Abstract MP54: Dietary Protein Lowers Obesity Risk in Middle-Aged Framingham Offspring Study Adults
Aging triggers increases in fat mass and changes in body composition. Since dietary protein may impact the balance of lean/fat mass, it has been suggested that current Dietary Guidelines for protein may be inadequate for older adults. Using data from the Framingham Offspring Study, we examined the role of dietary protein on body mass index (BMI), waist size, and risks of obesity and excess central adiposity in middle-aged adults. Dietary data were derived from 3-day records collected in exams 3 and 5 in 1490 subjects, ages 30-54 years who were free of diabetes, CVD and cancer. Protein intakes (total, animal, and plant) were expressed as weight-adjusted residuals to minimize potential confounding by body size. BMI and waist circumference were measured at each exam. Analysis of covariance (ANCOVA) was used to estimate mean follow-up BMI and waist size while controlling for the following potential confounders: age, sex, education, height, activity, smoking, total energy intake, % energy from fat, and baseline weight. Multiple logistic regression models were used to determine the effect of protein intake on obesity and central adiposity risks, while adjusting for the above potential confounders. Adjusted protein intakes were classified into tertiles, with mean intakes of 0.9, 1.2, and 1.5 grams/kg of body weight across these tertiles. BMI declined with increasing total, animal, and plant protein intakes for both men and women (p<0.05 for all). Overall, those in the highest tertile of total protein intake, had a BMI that was 2.4 kg/m2 lower than those in the lowest tertile (p<0.0001). Results for men and women separately were very similar. The highest (vs. lowest) tertile of animal and plant protein intakes were associated with 1.3 kg/m2 and 2.6 kg/m2 lower BMI, respectively (p<0.0001, for both). Waist size also declined (Men: 39.9, 38.2, 37.7 inches; Women: 32.8, 31.8, 30.6 inches; p-trend<0.0001) with increasing tertile of total protein intake. Among non-obese subjects at baseline, incident obesity risk was 35% lower (95% CI: 0.43-1.00) in the highest (vs. lowest) tertile of total protein intake. Both animal and plant proteins lowered obesity and central adiposity risks although the results were somewhat stronger for plant than for animal protein. Finally, the effects of dietary protein intake as part of a healthier diet pattern (e.g., in combination with higher fruits and vegetables, fiber, and whole grain intakes) were explored. In these analyses, the beneficial effects of protein on obesity risk did not differ in those with higher (O.R.: 0.76; 95% CI: 0.61, 0.95) vs. lower (O.R. 0.78; 95% CI: 0.63, 0.97) intakes of fruits and vegetables. The same was true for fiber and whole grain intakes. In Framingham, higher dietary protein intakes lowered the long-term risk of obesity in middle-aged adults.
Author Disclosures: J. Buendia: None. S. Hasnain: None. M. Bradlee: None. M.R. Singer: None. R.B. D'Agostino: None. L.L. Moore: None.
- © 2015 by American Heart Association, Inc.