Vitamin B12 Linked to Osteoporosis and Bone Loss in Vegetarians

Summary
Both vitamin B12 deficiency and weakening of bones are known to occur frequently in vegetarians. However, a direct association between the levels of vitamin B12 and bone weakening has not been reliably established. In this study, weakening of bones was measured by assessing the blood levels of substances called bone turnover markers (BTMs). These levels are elevated in blood whenever there is increased bone destruction. In addition, levels of vitamin D were also assessed. The researchers found that, “low vitamin B12 status is related to increased bone turnover in vegetarians which is independent from vitamin D status.”

Introduction
Weakening of bones or osteoporosis often leads to fractures, especially in the elderly. This disorder is more common among people who consume a vegetarian diet. Many earlier studies have shown that a low vitamin B12 level is associated with decreased bone density. Vitamin B12 deficiency often produces a condition called megaloblastic anemia, which is characterized by anemia and various neurological problems. In the present study, for the first time a direct association between vitamin B12 and bone metabolism was analyzed. As vitamin D markedly influences the bone turnover, its levels were also measured to understand whether vitamin D levels play any role in osteoporosis that is observed in vitamin B12 deficient individuals.

Methodology
* The study included 112 Germans and 73 Asian-Indian immigrants. Only men were included in the study. Of these, 89 were omnivores and 96 were vegetarians.
* Blood samples of all the participants were collected and were sent to Saarland University in Germany for analysis.
* Blood levels of vitamin B12, BTMs and vitamin D were measured.

Results
* The level of vitamin B12 was 156 units in German vegetarians, 279 units in German omnivores, 107 units in Indian vegetarians and 261 units in Indian omnivores.
* Irrespective of the ethnic origin, vitamin B12 deficient individuals showed higher serum concentrations of bone turnover markers (BTMs), indicating increased bone turnover.
* Vitamin D levels were low in vegetarians, but the statistical analysis showed that osteoporosis in vegetarians was independent of vitamin D concentration in their blood.

Shortcomings
The main shortcoming of this study was that it included only male participants. Also, the exact mechanism of the production of osteoporosis in vitamin B12 deficient individuals was not studied. Researchers did not collect information about vitamin D content in the diet of participants, which is an important factor that influences bone turnover.

Conclusion
This study has highlighted the role of vitamin B12 in maintaining health of bones. According to some earlier experiments, vitamin B12 stimulates bone-producing cells called osteoblasts. Dietary supplementation of vitamin B12 in vegetarians may be helpful in avoiding fractures because of osteoporosis. None of the participants of the present study had any symptom of vitamin B12 deficiency. This shows that even a minor reduction of vitamin B12 levels may be sufficient to produce osteoporosis. There is a need to measure vitamin B12 levels in pure vegans on a regular basis, so that in addition to megaloblastic anemia, even osteoporosis can be identified and prevented at the earliest.

For More Information:
Enhanced Bone Metabolism in Vegetarians: The Role of Vitamin B12 Deficiency
Publication Journal: Clinical Chemistry Laboratory Medicine, October 2009
By Wolfgang Herrmann; Rima Obeid; Saarland University, Homburg/Saar, Germany

*FYI Living Lab Reports Are Summaries of the Original Research.