INFLUENCE OF COMBINED ANTIOXIDANT NUTRIENT INTAKES ON THEIR PLASMA-CONCENTRATIONS IN AN ELDERLY POPULATION

Data from a cross-sectional survey of 746 noninstitutionalized, Boston -area elderly individuals (aged greater than or equal to 60 y) were an alyzed to assess the relation between antioxidant nutrient intake and plasma antioxidant status. Intakes of vitamin C and carotenoids and su pplemental vitamin E were estimated by using 3-d diet records. Mean pl asma concentrations of these nutrients were calculated within categori es of intake, and polynomial contrasts were used to test for linear tr ends of the plasma nutrient concentrations across these categories. Ad justments for the corresponding intake of the plasma nutrient under co nsideration, as well as age, sex, and smoking status were made to mini mize potential confounding. Plasma alpha-tocopherol concentrations wer e 188 greater in individuals consuming greater than or equal to 220 mg vitamin C/d compared with those with intakes < 120 mg/d (P for trend < 0.001). Plasma carotenoid concentrations were 13% higher across incr easing categories of vitamin C intake (P for trend = 0.002). An increa sing intake of carotenoids was moderately associated with higher plasm a alpha-tocopherol (P for trend = 0.008) and unrelated to ascorbic aci d status. An increasing intake of supplemental vitamin E was weakly co rrelated with plasma ascorbic acid (P for trend = 0.05) and unrelated to carotenoid status. These results provide epidemiologic evidence tha t increasing intake of either vitamin C, vitamin E, or carotenoids is associated with greater plasma concentrations of one or both of the ot her antioxidant vitamins and not associated with any impairment in ant ioxidant status.