While women are about four times more likely than men to develop weak, porous, osteoporotic bones, men can also suffer a decline in bone strength over time. A recent study has linked low bone mineral density in both men and women with vitamin B12 deficiency, although the mechanism behind the relationship isn’t fully understood. The researchers examined vitamin B12 status and indicators of bone health in 2,576 men and women aged 30 to 87 who are participating in the Framingham Osteoporosis Study.

Participants with plasma levels of vitamin B12 below 148 picomoles per liter (pM/L) were found to be at greater risk for developing osteoporosis than those with higher levels. Some experts consider plasma B12 levels below 185 pM/L to be “very low.”

The recommended daily allowance for vitamin B12 is currently set at 2.4 micrograms for both men and women. Animal-based foods such as fish, beef, pork, milk, and cheese are generally good sources. But because B12 is often not well absorbed by older persons, those above age 50 are encouraged to consume fortified foods or take B12 supplements. Katherine L. Tucker, Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston, Massachusetts; phone (617) 556-3351, e-mail hatherine. tucker@tufts.edu.