Age-related changes in adaptive mechanisms of macronutrient self-selection: evidence for a sexual dimorphism.
The effect of aging on patterns of food intake and nutrient selection was investigated using a longitudinal study. Male (n = 10) and female (n = 10) Wistar-Lou rats from 4 to 28 months of age were repeatedly submitted to a macronutrient self-selection (S-S) regimen while controls were maintained under a standard chow diet (Std). An age-related shift of preferences from CHO to fat diets, and a decrease in protein intake for both males and females were evident. Nevertheless, all these modifications were more pronounced and precocious for males. Physical exercise (45 min/day of swimming, on 6 days) induced a body weight loss and an hypophagia more pronounced for males than for females. S-S regimen results revealed that hypophagia concerned exclusively fat intake and that females significantly increased protein intake during and after the exercise period. Study of longevity curves showed a decrease of the mortality in S-S submitted male rats compared to control rats. This study shows that aging induces a sex-difference in feeding patterns which undoubtedly reveals a sex-difference metabolic requirements. Moreover, these results suggest that allowing rats to select macronutrient intakes could delay the process of senescence.
Psychophysiologie et Biochimie, EA 995, Complexe scientifique des Cezeaux, Université Blaise Pascal, Aubière, France.
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Veyrat-Durebex
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Boghossian
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Alliot
D000222:Adaptation, Physiological; D000375:Aging / Q000502:physiology*; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D001835:Body Weight / Q000502:physiology; D002149:Energy Intake; D005247:Feeding Behavior / Q000502:physiology*; D005260:Female; D008136:Longevity; D008297:Male; D005082:Physical Exertion / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D012727:Sex Characteristics; D013550:Swimming / Q000502:physiology