Polysorbate 80 Have a Profound Inhibatory Effect on the Commensal, Anti-Inflammatory Bacterium Faecalibacterium Prausnitzii. the Enigma Study

a disturbed microbiome.Methods: To test this, we have performed dietary and microbiome studies in 20 middle-aged (50-65y) healthy male and female rural high-risk South Africans (RA) and compared them to 20 low risk age and sex matched African Americans (AA).To further test the sensitivity of the differences to dietary change, we then switched their diets in-house under strictly controlled conditions for 2 weeks as previously reported (Nature Comm 2015).Distal esophageal and gastric antral microbiota were sampled and immunohistological (IHC) measurements made for proliferation biomarkers (Ki67) of cancer risk from endoscopic biopsies collected in liquid nitrogen and formalin 2 weeks before and then again at the end of the dietary switch, await transport and analysis in Pittsburgh.Results: Dietary analysis confirmed lower intakes of protein and water-soluble vitamins and higher proliferation rates in RA.Microbiota composition in both the esophagus and stomach were significantly different between the 2 populations (Fig) .Diet switch had no significant overall effect in on the antral microbiota and mucosal cancer biomarkers, but trend towards significance in the esophagus.At a species level, there were more Helicobacter pylori (HP) in the NA relative to AA in the antrum, with a decrease in HP and increase in Pasturellaceae and Alloprevotella following diet switch.In addition, there were more Streptococcus in the AA and more Haemophilus in the NA relative to AA in the esophagus Conclusions: Our results showed that significant differences in microbiota composition accompany the differences in dietary intake and cancer risk biomarkers in the microclimate of the distal esophagus, which is the site of development of squamous cell carcinomas.Our results indicate that 2 weeks is insufficient time to significantly change the milieu but do not exclude the possibility of specific microbes e.g.Haemophilus, driving cancer risk in a nutritionally depleted esophageal mucosa, and HP in the stomach Illustration of the color-coded pattern differences in major microbial subroups measured by16S rRNA gene sequencing Mucosal Proliferation Cancer Biomarkers (Ki67+ cells %) Rural Africans African Americans Esophagus 26.3(7.2)*8.1(4.2)*Gastric Antrum 51.1(4.4)*16.8(2.1)** 95% confidence intervals Su1992