Bone health

Key vitamins for bone health — vitamin B₁₂ (cobalamin)

by Dr. Susan E. Brown, PhD

Because of their role in the detoxification of homocysteine, vitamins B6, B12, and folic acid have all been recently added to our list of important bone-protecting nutrients. Osteoblasts, the body’s bone-building cells, require an adequate supply of B12, or their ability to function properly will be compromised. Vitamin B12 deficiency anemia has been associated with osteoporosis, and having low serum levels of vitamin B12 has also been associated recently with odds of frailty in older women.

Following careful analysis of the Framingham Offspring Study in 2000, Tufts nutritional epidemiologist Katherine Tucker concluded that B12 deficiency may be more widespread than previously thought, with nearly 40% of the US population “flirting” with marginal B12 status, according to the USDA website.

Vitamin B12 is not found in plants, but is abundant in animal protein. Yet vitamin B12 deficiency in the US may be largely linked not so much to inadequate meat, poultry and fish intake — the foods that supply the majority of dietary B12 — but to problems with intestinal absorption. Of interest is that researchers have found intestinal malabsorption to be a problem among the young and the old alike. The problem may lie with inadequate stomach acid, which is required to cleave the vitamin from the animal proteins to which it is tightly bound in food sources. In older folks, the problems with B12 absorption could be due to a loss of active acid-secreting cells in the stomach as we age. But in younger adults, Tucker speculates that the problem could be resulting from the overuse of antacid tablets.

B12 is also one of the few vitamins biosynthesized by the “friendly” flora in our intestines. Though production in the human intestines is not believed to occur to any great degree, there is still a lot for us to learn about both B12 synthesis and absorption processes, and it is safe to say that maintaining healthy gut flora is one way to encourage adequate vitamin B12 status as well as promote good bone health. After all, the B12 we get from animal sources originally derives from bacterial production, for instance in the rumen of cows.

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Last Modified: 04/18/2011
Principal Author: Dr. Susan E. Brown, PhD