Prevention of Heart Disease in Women: Folic Acid and Homocysteine
James Meschino D.C., M.S., ROHP
In the mid to late 1960s several researchers first identified that high blood levels of homocysteine was associated with premature narrowing of arteries leading to heart attacks and related heart disease. Homocysteine is thought to increase the risk for heart disease through direct toxic effects to the cells that line our blood vessels. It increases the tendency for blood platelet cells to clump together in the bloodstream thus, obstructing blood flow. It also stimulates muscle fibers beneath the blood vessels to grow into the artery, further impairing the flow of blood. High blood levels of homocysteine is now considered to be a significant risk factor for stroke, heart attack, and reduced blood flow to fingers, toes and peripheral body parts.
Homocysteine is formed routinely by the cells of our body during the course of normal metabolism. Fortunately our bodies can recycle homecysteine by converting it into other important amino acids such as methionine, cystathionine, serine, and cysteine. However, in order to convert homocysteine into these desirable, non-toxic amino acids our bodies require an adequate intake of the B vitamins – folic acid, B6 and B12. A number of recent studies have shown that individuals with high blood levels of homocysteine can reduce their levels by supplementing their diet with folic acid, vitamin B6 and/or vitamin B12.
Reporting in the Journal of the American Medical Association (Feb. 1988) Rimm et al. demonstrated that women who supplement their diet with a multiple vitamin had a 24% lower risk of non-fatal and fatal heart attacks.
During the 14-year follow-up they documented 658 incident cases of non-fatal heart attacks and 281 cases of fatal heart attacks among the 80,082 women from the Nurses’ Health Study. After controlling for well known risk factors for heart disease they showed that high intake levels of folic acid (696 mcg./day) was associated with a 31% lower risk for heart disease episodes compared with lower folic acid intake levels (158 mcg./day). For vitamin B6 there was a 33% lower risk for heart disease episodes in subjects ingesting 4.6 mg/day compared with subjected ingesting 1.1 mg/day. For individuals with high intakes for both folic acid and vitamin B6 they experienced a 45% reduced risk for fatal and non-fatal heart attacks.
A major conclusion of this study suggests that intake of folic acid and vitamin B6 above the current recommended dietary allowance may be required to prevent heart disease.
Presently, elevated levels of homocysteine are considered to be responsible for approximately 10% of all heart attacks each year in the United States.
The current recommended dietary allowance for folic acid is 180 mcg/day for non-pregnant women. The average dietary intake in the United States among women is approximately 225 mcg./day.
Because of evidence that this level of intake may be insufficient to minimize risk of neural tube defects (i.e. spina bifida), and possibly heart disease, some experts are urging that the recommended dietary allowance (RDA) be reset to the earlier level of 400 mcg./day.
Findings from the Health Professional Follow-up Study among male practitioners demonstrated that high folic acid intake was associated with a significant reduction in heart disease risk. Thus, for both men and women high levels of folic acid intake are strongly linked to the prevention of heart disease.
In the Nurses’ Health Study each 100 mcg./day increase in folic acid was associated with a 5.8% lower risk of heart disease. It is estimated that 88-90% of the population has dietary intakes of folic acid below 400 mcg./day.
To obtain 400-700 mcg./day of folic acid is exceeding difficult to do without using a multiple vitamin supplement. Most multiple vitamin supplements contain at least 400 mcg. of folic acid. The emerging evidence continues to support the use of a daily multiple vitamin and mineral product in the prevention of heart disease, neural tube defects, certain cancers, and other conditions.
In my view, otherwise healthy adults should incorporate a well-designed multiple vitamin and mineral product into their dietary intake over and above consuming a healthy diet. The potential for this one simple intervention to prevent life threatening problems is staggering when you weigh all the evidence.
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