Homocysteine (cont.)
What should I do to prevent heart attacks and strokes?
Losing excess weight,
exercising regularly, controlling diabetes and high
blood pressure, lowering the bad LDL
cholesterol, and
stopping cigarette smoking
are crucial steps in preventing heart attacks and strokes. The association
between homocysteine levels and atherosclerosis is generally weaker compared to
the known risk factors of diabetes, high blood pressure (hypertension), high
cholesterol level, and cigarette smoking.
It is recommended that healthy adults eat more fresh fruits and vegetable,
eat less saturated fat and cholesterol, and take one multivitamin daily. One
multivitamin will supply 400 mcg (microgram or one-one thousandth of a gram)/day
of folic acid in addition to vitamins B6, B12, and other important vitamins.
Who should undergo testing for homocysteine blood levels?
Some doctors screen for elevated homocysteine levels in patients with early
onset of blood clot formation, heart attacks, strokes, or other symptoms related
to atherosclerosis, especially if these patients do not have typical risk
factors, such as smoking cigarettes, diabetes, high blood pressure, or high LDL
cholesterol levels.
Currently, there are no official recommendations as to who should undergo
testing for homocysteine blood levels. Before more scientific data become
available from the currently ongoing studies, many experts do not recommend
a screening test for blood homocysteine levels, even in patients with unexplained
blood clot formation. In addition, the consensus recommendation is against
treating elevated homocysteine levels with vitamins to prevent heart disease.
There is also no consensus as to the optimal dose of folic acid and other B
vitamins for the treatment of elevated blood homocysteine levels. (For example,
treatment of patients with high homocysteine levels may require higher doses of
folic acid and other B vitamins than the amounts contained in a multivitamin.)
Therefore, a decision regarding testing should be individualized after
consulting with your doctor.
References:
1. Ray, JG. Meta-analysis of hyperhomocysteinemia as a risk factor for
venous thromboembolic disease. Arch Intern Med 1998; 158:2101.
2. den Heijer, M, Rosendaal, FR, Blom, HJ, et al. Hyperhomocysteinemia and
venous thrombosis: a meta-analysis. Thromb Haemost 1998; 80:874.
3. Vermeulen, EG, Stehouwer, CD, Twisk, JW, et al. Effect of
homocysteine-lowering treatment with folic acid plus vitamin B6 on progression
of subclinical atherosclerosis: a randomised, placebo- controlled trial. Lancet
2000; 355:517.
4. Eikelboom, JW, Lonn, E, Genest, J Jr, et al. Homocyst(e)ine and
cardiovascular disease: a critical review of the epidemiologic evidence. Ann
Intern Med 1999; 131:363
5. Robinson, K, Arheart, K, Refsum, H, et al. for the European COMCAC Group.
Low circulating folate and vitamin B6 concentrations. Risk factors for stroke, peripheral vascular disease, and coronary artery disease. Circulation 1998;
97:437.
6. He, K, Merchant, A, Rimm, EB, et al. Folate, vitamin B6, and B12 intakes
in relation to risk of stroke among men. Stroke 2004; 35:169.
7. McNulty, H, Dowey le, RC, Strain, JJ, et al. Riboflavin lowers
homocysteine in individuals homozygous for the MTHFR 677C->T polymorphism.
Circulation 2006; 113:74.
Previous contributing author: Dennis Lee, M.D.
Last Editorial Review: 8/8/2008
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