ABSTRACT
The trace elements copper (Cu), chromium (Cr), iron (Fe), and zinc (Zn) may all be involved in cardiovascular diseases (CVD) in humans. Suboptimal intake of Cu and Cr is associated with impaired lipid metabolism leading to an increase in risk factors associated with CVD. Known risk factors of CVD, including total cholesterol, HDL cholesterol, total cholesterol:HDL ratio, triglycerides, and circulating insulin, have all been reported to improve as a result of improved Cu and/or Cr nutrition. The beneficial effects of Cr on lipid metabolism are related to improved insulin function. Chromium also appears to mimic the action of the known antioxidant, vitamin E, in the inhibition of oxidative damage due to carbon tetrachloride toxicity in rats. Chromium has also been shown to protect against lipid peroxidation. Insufficient dietary Cu alters the antioxidant effectors of the cell, including catalase, superoxide dismutase, selenium, glutathioneperoxidase, glutathione, and Fe. Insufficient dietary Cu, coupled with an increased intake of certain simple sugars, leads to serious cardiac abnormalities in male rats but not in females. Human subjects also display abnormalities due to impaired lipid metabolism when consuming a diet low in Cu. Liver Fe is increased in animals consuming a low-Cu diet, but abnormalities in heart function are not related simply to liver Fe concentration. Chelators that bind Fe reduce oxidative damage following restricted blood flow. The effects of Fe on CVD are a function not only of its tissue concentrations but also of its valence state and of other metals and factors that control the overall cellular oxidizing potential. Intakes of Zn, less than double the RDA, may have detrimental effects on HDL cholesterol and decrease the antioxidant activity of superoxide dismutase, due perhaps to negative effects on Cu status. In summary, insufficient intake of Cr and Cu, coupled with ample intake of Fe and possibly Zn, may be related to the increased risks of CVD associated with eating Westernized diets.
