One of the essential sulfur-containing amino acids, the nutrient methionine is important for many bodily functions, including immune cell production and proper nerve function. Dietray methionine is a potent antioxidant and an important amino acid for your liver’s repair and rebuilding processes.
If you’re pregnant, remember that methionine, along with folic acid, plays a role in neural-tube (part of the fetus that forms during cell development and becomes the nervous system) defect in the fetus. Methionine is an essential amino acid important for the normal closure of the neural tube, and research shows that methionine deficiency is associated with a higher occurrence of neural-tube defects (nervous system problems such as spina bifida) in newborns.
Vegetarians are much more likely to be deficient in methionine than meat-eaters are.
The following are some key uses of methionine:
Methionine forms cysteine, which helps form glutathione enzymes that help detoxify chemicals and free radicals. However, health practitioners recommend cysteine more often than methionine as an antioxidant, because it provides a wider range of protection and people tolerate it better.
By supplying sulfur, methionine helps prevent skin and nail problems.
Methionine prevents excess fat buildup.
Methionine helps relieve or prevent fatigue.
Because it reduces histamine release, methionine may be useful in some allergy cases.
Research shows that methionine supplementation may be helpful in treating Parkinson’s disease.
Don’t take extra methionine if you have elevated cholesterol or heart disease, rheumatoid arthritis, or if you eat meat often. Methionine converts to homocysteine, a known risk factor for heart disease. Like many nutrients, you must remember the bottom line: enough, but not too much.
Homocysteine is an amino acid by-product of methionine breakdown. Too much homocysteine in your blood is a risk factor for developing hardening of the arteries and having a heart attack or stroke. Elevated levels of homocysteine may also increase your risk of other degenerative processes in the eyes, nervous system, and kidneys.
Some people have a genetic predisposition for creating too much homocysteine and cannot properly convert this toxic byproduct back to methionine so that their bodies can use it. Even children can experience this problem, causing hardening of the arteries at a young age. A deficiency of folic acid, vitamin B-6, and vitamin B-12 can all lead to the same condition.
People who eat lots of red meat take in extra methionine and are more likely to be deficient in these vitamins, increasing their risk for heart disease. Many nutritionists today recommend taking extra vitamin B-12 (400 mcg per day) and folic acid (400 mcg per day), and some recommend adding vitamin B-6, which can reduce your homocysteine levels by about 20 percent — a significant amount.
The least common of the amino acids, methionine occurs in most protein-based foods but only in small amounts in legumes, peanuts, soybeans, and vegetables in general. Methionine levels are five to ten times lower in vegetables than in animal foods.