Expert: Florence M Rollwagen - 1/2/2009

Question
Elevated levels of Homocysteine has been shown to significantly raise the risk of cardiovascular disease. It has also been shown that the three vitamins; Folate, B6, and B12 lower the homocysteine levels in the body, thereby reducing the risk for cardiovascular disease. Yet the government has concluded that it is premature to add these vitamins to the Dietary Recommended Intake (or DRI the official recommended eating habits). Why is this so?

Answer
Hi David:  Thanks for your question.  An excellent question, and one that drives to the heart of government recommendations for our health.  Let me give you a few examples before getting to your question.  First, the government advises us not to smoke because of lung cancer, right?  But do all smokers develop lung cancer?  Do all people with lung cancer smoke?  No to both.

Second, we are advised to lower salt intake because it can raise blood pressure, right?  But elevated blood pressure due to salt is a problem for only a small portion of the population, so why do we all have to cut back?

It is very risky for a government led "one size fits all"  approach to health recommendations.  This is largely because of statistics and individual variation.  Statistics are based on population studies, and are never black and white.  There will always be outliers.

OK, now to your question.  The short answer is that nobody really knows what are the correct biomarkers for cardiovascular disease (CVD).  First, we thought it was elevated cholesterol, then we thought it was LDL, now we think it's homocysteine.

It is still not shown that homocysteine is a sufficient biomarker for CVD.  What this means is that just because elevated homocysteine levels are associated with CVD, we don’t know whether the elevation is a symptom or a cause.  The only direct evidence relating homocysteine levels to CVD comes from persons with a rare recessive disease called homocsyteinuria, in which the genes for homocysteine synthesis are mutated.  Artificially elevating serum homocysteine levels reduces their risk of developing disease.  
http://www.quackwatch.org/03HealthPromotion/homocysteine.html

It is very likely that other contributing factors feed into CVD that are unrelated to homocysteine levels.

There are studies in which elevated homocysteine levels do not correlate with CVD.

For:  http://www.ncbi.nlm.nih.gov/pubmed/19118243?ordinalpos=1&itool=EntrezSystem2.PEn...

Other factors:
http://www.ncbi.nlm.nih.gov/pubmed/19106185?ordinalpos=7&itool=EntrezSystem2.PEn...

Marginal: http://www.americanheart.org/presenter.jhtml?identifier=4677

http://jama.ama-assn.org/cgi/content/abstract/281/19/1817

You can search the medical literature yourself by going to: http://www.ncbi.nlm.nih.gov/PubMed/

You can search for homocysteine levels and CVD, as well as other biomarkers for CVD such as CRP (an inflammatory marker).   Actually, there is good evidence that elevated CRP (C-reactive protein) is also a good marker for CVD:
http://www.medscape.com/viewarticle/445763

I know this seems confusing, but there is really no consensus among the medical studies showing that elevated homocysteine levels are a predictor for CVD.

I should add that although the government isn't recommending B vitamins at this stage, they do recommend a diet high in fruits and vegetables, with lower levels of lean meat and fish.  A great recommendation for everyone.  And one that is high in B vitamins.  Just remember what Hippocrates said:  "Let thy food be thy medicine"

Hope this helps.  Write back if you have more questions.

FM Rollwagen, PhD