Goodbye to folic acid deficiency?

A scan of the Canadian population reveals that, thanks largely to fortified foods, almost no one is deficient in folic acid, and forty percent have relatively high - maybe even too high - levels of the B vitamin in their blood.

Despite the lack of deficiency, however, 1 in 5 women of childbearing age did not carry in their blood the amount of folate (the natural form of folic acid) recommended to prevent birth defects, the benefit for which the vitamin is best known.

So while many men, the elderly, and children may have a lot of folic acid, Canadian women of childbearing age often don't have enough, and should continue to take supplements, study author Cynthia Colapinto of the Children's Hospital of Eastern Ontario Research Institute told Reuters Health.

"I believe all women of childbearing age should take supplements," she said.

These findings are "reassuring," said Dr. Nicholas Wald, director of the Wolfson Institute of Preventive Medicine, who did not participate in the study. He cautioned that people should not focus on the high levels of folate found in the study, since there is still no evidence that these levels can cause problems.

"It is a mistake to talk about dangerously high levels of folate," Wald said in an e-mail to Reuters Health. "The important message is that folic acid fortification has worked and has been shown to be successful in improving health without evidence of harm."

Folate is the natural form of the B vitamin, found in foods such as spinach, asparagus, dried beans and peas, and orange juice; folic acid is the synthetic form used in vitamin supplements and added to certain "fortified" foods, including wheat flour and breakfast cereals.

Experts say that women need extra amounts of the vitamin to reduce the risk of having a baby with neural tube defects - birth defects of the brain or spine, including spina bifida.

As a result, in the late 1990s, the U.S. and Canada mandated that folic acid be added to products such as flour to help prevent neural tube defects. It's also added to enriched cereal, pasta, corn meal and other grains. Since this change, the rate of neural tube defects in Canada has dropped by 46 percent.

To more closely investigate the effects of fortification, Colapinto and her team directly measured folate concentrations in the blood of 5,248 Canadians between the ages of 6 and 79, who were representative of the population as a whole.

The recommended daily intake of folate from all sources is 150 micrograms (mcg) for children ages 1 to 3; 200 mcg for ages 4 to 8; and 300 mcg for ages 9 to 13. Older teens and adult women and men are advised to get 400 mcg.

There is no established maximum recommended amount of folate. To estimate one here, Colapinto and her colleagues looked for people with circulating folate levels above those seen in the top 3 percent of Americans in a recent nationwide survey. That level, 600 nanograms per milliliter (ng/mL) of blood, is 50 percent higher than the 400 ng/mL experts consider optimal for women to prevent neural tube defects in their babies.