By Sally Squires
Washington Post Staff Writer
Wednesday, April 8, 1998; Page A01

The National Academy of Sciences recommended for the first time yesterday that large segments of the population take vitamins.

All women of childbearing age should take a daily folic acid supplement to cut the risk of serious birth defects, and all older adults should take daily vitamin B12 supplements to guard against anemia, the academy recommended.

Although both vitamins are available naturally in foods, the academy took this step because even people who eat a well-balanced diet may have difficulty getting all the nutrients they need from food alone.

"For women to meet the daily recommendation for folate, they would have to eat a loaf of bread a day," said Godfrey P. Oakley Jr., director of the division of birth defects and developmental disabilities at the federal Centers for Disease Control and Prevention.

While most standard multivitamins contain enough folic acid to meet the recommended daily intake of 400 micrograms, not all contain enough vitamin B12 to meet the needs of those over age 50 -- 2.4 micrograms per day.

The revised recommendations are part of an ongoing overhaul of the well-known "recommended dietary allowances." The recommendations, which are now called dietary reference intakes, serve as the basis for a healthy diet.

Last fall, the academy called for many children and older women to eat more foods rich in calcium as a way to protect their bones. But this is the first set of recommendations that calls for Americans to take vitamins to get the nutrients that they need.

"This is truly a landmark recommendation because in the past there has been such a bias against recommending supplements," said Bonnie Liebman, director of nutrition for the Center for Science in the Public Interest (CSPI), a Washington-based consumer group. "Experts have been afraid that people will take supplements and use it as an excuse to eat a lousy diet. But you can't use that fear to hide the scientific evidence. We know that a supplement works and when you are talking about birth defects, why take chances?"

At the same time, the academy acknowledged the growing and sometimes dangerous trend of taking megadoses of vitamins and set the first safe upper limits for niacin, vitamin B6 and folic acid. Excess amounts of those nutrients can cause various problems, including flushing, itching, numbness and even crippling nerve damage.

The report also establishes the first recommendations for the essential nutrients biotin and choline and updates guidelines for vitamins B6, riboflavin, niacin and pantothenic acid.

"Today's report represents a major step in revising and updating recommended intakes of folate, other B vitamins and choline for the United States and Canadian populations," said Surgeon General David Satcher.

B vitamins are life-sustaining nutrients that help safeguard the brain and nervous system. Increasing scientific evidence suggests that B vitamins may also play important roles in reducing the risk of cardiovascular disease, cancer and certain types of psychiatric or mental disorders.

Based on evidence that folic acid protects against spina bifida and other so-called neural tube defects, the Public Health Service (PHS) began recommending in 1992 that women of childbearing age consume 400 micrograms of the vitamin per day. But the PHS urged women to get folic acid from food, mainly by eating more fruits, vegetables and whole grains.

To help achieve that goal, the Food and Drug Administration has required since Jan. 1 that bread, pasta, flour, crackers, breakfast cereal, rice and many other foods be enriched with folic acid. But the fortification only provides an additional 100 micrograms per day.

"Research over the past decade strongly indicates that women capable of becoming pregnant should eat a varied diet and also take extra folic acid, especially in the month just prior to conception and the first month of pregnancy," said Roy M. Pitkin, who chaired the academy committee that wrote the guidelines.

Vitamin supplements are also the best way for Americans 51 and older to be sure that they consume enough vitamin B12, according to the recommendations. Between 10 percent to 30 percent of older Americans lose their ability to absorb vitamin B12 from food -- which can cause anemia, a chronic condition that can lead to serious health problems.

"Why this happens is unclear, but it is important to prevent vitamin B12 deficiency in people of this age," Pitkin said. "Therefore, we recommend that adults over age 50 meet most of their recommended intake with synthetic B12 from fortified food and vitamin supplements."