The association between dietary inflammatory index, muscle strength, muscle endurance, and body composition in Iranian adults

PURPOSE: Dietary factors may modulate inflammation status which contributed to the various chronic diseases like sarcopenia. Therefore, we aimed to examine the association of dietary inflammatory index (DII) and muscle strength (MS), muscle endurance (ME), and body composition.

METHODS: This cross-sectional study was conducted in 270 adults living in Tehran, Iran. The DII was calculated using a validated food frequency questionnaire. Body composition (fat-free mass (FFM), fat mass (FM), percent body fat (PBF), skeletal muscle mass (SMM)) was measured using body composition analyzer. Anthropometric measures (weight, body mass index (BMI), waist circumference (WC)), were done. MS was measured by a digital handgrip dynamometer in both right (MSR) and left (MSL) hand. Mean of MSR and MSL was considered as MS.

RESULTS: A significant decrease was found for MS (p < 0.01) and MSR (p < 0.01) across tertiles of DII. Participants who had greater scores of DII also had lower MER (p < 0.01), even after adjustment for confounding factors (age, sex, education status, income, smoking, physical activity, body mass index and energy intake) (p < 0.02). Adherence to DII was significantly related to MSL (p < 0.01), ME (p < 0.01), and ME of the MEL (p = 0.02) in the crude model, which was disappeared after controlling for covariates. Those in the third compared to the lowest tertile of DII, had no significant difference in mean of FFM (p < 0.001), SMM (p < 0.001), and WC (p < 0.001).

CONCLUSIONS: Higher DII scores were associated with less muscle strength and endurance among Iranian adults. Further studies are needed to confirm the veracity of our results.

LEVEL OF EVIDENCE: Descriptive cross-sectional study, Level V.