Cysteine is an amino acid found in proteins. You can obtain cysteine through your diet, and your body can produce it from another amino acid called methionine. Cysteine can help protect your body from damage from free radicals and can help detoxify it. According to the University of Maryland Medical Center, a supplemental form of cysteine called N-acetyl-cysteine has a variety of medical uses, including treatment of lung problems. The best sources of dietary cysteine are high-protein foods.
Cysteine is essential to the production of glutathione, a powerful antioxidant that protects your cell membranes from free radical damage. This protection plays a part in everything from slowing the cosmetic and functional impact of aging to helping you fight off infections. In some cases, supplements can play a part in protecting you from heart disease, cancer, asthma and other health problems associated with free radicals.
So important is cysteine in detoxifying the body that N-acetyl-cysteine is used to treat acetaminophen poisoning. Glutathione, which is made by cysteine, plays a vital role in helping the liver detoxify harmful substances, and can chelate -- or attach to -- heavy metals such as lead, mercury and cadmium. According to the University of Maryland Medical Center, cysteine may also help improve symptoms associated with chronic bronchitis and chronic obstructive pulmonary disease.
In 2005, the National Academy of Sciences established a recommendation for cysteine intake, advising that everybody over 1 year of age take in 25 mg of combined cysteine and methionine for every gram of food protein. According to Immune Health Science, this works out to a recommended daily value of 575 mg for women and 700 mg for men.
Animal Sources of Cysteine
According to the University of Maryland Medical Center, meats and poultry are good sources of cysteine. The United States Department of Agriculture lists a cup of diced cooked turkey as containing .427 g of cysteine. The same amount of cooked chicken, with.486 g, ranks slightly higher. Milk, yogurt and cottage cheese are also good sources of cysteine.
Grain and Vegetable Sources of Cysteine
It is not necessary to eat animal products to get cysteine in your diet, but the amounts provided by grains and vegetables are more modest. The USDA lists a cup of cooked oats as containing .227 g, while a cup of fresh, sliced red bell peppers weighs in at .028 mg. Other good sources are Brussels sprouts, broccoli, and onions.
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