Men's Osteoporosis Support GroupPlasma homocysteine and osteoporosis Eur J Nutr. 2009 Oct 7. Epub 2009 Oct 7. The association between high plasma homocysteine levels and lower bone mineral density in Slovak women: the impact of vegetarian diet. Krivošíková Z and others. PMID: 19809862. The authors state that a long-term vegetarian diet is generally poor in vitamin B, and that these vitamins, along with folate, if deficient, are related to homocysteine metabolism. It is also known that excess homocysteine (hyperhomocysteinemia) can be a risk factor for osteoporosis and fracture. See this 2004 NEMJ study by van Meurs JB and others, PMID: 15141041. This Krivošíková study, involving Slovak vegetarian women and non-vegetarian controls, evaluated the effect of vitamin B12, B6 and folate on homocysteine levels to see if there was an effect on bone mineral density (BMD) and/or bone turnover markers. Some of the significant findings were that vegetarians had significantly higher homocysteine (p < 0.001) while vitamin B12 was significantly higher in nonvegetarians (p < 0.001); there was no difference in folate levels. Additionally vegetarians had lower BMD at multiple locations. The authors conclude, "Thus, elderly women on a vegetarian diet seem to be at higher risk of osteoporosis development than nonvegetarian women." Editor's comments. Homocysteine. Elevated homocysteine levels are not only a risk factor for osteoporosis, but may be associated with many other problems, including, cardiovascular disease, Alzheimer's, birth defects, eye problems, etc. For a comprehensive review of this issue see the discussion at Veganhealth.org. And see this page for a listing of all the issues related to vitamin B12. From my reading it appears that not only vegetarians but all of us who have reached age 50 or older should probably have our homocysteine levels checked. If homocysteine is elevated, it can probably be decreased with folate or one of the B vitamins, especially B12. For long-term vegetarians or vegans at least one homocysteine testing is probably a requirement, not just something nice to have done. Reduced BMD in vegetarians. Many vegetarians/vegans don't just limit animal products in their diet, but also eat a nutrient-dense, low-fat diet. This leads to a loss of body fat and weight. BMD can decrease as a result since it fluctuates up or down with weight. That is, we do weight-bearing exercise to increase BMD. Adding body fat adds weight to our weight-bearing exercise, whereas subtracting body fat removes weight from weight-bearing exercise. So a vegan who lost weight and BMD doesn't necessarily have weaker bones, they are just less dense as they are not supporting as much body weight. The way to verify that the reduced BMD is not a sign of weaker bones is to have biochemical markers tested. The results should be in the normal range for both markers of bone formation and resorption. The word "Vegetarian." Evaluating the results of studies on vegetarians and vegans can be difficult. A vegan is someone who doesn't eat any animal products, and a vegetarian is someone who eats only some animal products. Beyond that there is little to be known about the diet of either vegetarians or vegans because there is no other strict definition of what they do eat. It is possible to be vegetarian or vegan and not eat a single vegetable or fruit. Additionally all the food eaten could be highly processed, devoid of vitamins and minerals, fiber, etc. So if a study involves vegetarians who eat mainly white bread, white rice and drink only colas how could that group be compared to vegetarians who eat mainly fresh organic fruits and vegetables, unprocessed whole grains, unprocessed starches, etc.? We won't have really good results from clinical studies until more descriptive terms than "vegan" or "vegetarian" are used when discussing the food intakes of test subjects in studies. But what the Krivošíková study discussed in this Update does mean for vegetarians is that if they don't supplement their diet with vitamin B12 and don't eat a "healthy" diet, they should consider themselves as having high homocysteine levels and low vitamin B12 levels until they prove otherwise. Those older vegetarians who do supplement with vitamin B12 and eat a healthy diet should likely still have at least one homocysteine test done. Based upon the results then have retests done as warranted. There is a simple way to find out if your diet provides proper nutrition. Download, install and use the free computer program CRONoMeter to evaluate the food you eat. If you have any questions on its use just email me. Bottom line. Elevated homocysteine should be considered a risk factor for osteoporosis. Have yours tested if in doubt after reading the guidance in the Veganhealth.org discussions.
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