Folic Acid

Folic acid plays a key role in helping prevent anemia and certain types of birth defects. New research evidence has now found that this B vitamin can also play a role in decreasing the risk of heart disease. What's encouraging about folic acid's laudatory talents is that they don't rely on megadose amounts. You can get all the folic acid you need from a healthy diet. But, unfortunately, surveys indicate that folic-acid-containing foods are apparently in dangerously short supply on the average U.S. plate. The best food sources for folic acid include dark green leafy vegetables; citrus fruit such as oranges; tomatoes; strawberries; beans; liver; peanuts; and folic-acid-fortified cereals.

What's so special about folic acid?

The body is in a constant state of flux, with cells being replaced on a regular basis. The raw material for this cellular "turnover" comes, in part, from the body's own recycling system and partly from newly received materials. Folic acid, also called folate, is a key ingredient in a type of construction shuttle service that moves the body's single carbon "bricks" from one compound to another. Folate also plays a role in the synthesis of DNA and RNA, the genetic material involved in cell division and reproduction.

As you would imagine, when the construction of new cells and tissues goes awry, or is forced to slow down, there can be serious repercussions.

When folate is in short supply, one of the first places where problems occur is in the blood. In cellular terms, the life span of the doughnut-shaped red blood cell is relatively short, each cell being replaced every 120 days. Because of this short life span, they are among the first cells in the body to suffer from a folic acid deficiency. Without folate, red blood cells are not made in sufficient numbers, and a type of anemia results.

Giving a folic acid supplement or adding folate-rich foods can bring about a dramatic recovery in those suffering from a folate-deficiency anemia.

The outlook, however, isn't as promising if there's a folate deficiency during pregnancy.

Following conception, the developing fetus begins to lay down the groundwork for many bodily systems. One of the first to develop is the nervous system, and folic acid plays a key role. The catch, though, is that folate must be present during the first few weeks after conception – a time at which most women are unaware they're even pregnant. If there's insufficient folate during this crucial period, mistakes can be made in the formation of the nervous system. Unfortunately, no amount of folate can make up for these structural abnormalities, once that period has passed. Spina bifida is a type of birth defect in which one or more of the vertebra of the spinal column fail to develop properly. It affects approximately 1 out of every 1,000 babies born. It is estimated that as much as 75 percent of all cases of spina bifida are attributable to a folate deficiency during those first few weeks of pregnancy. This makes it especially important for all women to have adequate folic acid in their diets before the pregnancy even begins. The problem is that less than half of all pregnancies are planned.

The U.S. Public Health Service recommends that all women of childbearing age who are capable of becoming pregnant should make sure they consume at least 400 micrograms of folic acid per day. The second National Health and Nutrition Education Survey (NHANES II) of food consumption found the average folic acid intake to be 200 micrograms per day – half of the Public Health Service guideline amount.

Scientists have discovered that if the body doesn't have enough folic acid, a chemical called homocysteine begins to accumulate. A number of studies have indicated that, as the level of homocysteine rises, so to does the risk of heart disease.

A recent study in the New England Journal of Medicine looked at 1,041 elderly men and women. The scientists at the USDA's Human Nutrition Research Center on Aging at Tufts University found that those with the highest levels of homocysteine in their bloodstream were twice as likely to have significant narrowing of the arteries in the neck, amounting to as much as a 25 percent loss of the inner diameter. Such a decrease in blood flow would be a serious harbinger to heart disease and stroke.

To help reduce all these serious yet avoidable health risks, the government has mandated the fortification of enriched cereal grains with 140 micrograms of folate for every 100 grams (3.5 ounces) of grain. This is twice the level needed to replace the folate that is lost during milling. The cereal grains affected include the flours from wheat, rice, corn, rye, barley, triticale, and buckwheat, as well as cornmeal, rice, farina, and macaroni or pasta.

A study in the American Journal of Public Health affirmed how grain fortification could prevent hundreds of birth defects every year. Efforts must be made to ensure that folate-rich foods make a regular appearance at the table. It is also the reason why we indicate those foods that provide at least 40 micrograms of folate per serving with the letter "F" in our FAC column.

More on: Nutritional Resources for Families

Excerpted from:

From The Nutrition Doctor's A-to-Z Food Counter. Copyright © Ed Blonz, 1999. Used by arrangement with NAL Signet, a member of Penguin Group (USA) Inc.

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