Rating

	My Rating: 3 ratings 5 stars (3) 4 stars (0) 3 stars (0) 2 stars (0) 1 stars (0)

Email

	Email this page to a friend Friend's Email: Your Name: Your Email: Enter the code shown: Submitting Send Email

Vitamin C

It is known that a diet enriched with vitamin C containing fruits and vegetables may lower the risk of CAD. Vitamin C and other antioxidants may reduce CAD by trapping free radicals and consequently preventing tissue damage within blood vessels.²¹

Unfortunately, few clinical trials have examined vitamin C alone as a potential treatment for CAD. Prior to 2007, studies utilized vitamin cocktails containing vitamin C to treat the patients. These trials generally failed to find a CV benefit of these vitamin cocktails.²¹  However, one large meta-analysis pooled data from nine trials  and found that vitamin C supplementation at 700 mg/day was associated with a 25% reduction in CAD risk.²¹

The Physicians’ Health Study II in 2007 examined the effect of 14, 641 healthy physicians supplemented  with 500 mg of vitamin C. Vitamin C had no effect on  the development of MIs, CV mortality, or hemorrhagic stroke during this eight-year study.²¹ Similar results were shown by Losonczy et al. in 1996,²² and by the Women’s Antioxidant Cardiovascular study in 2007.²³  In 2002, Kurl et al. examined vitamin C levels and the development of stroke and hypertension in 2,419 healthy middle-age men. Low vitamin C levels were associated with an increased risk of stroke. In subjects with hypertension, low vitamin C further increased the risk of stroke.²⁴ In contrast, Kushi et al. (1996) examined 34,486 healthy post-menopausal women over seven years and found no association of vitamin C and CAD prevention.²⁵

As with CoQ, the relationship between vitamin C and CAD is unclear and needs further investigation before recommendations can be made regarding taking vitamin C to prevent CAD.

Vitamin D

Vitamin D deficiency is present in 30-50% of the general population. Epidemiologic studies have suggested that poor vitamin D status is associated with poor CV outcomes in renal failure patients with CAD.  In renal failure patients with CAD, severe vitamin D deficiencies led to a three to five fold increased risk of dying from sudden death or heart failure.²⁶  In 2008, Pilz et al. also noted that low levels of vitamin D were associated with myocardial dysfunction, sudden cardiac death, and death due to heart failure.²⁷ In 2010, Bair et al. reported that men and women with low vitamin D levels who took vitamin D supplements for one year had a reduced risk of developing CAD, heart failure, or death from heart disease.²⁸ In contrast, Bolland et al. in 2007 administered  calcium plus vitamin D supplements to 36,282 women, irrespective of baseline vitamin D levels. After seven years, calcium supplementation with or without vitamin D supplementation was shown to  increase the risk of MIs and stroke compared to subjects not taking calcium.²⁹  Thus, calcium supplementation, but not vitamin D, was seen as a potential risk to the patients’ CV health.  

The Institute of Medicine currently recommends a daily intake of 400-800 IU of vitamin D for adults for good health. In light of conflicting data, no guidelines have been made regarding vitamin D and the prevention of CAD.²⁸

Vitamin E

As with CoQ, vitamin E is of interest regarding CAD because it is also found in the LDL complex. In in vitro studies, vitamin E inhibits LDL oxidation. In patients with ischemic heart disease, vitamin E levels vary inversely with the degree of CAD.²¹ 

Vitamin E is a lipophilic molecule located deep within the LDL core.³⁰ Evidence that vitamin E functions as an antioxidant has not been compelling. Vitamin E’s antioxidant effect has been demonstrated in animal models with mild atherosclerotic disease. In human studies, however, atherosclerotic heart disease is typically more advanced, limiting the potential benefit that vitamin E treatment might offer.³⁰

In 1993, Stampfer et al. evaluated 85,000 women and monitored vitamin E intake and CV status. Over eight years, patients with the highest vitamin E plasma levels had a 43% lower risk of developing CAD compared to patients with normal levels.³⁰  Rimm et al. in 1993 evaluated the  risk of CAD in 39,910 men who took vitamin E supplements and found that taking at least 100 IU per day for two years reduced their risk of CAD.³⁰

The Alpha–Tocopherol, Beta Carotene Cancer Prevention Trial (ATBC) in 1994 studied 29,000 male smokers treated with low dose vitamin E (50 IU/day), 20 mg of beta carotene, the combination of the two, or placebo for up to eight years. Vitamin E treatment produced no effect on the risk of CAD, but increased the  risk of death from hemorrhagic stroke, presumably by impairing platelet aggregation.³¹ In contrast, the Cambridge Heart Antioxidant Study (CHAOS 1996)examined higher dose vitamin E treatment (400 or 800 IU/day) in CAD patients and found that vitamin E reduced their risk of MI’s and CV events by 77% and 47% respectively.³¹

Once again, randomized clinical trials have not provided clear and sufficient evidence to recommend the use of vitamin E as a preventive treatment for CAD.

Conclusion

Of the vitamin and dietary supplements discussed above, none have undergone adequate  clinical trials to unequivocally prove that they can  reduce the risk of CAD. Thus, fish oil, folic acid, CoQ, and the vitamins C, D, and E all still warrant further investigation before the American Heart Association  can recommend them to prevent CAD.

Continued on next page >