High homocysteine levels increase the risk of cardiovascular disease (strokes and heart attacks) and can be reduced by folic acid and vitamin B12 (cyanocobalamine).   A study by Spanish doctors published in Headache found elevated homocysteine levels in patients who have migraines with aura.  Patients who have migraine with aura are known to have increased risk of cardiovascular disease and it is possible that elevated homocysteine levels are at least in part responsible for this risk.  I routinely check homocysteine, vitamin B12 and folic acid levels in all of my patients.  One caveat is that vitamin B12 levels are not very reliable – you may have a normal level, but still be deficient.  While laboratories consider a level of over 200 to be normal, clinical deficiency is often present at levels below 400.  A single case report has been published of a severe deficiency with neurological symptoms and a vitamin B12 level of over 700.  This patient lacked the ability to transport vitamin B12 from his blood into the cells.  Injections of high doses of vitamin B12 corrected the problem.  Oral magnesium supplementation is not as effective as injections because vitamin B12 is poorly absorbed in the stomach.   Other ways to get vitamin B12 is by taking it sublingually (under your tongue) or by a nasal spray (it requires a prescription and is fairly expensive).  Many of my patients a willing to self-inject vitamin B12, which they do anywhere fro once a week to once a month.   Vegetarians are more likely to be deficient since meat (and liver) are the main sources of vitamin B12.  Smokers are also at a high risk because cyanide in smoke binds to vitamin B12.