Title

Plasma and lipoprotein tocopherol and carotenoid concentrations in the elderly: Results from the Framingham Heart Study cohort

Date of Completion

January 1996

Keywords

Gerontology|Health Sciences, Nutrition

Degree

Ph.D.

Abstract

The aims of the current study were to (i) investigate factors that affect in vitro low-density lipoprotein (LDL) oxidizability, (ii) establish antioxidant concentrations in the elderly and (iii) examine the relationship between plasma and lipoprotein antioxidant concentrations and coronary heart disease (CHD) in the Framingham Heart Study (FHS) cohort.^ In study one, the effects of fatty acid composition of reduced fat diets on LDL antioxidant concentrations and in vitro LDL susceptibility to oxidation in moderately hypercholesterolemic older adults were examined. Reduced fat diets compared to a Western type diet resulted in the formation of LDL particles less susceptible to oxidation. Further, among the reduced fat diets, LDL was most resistant to oxidation after diets rich in monounsaturated fatty acids (olive or canola oil diets) and least resistant after diets high in polyunsatuated fatty acids (corn oil diet).^ In study two, reference ranges for tocopherol, retinol and carotenoid (lutein/zeaxanthin, cryptoxanthin, lycopene, $\alpha$- and $\beta$-carotene) concentrations for subjects aged 65 years and older were established. The study included 638 participants of the FHS cohort apparently free of cardiovascular diseases and cancer. In multivariate analyses plasma cholesterol and triacylglycerol concentrations and total intake of vitamins E and C predicted 64% and 55% of plasma $\alpha$-tocopherol concentrations in men and women, respectively. Important determinants of carotenoid concentrations included gender, plasma cholesterol concentrations, body mass index (negative correlation), smoking status (negative correlation), and dietary carotene.^ In study three, the relationship between plasma antioxidants, including tocopherols, retinol and the carotenoids, and the prevalence of CHD and cerebrovascular disease (CVD) in participants of the FHS cohort was investigated. Men with plasma and high-density lipoprotein (HDL) $\alpha$-tocopherol concentrations in the lowest quartiles had significantly increased odds ratios for CVD (odds ratio (OR) = 4.04; 95% CI: 1.26, 12.88; OR = 5.06; 95% CI: 1.4, 18.3, respectively). In women with moderate hypertriglyceridemia (200-400 mg/dL), low HDL $\alpha$-tocopherol concentration was significantly associated with increased risk for CHD (OR = 2.36; 95% CI: 1.03-5.39), independent of other cardiovascular risk factors. Plasma or lipoprotein carotenoid concentrations were not associated with an increased risk for CHD or CVD in this study population in a case control analysis. ^