Coronary Artery Disease
- Rimm EB, Willett WC, Hu HB, et al [ Harvard Med School, Boston]
Folate and Vitamin B6 From Diet and Supplements in Relation to Risk of Coronary Heart Disease Among Women
JAMA 278: 359-364, 1998
The relationship between intake of folate and vitamin B6 and coronary heart disease [CHD] in women is being investigated. Low intake of these vitamins has been linked with hyperhomocysteinemia, but has yet to be linked with fatal CHD and nonfatal myocardial infarction [MI].
In a prospective cohort study, information was gathered on food consumption from 80,082 women who were then followed up for 14 years and cases of nonfatal MI and fatal CHD were documented. The women who completed the original survey had no history of diabetes, hypercholesterolemia, cardiovascular disease, or cancer. Test subjects were classified into quintiles for intake of folate and vitamin B6. Adjustment was made for age.
A total of 658 cases of nonfatal MI and 281 of fatal CHD were documented within the test group. Data were controlled for smoking, hypertension, alcohol, fiber and vitamin E consumption, and the various fats [saturated, polyunsaturated, and trans]. Comparing quintiles 1 [lowest intake] and 5 [ highest intake], the relative risk [RR] was 0.69 [95% confidence interval-CI-, 0.55 to 0.87] for folate and 0.67 [95% confidence interval 0.53 to 0.85] for vitamin B6.
Multivitamins, vitamin B6 and folate reduced the risk of CHD in women. Women who had one drink a day also had lower risk of CHD than nondrinkers.
- Omenn GS, Beresford SAA, Motulsky AG, [ Univ of Washington, Seattle]
Preventing Coronary Heart Disease : B Vitamins and Homocysteine
Circulation 97: 421-424, 1998
A new study from the European Concerted Action Projects suggests that homocysteine, plasma folate, and vitamin B6 have significant effects on the risk of atherosclerotic cardiovascular disease. Total homocysteine level had a striking dose-response relationship with risk of peripheral vascular and coronary heart disease. However, the study leaves many questions about the relationship between folate, vitamin B12, vitamin B6, and total homocysteine [tHey]; the effect of homocysteine on cardiovascular risk; and the recommended risk reductions for individuals and patients. These questions are addressed in an editorial.
Homocysteine, B vitamins, and coronary heart disease risk :- The available evidence suggests that a total homocysteine level of greater than 15 m mol/L is associated with a 1.4 relative risk of coronary heart disease mortality, compared with levels less than 10 m mol/L. For disease prevention, total homocysteine levels should be reduced to a range of 9 to 10 m mol/L. This reduction and an accompanying increase in circulating folate levels is unlikely to be achieved by diet alone. The bioavailability of folic acid from dietary congugated folates is about one half of that from supplements. Folic acid supplementation of 400 mg /L or greater is already recommended to prevent birth defects. The addition of vitamin B12, 200 to 1000 mg, would prevent adverse outcomes even for those subjects who lack intrinsic factor for B12 absorption. However, prevention trials are still needed to prove a cause-and-effect relationship and to rule out adverse effects.
The available evidence strongly suggests that folic acid supplementation may reduce mortality from coronary heart disease, taken with vitamin B12 supplements sufficient to assure adequate absorption even in the absence of intrinsic factor.