The sulfur microbial diet and increased risk of obesity: Findings from a population-based prospective cohort study

Gut-produced hydrogen sulfide (H₂S) has been associated with increased gut permeability and inflammation, which may be related to higher obesity risk. We investigated the association of sulfur microbial diet, a dietary index associated with 43 sulfur-metabolizing bacteria, with the incident obesity and whether the relationship was modified by the genetic predisposition to obesity.

We included 27,429 participants with available body mass index (BMI) data from the UK Biobank. The sulfur microbial diet score was assessed using the 24-h dietary assessment method. Obesity and abdominal obesity were defined according to the World Health Organization criteria. Body fat percentage was assessed using a body composition analyzer. The genetic risk score (GRS) was calculated by 940 BMI-related variants.

We documented 1472 and 2893 cases of obesity and abdominal obesity during a mean follow-up of 8.1 years. After multivariable adjustment, the sulfur microbial diet score was positively associated with obesity (HR_Q4vsQ1 = 1.63; 95% CI = 1.40-1.89, P-trend = 0.001) and abdominal obesity risk (HR_Q4vsQ1 = 1.17; 95% CI = 1.05-1.30, P-trend = 0.002). We also observed that increased sulfur microbial diet score was positively related to several adiposity indicators, including a 5% increase in BMI, WC, and body fat percentage. Moreover, the sulfur microbial diet had no significant interactions with genetic risk on obesity incidence.

Our results emphasized the significance of avoiding the sulfur microbial diet for obesity prevention across all levels of genetic risk.