Increased risk of cardiovascular disease at suboptimal plasma concentrations of essential antioxidants: an epidemiological update with special attention to carotene and vitamin C

For the prolongation of life expectancy and reduction of ischemic heart disease (IHD) dietary guidelines generally recommend lowering saturated mammalian fat with partial replacement by vegetable oils and increasing generously vegetables, legumes, and fruits, which provide more essential antioxidants. Plasma antioxidants as assayed in epidemiological studies of complementary type (ie the cross-cultural MONICA Vitamin Substudy reevaluation considering the “Finland-Factor”, the Edinburgh Angina-Control Study, and the Basel Prospective Study) consistently revealed an increased risk of IHD (and stroke) at low plasma concentrations of antioxidants, with the rank order as follows: lipid-standardized vitamin E ⪢ carotene = vitamin C > vitamin A, independently of classical IHD risk factors. Decreasing IHD risk through nutrition may be possible when plasma concentrations have the following values: > 27.5–30.0 µmol vitamin E/L, 0.4–0.5 µmol carotene/L, 40-50 µmol vitamin C/L and 2.2–2.8 µmol vitamin A/L. Thus, previous prudent regimens may now be updated, aiming at an optimal status of all essential and synergistically linked antioxidants.