Cardiovascular diseases antioxidant therapy

The role of the antioxidant properties of vitamins C, E, and p-carotene in the prevention of cardiovascular disease has been the focus of several recent studies. Antioxidants reduce the oxidation of low-density lipoproteins, which may play a role in the prevention of atherosclerosis. However, an inverse relationship between the intake or plasma levels of these vitamins and the incidence of coronary heart disease has been found in only a few epidemiological studies. One study showed that antioxidants lowered the level of high-density lipoprotein 2 and interfered with the effects of lipid-altering therapies given at the same time. While many groups recommend a varied diet rich in fruits and vegetables for the prevention of coronary artery disease, empirical data do not exist to recommend antioxidant supplementation for the prevention of coronary disease. 

Vitamin E has received much publicity as one of several antioxidants that may be useful in treating a variety of disorders, including cardiovascular disease. Vitamin E may inhibit the oxidation of reduced vitamin K. Vitamin K oxidation is necessary for carboxylation of vitamin-K-dependent clotting factors, which must occur for these clotting factors to be fully functional. Increased prothrombin times, induced by combined vitamin E and warfarin therapy, may be managed by discontinuing vitamin E and, if necessary, by administering vitamin K. 

Cambridge Heart Antioxidant Study DATATOR Deprenyl and Tocopherol Antioxidative Therapy of Rarkinsonism FMC, Finnish Mobile Clinic Health Examination Survey GISSI, Gruppo Italiano Studio Soprawivenza Infarto HOPE, Heart Outcome Prevention Evaluation HPFS, Health Professional Follow-up Study NHS, Nurses Health Study PPR Primary Prevention Project SPACE, Secondary Prevention with Antioxidants of Cardiovascular disease in End-stage renal disease VEAPS, Vitamin E Atherosclerosis Prevention Study VECAT Vitamin E Cataract Age-related maculopathy Trial. 

Cardiovascular System In women, estrogen protects against cardiovascular disease. The protective cardiovascular effects of estrogen include decreased serum LDL cholesterol and increased HDL cholesterol levels, va-sodilatory effect, and antioxidation of LDL cholesterol (Chapter 20). Extensive clinical trials have shown that estrogen replacement therapy of postmenopausal women reduces the risk of heart disease. 

In the last decade, an expectation of coronary benefit had been a major reason for postmenopausal hormone use because observational studies indicated that women who use hormone therapy have a 35% to 50% lower risk of coronary heart disease than nonusers. In addition, previous studies have shown that estrogen exerts protective effects on the cardiovascular system, including lipid-lowering,antioxidant, and vasodilating effects. Nevertheless, recent randomized clinical trials have provided no evidence of cardiovascular disease protection and even some evidence of harm with hormone therapy " (Table 80-8). 

Clarke R and Armitage J (2002) Antioxidant vitamins and risk of cardiovascular disease. Review of large-scale randomised trials. Cardiovascular Drugs and Therapy 16 411 15. 

At present, numerous free radical studies related to many pathologies have been carried out. The amount of these studies is really enormous and many of them are too far from the scope of this book. The main topics of this chapter will be confined to the mechanism of free radical formation and oxidative processes under pathophysiological conditions. We will consider the possible role of free radicals in cardiovascular disorders, cancer, anemias, inflammation, diabetes mellitus, rheumatoid arthritis, and some other diseases. Furthermore, the possibilities of antioxidant and chelating therapies will be discussed. 

Structure/function claims state that a product may affect the structure or function of the body (e.g., calcium builds strong bones, antioxidants maintain cell integrity, fiber maintains bowel regularity), but may not claim that a therapy can prevent or cure a disease (e.g., alleviates constipation). Traditional nutrients refers to vitamins and minerals considered essential to the diet and/or to correct a classical nutritional deficiency disease. For example, foods containing vitamin C to correct scurvy or vitamin D to alleviate rickets are not functional foods. However, soy, w hich contains soy protein and is associated with a reduced cardiovascular risk, is a functional food. 

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