Dietary vitamin D intake and changes in body composition over three years in older adults with metabolic syndrome.

Background: Adequate intake of vitamin D through diet may offer benefits in terms of body composition.

Objectives: We aimed to evaluate the longitudinal relationship between dietary vitamin D intake and changes in body composition in older adults over one and three years under the context of a weight loss and lifestyle behavioral intervention.

Design: Longitudinal study.

Setting: Multicenter.

Participants: This longitudinal study included 715 aged participants (mean age 65.3 ± 5.0 years, 38% women) with overweight/obesity and metabolic syndrome.

Measurements: Multivariable-adjusted mixed-effects linear regression models were fitted to investigate the longitudinal associations between dietary vitamin D intake (exposure) and body composition (outcome) with available data at baseline, one, and three years of follow-up. Data on dietary vitamin D intake was assessed using a validated 143-item food frequency questionnaire. Body composition variables (total body weight (kg), total fat mass (%), total lean mass (%), muscle-to-fat mass ratio, visceral adipose tissue (kg), and android-to-gynoid fat ratio) were measured by dual-energy X-ray absorptiometry.

Results: Higher dietary vitamin D intake (for each μg/day) was associated with higher total lean mass (β: 0.10 %; 95% CI: 0.02 to 0.18; P: 0.017) and muscle-to-fat mass ratio (β: 1.00 × 10; 95% CI: 0.22 × 10 to 1.78 × 10; P: 0.011), and lower total body weight (β: -0.20 kg; 95% CI: -0.34 to -0.05; P: 0.007), total fat mass (β: -0.11 %; 95% CI: -0.19 to -0.02; P: 0.015), and visceral adipose tissue (β: -1.74 × 10 kg; 95% CI: -3.47 × 10 to -0.01 × 10; P: 0.048) at one year of follow-up in the group following the intervention in the multivariable-adjusted model.

Conclusion: Dietary vitamin D intake was associated with better body composition changes in the context of a weight loss and lifestyle intervention which led to notable changes in body composition at short term.