(The Associated Press) -- Folate and other B vitamins seem even more of a wonder drug than anyone suspected: Already known to prevent severe birth defects and heart attacks, they may also ward off broken bones from osteoporosis, two major studies suggest.

The findings underscore doctors' longstanding recommendation that people take multivitamins. They could also further support the government's decision to require bread and cereal makers to fortify their products with folate, also known as folic acid.

B vitamins are known to reduce levels of homocysteine, an amino acid already linked, at high levels, to an increased risk of heart attacks, strokes and Alzheimer's disease. Now research shows high levels of homocysteine at least double the risk of osteoporosis-related fractures.

A report from Holland found that the risk of such fractures was twice as high in men and women with homocysteine levels in the top 25 percent, compared with those with lower levels. Similarly, a U.S. study found the risk nearly quadrupled in the top 25 percent of men and nearly doubled in the top 25 percent of women, compared with the 25 percent with the lowest levels.

"The basic way to keep your homocysteine down in a healthy range is to have plenty of B vitamins," said Dr. Douglas P. Kiel, senior author of the U.S. study and director of medical research at Hebrew Rehabilitation Center for Aged Research and Training Institute in Boston.

The studies were reported in Thursday's New England Journal of Medicine.

Kiel said a standard multivitamin, taken once a day, would bring a person's homocysteine levels below the danger point. Foods naturally rich in B vitamins and calcium -- including dairy products, broccoli and other green, leafy vegetables, carrots, avocados, cantaloupes, apricots, almonds and peanuts -- can also reduce the risk of broken bones.

Since 1998, when the U.S. government began requiring that folate be added to bread, cereal and other flour products, the resulting drop in Americans' homocysteine levels has been credited with preventing about 48,000 deaths from heart attacks and strokes each year. Also, severe brain and spinal birth defects have dropped 27 percent -- the strategy's original purpose.

Researchers say it is unclear why the same benefit with fractures has not yet been documented. There is also uncertainty as to how homocysteine levels affect bone strength. The prevailing theory is that it interferes with crucial chemical bonds within the bones.

Experts say it is too soon to recommend routine testing of homocysteine levels, which can cost from $100 to $200. That is partly because the new studies do not actually prove that high homocysteine levels -- rather than some other factors -- cause weaker bones.

Kiel's research examined 825 men and 1,174 women, aged 59 to 91, who were part of the Framingham Heart Study, which since 1948 has been studying heart disease risk factors in residents of the Boston suburb. Homocysteine levels in blood samples taken from the patients between 1979 and 1982 were later measured, and the patients were followed for 12 to 15 years to see how many had hip fractures.

Hip fractures are the leading cause of elderly people being forced into nursing homes; they lead to death within a year for about 20 percent of patients, because of infections and other complications, said Dr. Felicia Cosman, clinical director of the National Osteoporosis Foundation.

Among the study participants with the highest homocysteine levels, men were about four times more likely to fracture a hip and women about twice as likely, compared with the 25 percent with the lowest levels.

"This should be another wake-up call to eat better, when you're older, especially," Kiel said.

Kiel said the highest homocysteine levels would result in about 9 extra hip fractures per 100 men and 9.5 extra fractures per 100 women over 14 years, the average time the patients were studied.

The report from Erasmus Medical Center in Holland analyzed data from two studies, one in Rotterdam and one in Amsterdam, involving a total of 2,406 people age 55 or older. Those with the highest levels were 1.9 times more likely than the others to suffer osteoporosis-related fractures.

Research reports since at least 1985 have hinted at a relationship between homocysteine and osteoporosis, said Dr. Todd Stitik, associate professor of physical medicine and rehabilitation at University of Medicine and Dentistry of New Jersey-Newark.

"This is providing more pieces to that puzzle," he said.

Stitik said that starting a healthier lifestyle even before middle age can head off problems.

Besides taking a multivitamin with folate, vitamin B12 and vitamin B6, he recommends plenty of walking or other weight-bearing exercise and eating foods rich in B vitamins.

Copyright 2004 The Associated Press. All rights reserved.