Cardiovascular disease supplementation

Low levels of vitamin E have been associated with increased incidence of coronary artery disease. Observational studies have therefore suggested that supplemental a-tocopherol might have value in the treatment of cardiovascular disease. Clinical studies demonstrated contradicting results regarding the benefits of vitamin E in the prevention of cardiovascular disease. Four... 

Pham DQ, Plakogiannis R (2005) Vitamin E supplementation in cardiovascular disease and cancer prevention Part 1. Ann Pharmacother 39 1870-1878... 

Supplements of 400 Ig/d of folate begun before conception result in a significant reduction in the incidence of neural mbe defects as found in spina bifida. Elevated blood homocysteine is an associated risk factor for atherosclerosis, thrombosis, and hypertension. The condition is due to impaired abihty to form methyl-tetrahydrofolate by methylene-tetrahydrofolate reductase, causing functional folate deficiency and resulting in failure to remethylate homocysteine to methionine. People with the causative abnormal variant of methylene-tetrahydrofolate reductase do not develop hyperhomocysteinemia if they have a relatively high intake of folate, but it is not yet known whether this affects the incidence of cardiovascular disease. 

The a-tocopherol, P-carotene (ATBC) Cancer Prevention study was a randomised-controlled trial that tested the effects of daily doses of either 50 mg (50 lU) vitamin E (all-racemic a-tocopherol acetate), or 20 mg of P-carotene, or both with that of a placebo, in a population of more than 29,000 male smokers for 5-8 years. No reduction in lung cancer or major coronary events was observed with any of the treatments. What was more startling was the unexpected increases in risk of death from lung cancer and ischemic heart disease with P-carotene supplementation (ATBC Cancer Prevention Study Group, 1994). Increases in the risk of both lung cancer and cardiovascular disease mortality were also observed in the P-carotene and Retinol Efficacy Trial (CARET), which tested the effects of combined treatment with 30 mg/d P-carotene and retinyl pahnitate (25,000 lU/d) in 18,000 men and women with a history of cigarette smoking or occupational exposure to asbestos (Hennekens et al, 1996). 

HENNEKENS c H, BURNING J E, MANSON J E and STAMPFER M (1996) Lack of effect of long-term supplementation with beta-carotene on the incidence of malignant neoplasms and cardiovascular disease . New Engl J Med, 334, 1145. 

Many epidemiological studies have analyzed the correlations between different carotenoids and the various forms of cancer and a lot of conclusions converge toward protective effects of carotenoids. Many studies were carried out with (i-carotene. The SUVIMAX study, a primary intervention trial of the health effects of antioxidant vitamins and minerals, revealed that a supplementation of p-carotene (6 mg/day) was inversely correlated with total cancer risk. Intervention studies investigating the association between carotenoids and different types of cancers and cardiovascular diseases are reported in Table 3.1.2 and Table 3.1.3. 

Elevated homocysteine concentrations have been associated with an increased risk for cardiovascular disease in both epidemiologic and clinical studies.43 Several studies have evaluated the benefit of lowering homocysteine levels with folic acid supplementation. One study reported a reduction in major cardiac events with the combination of folic acid, vitamin B12, and vitamin B6 following PCI.44 However, a more recent study found an increased risk of instent restenosis and the need for target-vessel revascularization with folate supplementation following coronary stent placement.45 The role of folate in the management of IHD is currently unclear. 

Pure (3-carotene supplementation (30-50 mg per day) had no depressive effects on cardiovascular disease risk (Hennekens and others 1996 Omenn and others 1996 Lee and others 1999). 

LeeLM, Cook NR, Manson JE, Buring JE, Hennekens CH. 1999. (3-Carotene supplementation and incidence of cancer and cardiovascular disease die Women s Health Study. J Natl Cancer Inst 91 2102—2106. 

Goodman GE, Thomquist MD, Balmes J, Cullen MR, Meyskens FL, Omenn GS, Valanis B and Williams JH. 2004. The (1-carotene and retinol efficacy trial incidence of lung cancer and cardiovascular disease mortality during 6-year follow-up after stopping (5-carotene and retinol supplements. J Natl Cancer Inst 96(23) 1743—1750. 

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. 

Atkinson C, Oosthuizen W, Scollen et al. Modest protective effects of isoflavones from a red clover-derived dietary supplement on cardiovascular disease risk factors in perimenopausal women, and evidence of an interaction with ApoE genotype in 49-65 year-old women. J. Nutr. 134, 1759-1764, 2004. 

Because the potential benefits outweigh the possibilities of harm, many experts recommend a daily multivitamin that does not exceed the RDA of it component vitamins. Multivitamins ensure an adequate intake for those vitamins—folic acid, vitamin B6, vitamin B12, and vitamin D—that are most likely to be deficient. However, the the evidence is insufficient to recommend for or against the use of supplements of vitamins A, C, or E multivitamins with folic acid or antioxidant combinations for the pre vention of cancer or cardiovascular disease. Most experts recommend against the use of p-carotene supplements, either alone or in combina Don, for the prevention of cancer or cardiovascular disease. 

Flavonoids are natural dietary phytochemicals and are currently the focus of much nutritional and therapeutic interest. However, the benefit of dietary flavonoids as part of a diet or as supplements is unclear. Results of population studies suggest that adopting flavonoid-rich diets may protect against cardiovascular disease [Hertog et al., 1995 Keli et al., 1996 Knekt et al., 1996 Huxley et al., 2003 Sesso et al., 1999 Yochum et al., 1999 Hirvonen et al., 2001 ... 

In clinical trials, the preventive effect of 3-carotene supplementation on cancer or cardiovascular disease could not be demonstrated in a well-nourished population. This apparent ineffectiveness contrasts starkly with the promising results of numerous basic studies and epidemiological observations, which suggest that supplementation with this antioxidant is likely to have a protective effect. 

Many United States consumers have embraced the use of botanicals and other supplements as a "natural" approach to their health care. Unfortunately, misconceptions regarding safety and efficacy of the agents are common, and the fact that a substance can be called "natural" of course does not guarantee its safety. In fact, these products can be adulterated, misbranded, or contaminated either intentionally or unintentionally in a variety of ways. Furthermore, the doses recommended for active botanical substances may be much higher than those considered clinically safe. For example, the doses recommended for several Ma-huang preparations contain three to five times the medically recommended daily dose of the active ingredient, ephedrine—doses that impose significant risks for patients with cardiovascular disease. 

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