Folic Acid/Folate

Claims, Benefits: Prevents certain birth defects, heart disease, possibly some cancers.

Bottom Line: There is solid evidence for these claims. All women capable of becoming pregnant should get 400 micrograms of folic acid a day from a supplement, in addition to what they get from food. Other people not eating a good diet (fruits, vegetables, fortified grains and cereals) should also consider taking a multivitamin containing folic acid.

Full Article, Wellness Letter, April 2003:

The Vitamin That Does Almost Everything

Folate—also called folacin or, when used in supplements or fortified foods, folic acid—is one of the B vitamins. It is not as well known as vitamin C, but it deserves to be just as famous. Abundant in green vegetables, beans, some fruits, and wheat germ, folate is essential to the healthy division of cells and thus to fertility and healthy offspring. It is also an important factor in heart health, and may play a role in the prevention of colon, cervical, and possibly even breast cancer.

Folate = healthy mothers and babies

One folate success story started with the discovery that low blood levels of this vitamin in pregnant women can lead to neural tube birth defects, such an spina bifida and anencephaly (failure of the spine and brain to form normally), which can be disabling or fatal for the infant. These defects occur in the first days or weeks of pregnancy, before a woman can know she is pregnant. So women should start building folate stores at least several weeks before becoming pregnant. Adequate folate levels may also reduce the risk of early miscarriages. Another benefit: Pregnant women who take folic acid supplements are less likely to develop high blood pressure during pregnancy.

In 1992 the U.S. Public Health Service urged all women of childbearing age to consume at least 400 micrograms of folate daily; and in 1998 the government began to require food makers to fortify refined grain products to help meet this goal. Since then the number of neural tube defects in the U.S. has fallen by almost 25%, and about 4,000 children have been spared. And the picture will certainly continue to improve. This is a worldwide effort, not just an American one.

To be sure they’re getting enough folate, all women of childbearing age should take a multivitamin containing 400 micrograms of folic acid or eat a highly fortified cereal (a few supply 400 micrograms), as well as foods rich in folate. The folic acid from supplements and fortified foods is better absorbed than the folate that occurs naturally in foods.

Folate = healthy hearts?

Homocysteine is an interesting chemical in the ongoing puzzle of heart disease. Our bodies manufacture it, and high levels are now thought to be a risk factor for heart disease. In the normal course of things, three B vitamins (B6, B12, and folate) convert homocysteine into amino acids. If you are deficient in these vitamins, especially folate, homocysteine may build up and damage blood vessels, starting the cascade of events that lead to a heart attack. As we’ve reported (Wellness Letter, March 2001), the homocysteine theory of heart disease is still only a theory; but there’s every reason to increase your consumption of folate and other B vitamins. It might save your life.
Other news: Several small studies have shown that boosting folate intake improves blood vessel function in people who already have heart disease. And a large government study in 2002 found that people who consume the most folate have a lower risk of stroke and heart disease than those consuming little folate.

Folate = protection against cancer?

Since folate is so important in healthy cell division, it makes sense that it might prevent the unhealthy cell divisions characteristic of cancer. A high folate intake appears to play a role in reducing the risk of colon cancer, according to a recent Dutch study and other research. Diets rich in fruits and vegetables go along with a lower risk of colon cancer, and the folate in these foods may be one reason for this. There’s also some evidence that folate may help prevent cervical cancer.

As for breast cancer, the evidence for a protective effect is less convincing, but some studies have suggested that a high intake of folate may reduce the risk—but only in certain groups of women, such as heavy drinkers.

Complicating factors

Folate has some enemies. One of these is alcohol. Heavy drinking lowers your stores of B vitamins, especially folate. Thus, heavy drinking and a poor diet may increase cancer risk synergistically—that is, more than either factor would alone.

Another complicating factor for folate may be sunlight. A recent article in Scientific American cited evidence that ultra-violet radiation can actually penetrate the skin and destroy folate in the bloodstream, especially in fair-skinned people. This is another reason to avoid sunbathing.

Bottom line: The adult RDA for folate is 400 micrograms daily (600 micrograms for pregnant women). A diet rich in vegetables, fruits, and grains should supply ample amounts. Particularly good sources are leafy greens, broccoli, beans, wheat germ, whole grains, peanuts, corn, oranges, and orange juice. A cup of cooked spinach or asparagus has 260 milligrams, a cup of beans anywhere from 160 to 350. And, as we’ve said, the folic acid in supplements and fortified grain products is even better absorbed. Most multivitamins have 400 micrograms; many breakfast cereals are fortified with high levels of folic acid.

And by the way: The government has set an upper limit for folic acid from pills or fortified foods at 1,000 micrograms a day, since higher levels can worsen the neurological damage of a vitamin B12 deficiency. This is especially a problem in older people. Such high levels can also "mask" a B12 deficiency and thus delay its diagnosis and treatment.

UC Berkeley Wellness Letter, April 2003