Siamak T. Nabili, MD, MPH
Dr. Nabili received his undergraduate degree from the University of California, San Diego (UCSD), majoring in chemistry and biochemistry. He then completed his graduate degree at the University of California, Los Angeles (UCLA). His graduate training included a specialized fellowship in public health where his research focused on environmental health and health-care delivery and management.
William C. Shiel Jr., MD, FACP, FACR
Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.
In this Article
- What is homocysteine?
- Why is it important to monitor homocysteine levels?
- What are the possible symptoms or features of elevated homocysteine levels?
- What is considered a high level for homocysteine?
- What causes elevated homocysteine levels?
- Can elevated homocysteine levels be genetic?
- Can nutritional problems cause elevated homocysteine levels?
- How common is hyperhomocysteinemia?
- How can homocysteine levels be lowered?
- How many vitamins should I take to lower my homocysteine level?
- Does lowering homocysteine levels prevent heart attacks and strokes?
- What should I do to prevent heart attacks and strokes?
- Who should undergo testing for homocysteine blood levels?
How many vitamins should I take to lower my homocysteine level?
Daily recommended doses of folate, B vitamins, and multivitamins are generally sufficient in regard to lowering homocysteine levels. These daily doses are recommended by the Food and Drug Administration (FDA) and the doses in a specific product are printed on the label of the vitamin bottle by the manufacturer. Usually, folate supplementation is recommended at 1 milligram daily; vitamin B6 is recommended at 10 milligram per day; and vitamin B12 at one-half milligram per day.
Does lowering homocysteine levels prevent heart attacks and strokes?
Currently, there is no direct proof that taking folic acid and B vitamins to lower homocysteine levels prevents heart attacks and strokes. However, in a large population study involving women, those who had the highest consumption of folic acid (usually in the form of multivitamins) had fewer heart attacks than those who consumed the least amount of folic acid. In this study, the association between dietary intake of folate and vitamin B6 and risk of heart disease was more noticeable than between dietary intake of vitamin B12 and heart disease, which was minimal.
Many other observational studies have been performed to assess the effect of folate and the other B vitamins on heart disease. Most of these studies have concluded that oral intake of folate has been associated to lower risk of heart disease, possibly because due to lowering of homocysteine levels. The relation between oral intake of vitamin B12 and B6 and heart disease was not as obvious in many of these studies. (5,6,7)
In one study, it was concluded that even in people with elevated homocysteine levels due to genetic reasons, oral intake of folate and possibly the other B vitamins was related to lower incidence of heart disease. (5,6,7)
Most of these data, however, are obtained from observational studies rather than purely controlled scientific data. Therefore, it is important to mention that despite these studies suggesting an association between the intake of these vitamins and the lower incidence of heart disease, in general, there is no compelling clinical evidence to treat hyperhomocysteinemia other than homocystinuria (the severe genetic form) in regards to heart disease, stroke, or blood clots.
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