Comparison of two levels of vitamin C supplementation on antioxidant vitamin status in elderly institutionalized subjects.

The concentrations of antioxidant vitamins, particularly vitamin C, are often low in the plasma of institutionalized elderly subjects, and could explain their susceptibility to oxidative stress. However, as such low levels were not always found in home-living healthy elderly persons, the antioxidant vitamin depletion in the formers could result from environmental conditions better than aging itself. The objective of this study was therefore to verify the antioxidant vitamin status in institutionalized elderly persons and to evaluate if a low vit C supplement could be sufficient to improve the plasma vit C concentration in those subjects. This study confirms that plasma vitamin C levels are in the scurvy range in 20 elderly institutionalized subjects and significantly lower than in healthy home-living elderly persons. Beta-carotene concentrations were found marginally low but alpha-tocopherol levels were in the normal range. All three vitamins were correlated. Fifteen days on a physiological vitamin C (150 mg/day) supplementation was sufficient to restore normal vit C levels (50 mumol/l). A further pharmacological vit C administration (750 mg/day) during 30 days only allowed a marginal increase in the plasma vit C concentrations.

Disturbed galactose metabolism in elderly and diabetic humans is associated with cataract formation.

Lactose consumption has been associated with a high incidence of cataract in northern Indian and southern Italian populations. Galactose absorbed after hydrolysis of lactose from milk in individuals with normal lactase activity is considered responsible. However, lactase-deficient subjects who often avoid drinking milk are able to digest lactose and absorb free galactose in fermented milk and yogurt. This study was conducted to evaluate the relationships between milk and yogurt consumption, galactose metabolism and cataract risk. Milk ingestion was dose-related with cataract risk in lactose digesters (particularly in diabetics) but not in lactose maldigesters. Conversely, yogurt intake had a protective dose-effect on cataract formation for the whole population. Maximal galactose concentrations after an oral galactose test increased exponentially with age. Red blood cell galactokinase activity was significantly lower in elderly subjects (> 60 y) than in young individuals (P < 0.05), and galactose-1-phosphate uridyl-transferase activity was significantly lower in institutionalized subjects and in home-living elderly with cataract than in healthy elderly subjects (P < 0.05). We conclude that the cataractogenic action of milk lactose is dependent on the disturbance of galactose metabolism in elderly subjects and that yogurt is not cataractogenic, although the mechanism of the protective effect of yogurt remains unknown.