The Importance of Vitamin B12 in Bone Health

by L Matthews on March 8, 2014

b12 bones hip skeleton leggings

I'm sure these were intended as a handy reminder to look after your bones.

Many of those who eat a plant-based diet are aware that there are certains nutrients for which to watch out. They include: vitamin D, macromineral calcium, long-chain fatty acids like docohosexanoic acid (DHA), and vitamin B12. However, not many vegans know exactly why these nutrients are important, and that makes it all too easy to overlook signs of deficiency.

Vitamin B12 is not found naturally in plant foods, although it may be present due to bacteria in dirt on some vegetables and so forth. Many non-dairy soy beverages and other soy products, as well as almond milk, oat milk, and other vegan-friendly processed foods are fortified with vitamin B12. Certain brands of nutritional yeast are also a source of vitamin B12, but all vegans (and many non-vegans) are advised to take a daily dose of B12 from a supplement to guarantee good levels of this essential nutrient.


B12 has effects on many different aspects of health, including influencing the nervous system, immune system, cognition, cardiovascular system, and endocrine system. Describing all the ways that B12 is involved in good health would take a very long time indeed, so today I’m just going to look at one of the vitamin’s roles in the body: helping maintain bone density.

B12 and Bones
Last year, a meta-analysis of 14 cross-sectional and 13 prospective observational studies, as well as one randomized controlled trial reported taht low vitamin B12 and folate levels, and elevated levels of homocysteine, were associated with poor bone health, specifically with deterioration of bone health. Low levels of B12 were linked with bone loss in the hips of older women and that loss of bone was associated with an increased risk of fracture.

Risk of Fracture Redued with Higher B12 Levels and Lower Homocysteine
Supplemnenting with vitamin B12 helped those in four studies including 7475 people to reduce their risk of fracture by 4% for every 50mcmol/L increase in B12 levels. Conversely, in eight other studies including 11511 people, the risk of fracture increased by 4% for every mcmol/L increase in homocysteine levels.

In one 2004 study by Stone, et al., a group of women over 65 years of age had measurements taken of serum vitamin B-12, and bone mineral density of the hip and subregions, with repeat measurements of calcaneal and hip BMD taken after 5.9 and 3.5 years of follow-up. After taking into account the women’s age, weight, and clinic site, those with vitamin B-12 levels at or below 280 pg/ml had a rate of bone loss in the hip of -1.6% compared with -0.2% in women with B12 levels above 280 pg/ml (P = 0.003).

B12 Supplements
Lower B12 appears to lead to lower bone density and strength and increased fracture risk, then, giving us another reason to keep tabs on our B12 intake. As a deficiency in B12 can also cause cognitive issues (which could precipitate falls and fractures), and older people tend to have more difficulty absorbing B12 due to low stomach acid, it is an especially good idea for more elderly vegans to take a daily supplement of B12, perhaps in sublingual form.

The choice between cyanocobalamin and methylcobalamin often simply comes down to cost as the former is usually cheaper than the latter. Cyanocobalamin also seems to be the more stable form of B12 and is the one that has been more extensively studied. Smokers should choose a non-cyanocobalamin form of B12, but for most people a cyanocobalamin supplement is perfectly fine.


References
Stone KL, Bauer DC, Sellmeyer D, Cummings SR. (2004). Low serum vitamin B-12 levels are associated with increased hip bone loss in older women: a prospective study. J Clin Endocrinol Metab. Mar;89(3):1217-21.

van Wijngaarden JP, Doets EL, Szczecinska A, Souverein OW, Duffy ME, Dullemeijer C, Cavelaars AE, Pietruszka B, Van’t Veer P, Brzozowska A, Dhonukshe-Rutten RA, de Groot CP. (2013). Vitamin B12, folate, homocysteine, and bone health in adults and elderly people: a systematic review with meta-analyses. J Nutr Metab. 2013;2013:486186.

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