Mild vitamin B12 deficiency causes homocysteine levels to rise. This has been a concern for vegans who do not supplement regularly with vitamin B12 because their homocysteine tends to be at a level that has been associated with cardiovascular disease and early death.
In the past few years, however, evidence has been mounting that homocysteine-reducing therapy is not effective in reducing cardiovascular disease. Two meta-analyses, from 2010 (1) and 2013 (2) indicate that there may be no benefit from lowering homocysteine levels for cardiovascular disease.
At the same time, evidence continues to mount that elevated homocysteine can cause dementia, with a 2013 study showing that homocysteine-lowering treatment can significantly reduce brain atrophy (3).
Because of these findings, I have drastically changed the VeganHealth.org article, Mild B12 Deficiency – Cardiovascular Disease | Dementia | Birth Defects | Bone Mineral Density. It is too much to reproduce here, but I hope you will check it out!
1. Clarke R, Halsey J, Lewington S, Lonn E, Armitage J, Manson JE, Bønaa KH, Spence JD, Nygård O, Jamison R, Gaziano JM, Guarino P, Bennett D, Mir F, Peto R, Collins R; B-Vitamin Treatment Trialists\’ Collaboration. Effects of lowering homocysteine levels with B vitamins on cardiovascular disease, cancer, and cause-specific mortality: Meta-analysis of 8 randomized trials involving 37 485 individuals. Arch Intern Med. 2010 Oct 11;170(18):1622-31. | link
2. Martí-Carvajal AJ, Solà I, Lathyris D, Karakitsiou DE, Simancas-Racines D. Homocysteine-lowering interventions for preventing cardiovascular events. Cochrane Database Syst Rev. 2013 Jan 31;1:CD006612. | link
3. Douaud G, Refsum H, de Jager CA, Jacoby R, Nichols TE, Smith SM, Smith AD. Preventing Alzheimer\’s disease-related gray matter atrophy by B-vitamin treatment. Proc Natl Acad Sci U S A. 2013 Jun 4;110(23):9523-8. doi: 10.1073/pnas.1301816110. Epub 2013 May 20. | link