Inflammatory dietary potential and gut microbiota in older adults with overweight or obesity and metabolic syndrome.

Anti-inflammatory dietary potential was significantly associated with increased alpha diversity indices at baseline and after 1 year.

• Lower E-DII score (anti-inflammatory) was associated with increased Chao1, Inverse Simpson, and Shannon alpha diversity indices (all P < 0.05)
• Associations were observed both as continuous and categorical E-DII score measures
• Results remained significant when evaluating changes in E-DII over time with changes in alpha diversity indices
• Study included 648 participants with mean age 65 ± 5 years, 47% women, all with overweight/obesity and metabolic syndrome

Anti-inflammatory dietary potential was associated with distinct beta diversity profiles at both baseline and 1-year follow-up.

• At baseline: R² = 0.004, PERMANOVA P = 0.047
• After 1 year: R² = 0.006, PERMANOVA P = 0.003
• Beta diversity profiles were assessed using 16S rRNA sequencing
• The association strengthened over the 1-year period as indicated by increased R² and lower P value

Anti-inflammatory E-DII score was associated with 24 microbial genera, 4 faecal metabolites, and 1 metabolomic network.

• All associations met the false discovery rate threshold of FDR < 0.05
• Gut microbiota was characterized using 16S rRNA sequencing
• 518 identified faecal metabolites were analysed through liquid chromatography-tandem mass spectrometry
• Associations were assessed at two timepoints (baseline and 1 year thereafter) and longitudinally

Pro-inflammatory E-DII score was associated with 1 microbial genera and 2 faecal metabolites.

• All associations met the false discovery rate threshold of FDR < 0.05
• Both pro- and anti-inflammatory dietary potential showed significant but asymmetric associations with microbiota composition
• The number of associated genera and metabolites was substantially larger for anti-inflammatory compared to pro-inflammatory dietary patterns (24 genera vs. 1 genus; 4 metabolites vs. 2 metabolites)

The study used the energy-adjusted dietary inflammatory index (E-DII) to measure inflammatory dietary potential, assessed via a validated 143-item food frequency questionnaire.

• The study was a longitudinal sub-study and secondary analyses nested under the PREDIMED-Plus randomized clinical trial
• 648 participants were included with data available at two timepoints: baseline and 1 year thereafter
• Participants had a mean age of 65 ± 5 years, 47% were women, and all had overweight or obesity and metabolic syndrome
• E-DII was evaluated both as a continuous variable and categorically