Biomedical subjects
A S Nicolas
Publications and source records attributed to A S Nicolas.
Diet-related prevention of Alzheimer's disease: different hypotheses.
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The nutritional intake of a free-living healthy French population : a four-year follow-up.
OBJECTIVE: To contribute to a better definition of the nutritional requirements of the healthy elderly and to improved knowledge the effects of age on these requirements. METHODS: We studied the nutritional intake of 96 elderly persons who had met criteria of good health status in 1993 at a four-year interval. The nutritional intake of the elderly subjects who remained healthy during the four-year interval (18 men and 64 women), was considered to globally correspond to their nutritional needs. The nutritional intake was evaluated by a three-day food record. RESULTS: The mean baseline weight of the subjects who remained in good health during the four years was 72,6 +/- 9,5 kg for men and 60,1 +/- 9,3 kg for women. In four years, mean weight remained globally stable. But in cross-sectional analysis, weight tended to decrease with the age of the subjects. This decrease was significant for women in 1993. Mean baseline intake was nearly 29 kcal/kg. Longitudinal and cross-sectional analyses showed that it changed only slightly with age. Though global energy intake varied slighlty in four years, we have observed some changes in the composition of this caloric intake. For men and women, protein intake tended to decrease in four years (respectively -0,4% and -0,6%), carbohydrate intake to decrease (respectively -1,1% and -2,7%) and fat intake to increase (respectively +2,1% and +2,9%). These variations were not significant except for fat and carbohydrate intakes in women. In 1993, for a majority of subjects, the intakes of iron, and vitamins C and B12 were higher and the intakes of calcium, zinc, vitamins A, B1, B6 and B9 were lower than the French recommendations. In four years, mean intake did not change significantly, except for calcium intake in women (-8,8%). CONCLUSION: In this study, healthy aging was associated with a mean caloric intake close to 29 kcal/kg which is near the upper limits of recommendations (between 25 and 30 kcal/kg/d). These intakes, like those of macronutrients and micronutrients changed little with advancing age. These results suggest that the needs of the elderly remain quite stable with aging. Nevertheless a tendency to weight loss with aging is observed, especially in older subjects, suggesting that even if food intake contributes to the maintenance of healthy aging, aging processes are multidimensional and frailty that is often associated with weight loss is ineluctable for older subjects.
Caloric restriction and aging.
Caloric restriction in species with a short life span has shown it can increase median and maximum life expectancy and reduce or delay the onset of most age-related diseases. The remarkable reproducibility of the phenomenon irrefutably proves its validity and makes caloric restriction one of the most frequently studied paradigms in experimental research on aging.
Nutrition and successful aging: a study of 520 elderly persons from the Toulouse and New-Mexico Aging Process Study.
Epidemiological studies of aging are usually confronted with the presence of numerous pathologies or environmental factors which make it difficult to identify the effects of aging individually. One way of reducing the variability among individuals is to use well defined criteria to select the study population. This is the choice that was made for the New Mexico and Toulouse Aging Process Studies, which were particularly turned towards successful aging. In this study we have sought to explain the diversity of states of health of the subjects of these two studies by means of an aging classification exploring the medical history, balance and walking, and the cognitive functions. This reveals that the poorer health of certain subjects (about 10% and 30% of the populations of Toulouse and Albuquerque respectively) is slightly associated with changes in eating behaviour relative to subjects who age successfully. We have, however observed a decrease in vitamin E intake in Toulouse associated with a reduction of lipids in the food. But the poorer state of health is predominantly explained by advancing age and the occurrence of pathological states. This study confirms that aging was generally successful in the two populations studied.