For a list of selected food sources sorted by vitamin B12 content, visit this web page at ARS' Nutrient Data Laboratory, and scroll down to "Vitamin B12."
Women are about four times more likely than men to develop osteoporosis, or weak, porous bones. But a new study links vitamin B12 deficiency with low bone mineral density in men, and confirms similar, previously reported findings in women.
Researchers funded by the Agricultural Research Service (ARS) reported the findings in the Journal of Bone and Mineral Research. The study was led by epidemiologist Katherine Tucker with the Jean Mayer USDA Human Nutrition Research Center on Aging (HNRCA) at Tufts University in Boston, Mass. Tucker directs the HNRCA's Dietary Assessment and Epidemiology Research Program.
While vitamin B12 deficiency has been linked with low levels of markers of bone formation, the mechanism behind the relationship is not known.
The scientists examined the relationship between vitamin B12 blood levels and indicators of bone health measured in 2,576 men and women, aged 30 to 87, participating in the Framingham Osteoporosis Study. They found that those with vitamin B12 levels lower than 148 picomoles per liter (pM/L) were at greater risk of osteoporosis than those with higher levels. Plasma B12 levels below 185 pM/L are considered "very low," according to some experts.
The study found that those with vitamin B12 concentrations below 148 pM/L had significantly lower average bone mineral density--at the hip in men, and at the spine in women--than those with concentrations above.
The range of symptoms of B-12 deficiency includes anemia, balance disturbances and cognitive decline. Osteoporosis usually progresses with no outward effect until a fracture occurs.
The recommended dietary allowance for vitamin B12 is 2.4 micrograms per day for both men and women. Low stomach acid and aging can lower the ability to absorb the vitamin. Those over age 50 are encouraged to consume fortified foods or supplements containing B12.
This study suggests adequate vitamin B12 intake is important for maintaining bone mineral density. Animal protein foods, such as fish, liver, beef, pork, milk and cheese are good sources of vitamin B12.
ARS is the U.S. Department of Agriculture's chief scientific research agency.