Complementary Alternative Cardiovascular Medicine
Complementary Alternative Cardiovascular Medicine
Complementary Alternative Cardiovascular Medicine
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Chapter 5 / Vitamin Therapy and CVD 61<br />
CONCLUSION STATEMENT<br />
There is no established evidence for the use of vitamin C supplementation<br />
in CVD prevention.<br />
Vitamin E<br />
Alpha-tocopherol is the predominant lipophilic antioxidant in plasma<br />
membranes and tissue and is the most abundant antioxidant in LDL. On<br />
average, there are six molecules of α-tocopherol per LDL particle; they<br />
can function as antioxidants by trapping free radicals. In prospective<br />
studies (11,13), α-tocopherol supplementation reduced the risk of coronary<br />
events in both men and women. In the female Nurses’ Health Study,<br />
with a cohort of 87,000 women, there was an inverse association between<br />
CAD events and vitamin E intake (13). Reduced risk was seen with a<br />
vitamin E consumption of at least 100 IU/d. In a randomized, placebocontrolled<br />
study in men, the LDL oxidation kinetics in a group supplemented<br />
with 800 IU was similar to the group that received combined<br />
supplementation with 1.0 g ascorbate, 30 mg beta-carotene, and 800 IU<br />
α-tocopherol. There was a 40% decrease in the oxidation rate after 3 mo<br />
of supplementation. Plasma vitamin E levels are significantly lower in<br />
patients (both men and women) with active variant angina than in patients<br />
without coronary spasm (14). In a cohort of 34,486 postmenopausal<br />
women (10), dietary vitamin E was protective in women in the<br />
highest quintile of dietary vitamin E intake. Randomized clinical trials<br />
investigating the effect of antioxidant intake on CAD have shown mixed<br />
results. In the alpha-tocopherol, beta carotene (ATBC) Cancer Prevention<br />
Study (15,16), there was no benefit with respect to CAD for αtocopherol<br />
or β-carotene. This trial was conducted in more than 29,000<br />
Finnish male smokers. However, the dose of α-tocopherol (50 mg/d)<br />
was below the protective range suggested by the Nurses’ Health Study.<br />
In the Cambridge Heart Antioxidant Study (CHAOS), in which 2002<br />
British men and women with angiographically proved CAD were included,<br />
there was a 77% reduction in nonfatal myocardial infarction in subjects<br />
who were taking vitamin E, compared with those on placebo (17), but<br />
there was an increase in cardiovascular and overall mortality.<br />
Among the large trials, the Heart Outcomes Prevention Evaluation<br />
(HOPE) study (with 2545 women and 6996 men ≥ 55 yr) was designed<br />
to test the hypotheses that two preventive intervention strategies, namely<br />
angiotensin-converting enzyme (ACE) inhibition or vitamin E (400 IU),<br />
would improve morbidity and mortality in patients at high risk of cardiovascular<br />
events, compared with placebo for 4–6 yr. There were no significant<br />
differences between vitamin E and placebo in myocardial