Folic Acid Can Reduce Risk of Stroke and Heart Disease

The evidence supporting the many health benefits of folic acid has been enhanced with the recent publication of a study in the journal Stroke. The study found that people with a dietary intake of at least 300 mcg per day of folic acid reduced their risk of stroke and heart disease by 20% and 13%, respectively, compared with those who consumed less than 136 mcg of folic acid per day.¹ After years of research confirming that pregnant women taking folic acid are less likely to have children with neural tube defects, this study is one of the first to demonstrate that dietary intake of folic acid not only reduces heart disease risk, but also prevents stroke. Stroke and heart disease are two of the top three causes of death in the United States.

The new study followed the eating habits of 9,764 men and women between the ages 25 and 74 who showed no signs of heart disease at the beginning of the study. Other trials suggest that 400 mcg per day of folic acid may prevent heart disease by lowering homocysteine levels in the blood.^{2 3 4} Homocysteine has been shown to be a significant risk factor for heart disease; the risk of having a heart attack goes up as homocysteine levels rise.

The protective effects against heart disease and stroke reinforce the benefits of supplementing with folic acid, which healthcare professionals have long known. Research has shown that women who take at least 400 mcg per day of folic acid in the early stages of pregnancy significantly reduce the risk of their children developing birth defects.^{5 6} In fact, the favorable evidence of folic acid's role in reducing the risk of neural tube defects is so strong that in 1998 the United States began fortifying grains with folic acid (140 mcg of folic acid per 100 grams of grain) and a study published last year showed that the incidence of neural tube defects has decreased since this policy was implemented. Chile also began grain fortification with folic acid in 2000.

Despite the strong evidence that supports the benefits of fortifying grain, the Food Standards Agency (FSA) of the United Kingdom recently made the decision not to add folic acid to grain products. Though the Committee on Medical Aspects of Food and Nutrition Policy in the United Kingdom estimates that grain fortification with folic acid would prevent birth defects in more than 70 children per year in the UK, the FSA decided against this action due to concerns over the long-term risks of adding folic acid to flour, including the possibility of masking a vitamin B12 deficiency or interfering with some epilepsy medications.

The concerns raised by the FSA have not been validated by the experience in the United States to date. There are currently no reports suggesting that the addition of folic acid to grains has had any detrimental consequences in adults or children. The amount of folic acid consumed by the average American is 224 mcg per day, which is just over half of the recommended dietary allowance (RDA). The concern that folic acid fortification might interfere with medications for epilepsy seems unfounded, since the amount of folic acid that has been reported to interfere with these medications (5,000 to 15,000 mcg per day) is far greater than one would obtain in a folic acid-fortified diet.^{7 8}

Good sources of folic acid include dark, green leafy vegetables such as kale, Swiss chard and mustard greens, oranges, Brewer’s yeast, soybeans, beets, asparagus, and red meat. Dietary intake can be augmented with folic acid supplements.

References:

1. Bazzano LA, He J, Ogden LG, et al. Dietary intake of folate and risk of stroke in US men and women. Stroke 2002;33:1183–9.
2. Rydlewicz A, Simpson JA, Taylor RJ, et al. The effect of folic acid supplementation on plasma homocysteine in an elderly population. Q J Med 2002;95:27–35.
3. Tice JA, Ross E, Coxson PG, et al. Cost-effectiveness of vitamin therapy to lower plasma homocysteine levels for the prevention of coronary heart disease. JAMA 2001;286:936–43.
4. Quinlivan EP, McPartlin J, McNulty H, et al. Importance of both folic acid and vitamin B12 in reduction of risk of vascular disease. Lancet 2002;359:227–8.
5. Werler MM, Shapiro S, Mitchell AA. Periconceptional folic acid exposure and risk of occurrent neural tube defects. JAMA 1993;269:1257–61.
6. Berry RJ, Li Z, Erickson JD et al. Preventing neural tube defects with folic acid in China. N Engl J Med 1999;341:1485–90.
7. Reynolds EH. Effects of folic acid on the mental state and fit frequency of drug treated epileptic patients. Lancet 1967;1:1086–8.
8. Seligmann H, Potasman I, Weller B, et al. Phenytoin-folic acid interaction: a lesson to be learned. Clin Neuropharmacol 1999;22:268–72.

Darin Ingels, ND, MT (ASCP), received his bachelor’s degree from Purdue University and his Doctorate of Naturopathic Medicine from Bastyr University in Kenmore, WA. Dr. Ingels is the author of Garlic and Cholesterol: Everything You Need to Know (Prima, 1999) and Natural Treatments for High Cholesterol (Prima, 2000). He currently is in private practice in Southport, CT, where he specializes in environmental medicine and allergies. Dr. Ingels is a regular contributor to Healthnotes and Healthnotes Newswire.

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