Short-term protein and energy supplementation activates nitrogen kinetics and accretion in poorly nourished elderly subjects123

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ABSTRACT

Background:

An increase in protein intake exerts a stimulating effect on protein kinetics in children, young adults, and healthy elderly persons. However, there are few data on the response to such dietary changes in malnourished elderly subjects, despite important medical implications in this population.

Objective:

The objective of this study was to determine the metabolic response to short-term nutritional supplementation in moderately malnourished elderly subjects.

Design:

The influence of 10 d of supplementation (1.67 MJ/d and 30 g protein/d) on body composition, resting energy expenditure, and whole-body protein kinetics was studied in 17 malnourished elderly patients and 12 healthy young adults. A control group of 6 malnourished elderly patients received no supplementation.

Results:

Supplemented elderly subjects had a significantly greater fat-free mass gain than did unsupplemented elderly subjects (1.3 and 0.1 kg, respectively; age effect, P < 0.05; diet effect, P < 0.02) and a significantly greater increase in fasting rate of protein synthesis than did young supplemented subjects (0.6 and 0.2 g·kg FFM−1·11 h−1; age effect, P < 0.05). The net protein balance in the supplemented elderly subjects in the fed state was positively correlated with protein intake (r2 = 0.46) and in the fasted state was negatively correlated with protein intake (r2 = 0.27). The sum of these regressions is a line with increasingly positive net diurnal protein balance produced by increasing protein intake.

Conclusion:

These data provide evidence of a short-term anabolic response of protein metabolism to dietary supplementation in malnourished elderly patients that is likely to improve muscle strength and functional status.

KEY WORDS

Elderly subjects
short-term nutritional supplementation
protein-energy malnutrition
body composition
basal metabolic rate
protein turnover
protein accretion
nitrogen isotopes
France

Cited by (0)

1

From the Institut National de la Recherche Agronomique (INRA), Unité de Nutrition Humaine et de Physiologie Intestinale, Institut National Agronomique Paris-Grignon (INA PG), Paris; the Service de Gastro-entérologie, Hôpital Avicenne, Bobigny, France; the Centre d’évaluation des Maladies Osseuses, Hôpital Cochin, Paris; and the Service d’Endocrinologie-Diabète-Nutrition, Hôpital Jean Verdier, Bondy, France.

2

Supported by BSA, Danone Group.

3

Address reprint requests to C Bos, INRA, Unité de Nutrition Humaine et de Physiologie Intestinale INA PG, 16 rue Claude Bernard, 75231 Paris cedex 05, France. E-mail: [email protected].