THE EFFECT OF A LOW CAROTENOID DIET ON MALONDIALDEHYDE-THIOBARBITURICACID (MDA-TBA) CONCENTRATIONS IN WOMEN - A PLACEBO-CONTROLLED DOUBLE-BLIND-STUDY

Objective: The purpose of the study was to evaluate the effect of a lo w carotenoid diet (83 mu g beta-carotene) on malondialdehyde-thiobarbi turic acid (MDA-TBA) concentrations of nine pre-menopausal women. Meth ods: Subjects lived on the metabolic research unit of the Western Huma n Nutrition Research Center (WHNRC), where diet, exercise and other ac tivities were controlled. Five subjects (Group C, control group) consu med a low carotenoid diet and received an additional 0.5 mg/day of bet a-carotene while four subjects (Group P,placebo group) received only t he low carotenoid diet during days 1 to 60 period 1). All subjects rec eived 0.5 mg/day of beta-carotene during days 60 to 100 (period 2), pl us three capsules/day mixed carotenoid supplement (Neo-Life Company) d uring study days 100 to 120. Changes in MDA-TBA concentrations were an alyzed during the study periods and between the groups, Results: At th e start of the study (day 1), no significant difference in the MDA-TBA concentration was observed between the control (Group C) and the plac ebo (Group P) subjects. During period 1 (days 2 to 60), when Group P s ubjects consumed the low carotenoid diet without supplementation. the MDA-TBA values for Group P rose markedly and were significantly (p<0.0 5) higher than the MDA-TBA values for Group C subjects who were receiv ing carotenoid supplementation. During period 2 (days 60 to 100) when both groups received carotenoid supplementation, the MDA;TBA values of Group P subjects were significantly (p<0.05) reduced to the point whe re they were similar to the MDA-TBA values for Group C subjects. Concl usions: These findings provide evidence to support the beneficial effe cts of carotenoids in preventing lipid peroxidation in the cells. Furt her studies are needed to identify the exact mechanism by which carote noids prevent lipid peroxidation and the amount needed for normal acti vity.