beta-carotene, carotenoids and the prevention of coronary heart disease

The importance of low density lipoprotein (LDL) oxidation to the atheroscle rotic process has led to the examination of beta-carotene as a possible pre ventive agent. Several epidemiologic studies show an inverse association be tween serum/adipose beta-carotene levels and coronary heart disease risk. R andomized clinical trials, however, have not shown any benefit, and perhaps even an adverse effect, of beta-carotene supplementation. A number of poss ible confounding factors may explain the inconsistency between the trials a nd epidemiologic evidence. Other carotenoids that are correlated with beta- carotene both in the diet and in the blood might be important factors, as m ight other plant-derived compounds. Alternatively, low serum carotenoid lev els may reflect either increased lipoprotein density or the presence of inf lammation, both factors emerging as important novel risk factors for corona ry heart disease. Whereas the trial results support no preventive role for beta-carotene, the epidemiologic evidence does generally support the idea t hat a diet rich in high carotenoid foods is associated with a reduced risk of heart disease.