Do protein and energy intakes explain long-term changes in body composition?

Area of Science:

• Gerontology
• Nutritional Science
• Body Composition Research

Background:

• The impact of dietary protein and energy on short-term body composition changes is established.
• However, the role of diet in long-term, age-related body composition shifts remains unclear.

Purpose of the Study:

• To investigate long-term associations between dietary protein and energy intake and age-related changes in body composition.
• To identify if short-term dietary effects on body composition persist over longer durations.

Main Methods:

• Utilized longitudinal data from 608 healthy Chinese adults (aged 50-69) from the 1993 and 1997 China Health and Nutrition Surveys.
• Employed sex-specific regression models to assess baseline protein (% energy) and energy (kJ) intake predicting changes in mid-arm muscle area (MAMA) and waist circumference (WC).

Main Results:

• Observed sex-specific U-shaped associations: higher energy intake linked to greater WC gain and less MAMA loss; higher protein intake linked to less MAMA loss.
• In males, energy intake below 95% RDA associated with smaller WC gain and greater MAMA loss.
• Protein intake below 10.4% energy linked to greater MAMA loss for both sexes; excessive energy intake (>125% RDA) in females linked to greater body fat gain.

Conclusions:

• Dietary patterns, specifically protein and energy intake, appear to significantly influence age-related body composition changes.
• Findings suggest that maintaining adequate protein and appropriate energy intake may be crucial for preserving body composition during aging.