Homocysteine levels high enough to cause adverse health effects are considered dangerous. Homocysteine is a metabolite of methionine, an amino acid. Under normal circumstances it is harmless; however, high levels are associated with increased risk of heart disease, dementia and Alzheimer's disease. Your body uses B vitamins to keep homocysteine levels in a safe range. Your physician can perform and interpret a homocysteine test to determine whether your levels are dangerously high.
Homocysteine Regulation
Your body regulates cysteine by converting it to other substances. It is converted to the enzyme cystathionine b-synthase (CBS), then to cystathionine, followed by cysteine, an amino acid that protects cells by acting as an antioxidant. This conversion, particularly the one to CBS, is B-6-dependent. Another method of regulation is by accelerating homocysteine conversion to methionine, which is dependent on 5-methyltetrahydrofolate and methylcobalamin, the active forms of folic acid, or B-9 and B-12.
Dementia and Alzheimer's Disease
According to a study published in the February 2002 issue of the "New England Journal of Medicine," elevated homocysteine blood levels are an independent risk factor for dementia and Alzheimer's disease. The study found that elevated homocysteine levels preceded the onset of dementia in 83 of 111 individuals. The study also found that if you have a plasma homocysteine level greater than 14 μl. per liter, your risk of Alzheimer's disease nearly doubles.
Cardiovascular Disease
Having high homocysteine levels increases your risk of cardiovascular disease, which is the primary cause of death in the United States. According to the American Academy of Family Physicians, studies indicate elevated homocysteine levels are associated with an independent risk for fatal and nonfatal cardiovascular disease. As of 2006, the American Heart Association estimates more than 81 million people in the U.S have one or more forms of cardiovascular disease. Lowering homocysteine protects your heart.
Lowering Homocysteine
Elevated homocysteine is primarily associated with B vitamin deficiency. However, homocystinuria, a rare genetic disorder, can cause elevated homocysteine, 20 times higher than normal. According to the Linus Pauling Institute, studies indicate high doses of vitamin B-6, B-12 and folic acid, or B-9, help lower homocysteine levels if you have homocystinuria. An additional nutrient, betaine, is helpful as well.
Dietary Sources
If you eat a diet rich in B vitamins, your chances of having elevated homocysteine are reduced. Protein-rich foods, including meat, poultry, fish and eggs, are the best sources of B vitamins. Beans are another source of B vitamins. If you are vegetarian or vegan, you are at risk of B vitamin deficiency, particularly B-12.
Safety
It is important to consult your doctor regarding recommended solutions if your homocysteine levels are high. Vitamin supplementation should not negate traditional medical treatment. Because all supplements can cause side effects and interactions, consult your doctor before taking B vitamins, especially in high doses.
References
- Linus Pauling Institute: The Vascular Toxicity of Homocysteine and How to Control It; Mark F. McCarty, Ph.D et al.; November 1999
- "New England Journal of Medicine," Plasma Homocysteine as a Risk Factor for Dementia and Alzheimer's Disease; Sudha Seshadri et al.; February 2002
- AAFP.org: Homocysteine Levels and Cardiovascular Disease; Richard Sadovsky M.D; September 1999
- AmericanHeart.org: Cardiovascular Disease and Statistics
