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The Effects of a Higher Protein Intake During Energy Restriction on Changes in Body Composition and Physical Function in Older Women

The Effects of a Higher Protein Intake During Energy Restriction on Changes in Body Composition... Background.The purpose of this double-blind randomized clinical trial was to compare the relative effectiveness of a higher protein and conventional carbohydrate intake during weight loss on body composition and physical function in older women.Methods.Thirty-one overweight or obese, postmenopausal women (mean SD: age 65.2 4.6 years, body mass index 33.7 4.9 kg/m2) were prescribed a reduced calorie diet (1,400 kcal/day; 15%, 65%, 30% energy from protein, carbohydrate, and fat, respectively) and randomly assigned to 2 25 g/day whey protein (PRO n 15) or maltodextrin (CARB n 16) supplementation for 6 months. Lean soft tissue (LST) via dual-energy X-ray absorptiometry; thigh muscle, subcutaneous adipose tissue (SAT), and intermuscular adipose tissue with magnetic resonance imaging; knee strength with isokinetic dynamometry; balance and physical function with a battery of performance tests.Results.PRO lost more weight than CARB (8.0% 6.2%, 4.1% 3.6%, p .059; respectively). Changes in LST, %LST, and strength, balance, or physical performance measures did not differ between groups (all p > .05). Weight to leg LST ratio improved more in PRO versus CARB (4.6 3.6%, 1.8 2.6%, p .03). PRO lost 4.2% more muscle (p .01), 10.9% more SAT (p .02), and 8.2% more intermuscular adipose tissue (p .03) than CARB. Relative to thigh volume changes, PRO gained 5.8% more muscle (p .049) and lost 3.8% greater SAT (p .06) than CARB. Weight to leg LST ratio (r2 .189, p .02) and SAT (r2 .163, p .04) predicted improved up and go, relative muscle (r2 .238, p .01) and SAT (r2 .165, p .04) predicted improved transfer test, and %LST predicted improved balance (r2 .179, p .04).Conclusions.A higher protein intake during caloric restriction maintains muscle relative to weight lost, which in turn enhances physical function in older women. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png The Journals of Gerontology Series A: Biomedical Sciences and Medical Sciences Oxford University Press

The Effects of a Higher Protein Intake During Energy Restriction on Changes in Body Composition and Physical Function in Older Women

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Publisher
Oxford University Press
Copyright
The Author 2011. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.
Subject
Journal of Gerontology: MEDICAL SCIENCES
ISSN
1079-5006
eISSN
1758-535X
DOI
10.1093/gerona/glr120
pmid
21798863
Publisher site
See Article on Publisher Site

Abstract

Background.The purpose of this double-blind randomized clinical trial was to compare the relative effectiveness of a higher protein and conventional carbohydrate intake during weight loss on body composition and physical function in older women.Methods.Thirty-one overweight or obese, postmenopausal women (mean SD: age 65.2 4.6 years, body mass index 33.7 4.9 kg/m2) were prescribed a reduced calorie diet (1,400 kcal/day; 15%, 65%, 30% energy from protein, carbohydrate, and fat, respectively) and randomly assigned to 2 25 g/day whey protein (PRO n 15) or maltodextrin (CARB n 16) supplementation for 6 months. Lean soft tissue (LST) via dual-energy X-ray absorptiometry; thigh muscle, subcutaneous adipose tissue (SAT), and intermuscular adipose tissue with magnetic resonance imaging; knee strength with isokinetic dynamometry; balance and physical function with a battery of performance tests.Results.PRO lost more weight than CARB (8.0% 6.2%, 4.1% 3.6%, p .059; respectively). Changes in LST, %LST, and strength, balance, or physical performance measures did not differ between groups (all p > .05). Weight to leg LST ratio improved more in PRO versus CARB (4.6 3.6%, 1.8 2.6%, p .03). PRO lost 4.2% more muscle (p .01), 10.9% more SAT (p .02), and 8.2% more intermuscular adipose tissue (p .03) than CARB. Relative to thigh volume changes, PRO gained 5.8% more muscle (p .049) and lost 3.8% greater SAT (p .06) than CARB. Weight to leg LST ratio (r2 .189, p .02) and SAT (r2 .163, p .04) predicted improved up and go, relative muscle (r2 .238, p .01) and SAT (r2 .165, p .04) predicted improved transfer test, and %LST predicted improved balance (r2 .179, p .04).Conclusions.A higher protein intake during caloric restriction maintains muscle relative to weight lost, which in turn enhances physical function in older women.

Journal

The Journals of Gerontology Series A: Biomedical Sciences and Medical Sciences – Oxford University Press

Published: Nov 27, 2011

Keywords: Dietary protein Weight loss Body composition Physical function Older women

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