Complementary Alternative Cardiovascular Medicine

Chapter 5 / Vitamin Therapy and CVD 65
A prospective, double-blind, randomized trial with a combination of
1 mg of folic acid, 400 µg vitamin B 12, and 10 mg of pyridoxine or
placebo administered to 205 patients for 6 mo after successful coronary
angioplasty demonstrated that vitamins significantly reduced Hcy levels
and decreased the rate of restenosis and the need for revascularization of
the target region (40). The extension of this study (41) provided data to
show that Hcy-lowering therapy with folic acid, vitamin B 12, and pyridoxine
was effective in controlling excessive restenosis mechanisms 1
yr after successful coronary angioplasty. The benefit obtained obtained
at 6 mo was maintained at 1 yr, despite cessation of the vitamin therapy
at 6 mo. The authors recommend this combination of vitamins as an
adjunctive therapy for patients who are undergoing coronary angioplasty.
In a study investigating the association of serum Hcy levels, as well
as folate and vitamin B 12 levels, to the rate of in-stent restenosis after 6
mo did not show a relationship (42).
CONCLUSION STATEMENT
Some cohort studies show an inverse relationship between folate status
(dietary folate, serum folate) and serum total homocysteine and risk
for CHD. No RCT have been completed to determine the outcome of
folate supplementation on incidence of MI, stroke or death from CVD.
Grade II The conclusion is supported by fair evidence.
VITAMINS AND ENDOTHELIAL FUNCTION
The vascular endothelium is the primary site of dysfunction in many
diseases, particularly CVD. Research suggests that vitamins E and C and
folic acid have beneficial effects on vascular endothelial function in
patients who are at high risk of CVD, as well as in healthy people (43).
These studies used 300 IU, 600 IU, or 1000 IU of vitamin E or 500 mg,
1 g, or 2 g of vitamin C. The studies showed a decrease in monocyte
adhesion or an improvement in flow-mediated dilation (FMD) of the
brachial artery. A randomized, crossover study of 25 men and 25 postmenopausal
women showed that degradation of endothelial function
after the acute high-fat meal ingestion was mitigated by a concomitant
ingestion of 800 IU of vitamin E (44).
Most studies support a role for vitamins C and E in the improvement
of endothelial function in healthy subjects (45), as well as patients with
diabetes (46) or lipid abnormalities (47). Similar effects of chronic consumption
of vitamins E or C on endothelial function have not been
demonstrated. Therefore, the clinical significance of these acute effects
is not clear.