Dietary index for gut microbiota and DXA-derived visceral adiposity: a cross-sectional study

Visceral adipose tissue (VAT) is a critical cardiometabolic risk factor, yet the association between the dietary index for gut microbiota (DI-GM) and VAT mass remains unclear.

This cross-sectional study included 9,805 adults aged 20-59 years from the National Health and Nutrition Examination Survey (NHANES) 2011-2018 (age range based on DXA data availability). DI-GM scores were calculated based on 24-hour dietary recall data using 13 dietary components. VAT mass was directly measured using dual-energy X-ray absorptiometry (DXA). Multivariable weighted linear regression models, restricted cubic spline (RCS) analysis, and subgroup analyses were employed to assess the association between DI-GM and VAT mass.

After comprehensive adjustment for potential confounders, DI-GM score was significantly inversely associated with VAT mass (β = -8.8, 95% CI: -12.0 to -5.5, P < 0.001). Participants in the highest DI-GM quartile (≥ 6 points) had 38.1 g lower VAT mass compared to those in the lowest quartile (0-3 points) (P < 0.001). RCS analysis revealed a linear dose-response relationship with no evidence of nonlinearity (P for nonlinearity = 0.632). Subgroup analyses revealed that this inverse association was more pronounced among individuals aged 40-59 years (β = -12.7, 95% CI: -18.3 to -7.1) and females (β = -12.0, 95% CI: -16.2 to -7.9), with significant interactions detected (P for interaction = 0.001 and 0.032, respectively).

Higher DI-GM scores were significantly associated with lower VAT mass in United States adults. Prospective studies are needed to confirm these findings and establish causal relationships.