L-Cysteine In Food

Cysteine (chemical formula C3H7NO2S), an amino acid that can be synthesized by the body or consumed in some nutrients is one. This amino acid plays an important role in maintaining protein structure. Cysteine is a sulfur amino acid and contains a sulfhydryl group. In the body, cysteine is synthesized from the aminoacid methionine. Cysteine is found in proteins along your body and plays a role in stabilizing proteins. Serves as a precursor for synthesis of proteins, taurine, glutathione, coenzyme A and inorganic sulfate.


High molybdenum and cobalt levels have been shown to alleviate the symptoms of excessive levels of these metals and may  be beneficial in other cases of heavy metal toxicity. According to research reported in the Journal of Nutrition in June 1987, sulfur-containing cysteine plays an significant role in neutralizing toxic trace minerals that are ingested.

The body uses cysteine to produce the antioxidant glutathione, as well as the aminoacid taurine. Cysteine along with 2 another amino acids form the antioxidant tripeptide glutathione. Glutathione is a molecule your body produces naturally by combining the 3 aminoacids cysteine, glycine and glutamine. Glutathione is a molecule that helps remove free radicals from your body. Is a important factor in detoxification and antioxidant mechanisms of your body. Many diseases are related to the deficiency of glutathione. Cancer, inflammation, AIDS, sickle cell anemia, heart attack, stroke,liver disease, Parkinson’s disease, Alzheimer’s disease correlate to glutathione deficiency.

N-Acetylcysteine (NAC) is a derivative of cysteine that can be taken in supplement form. NAC is then converted by the body into cysteine, which can then be transformed into another molecule, named glutathione. N-Acetylcysteine has been used successfully to treat glutathione deficiency in a wide range of infections, genetic defects and metabolic disorders, including HIV infection and COPD. According to a study reported in the June 2006 edition of the International Journal of Chronic Obstructive Pulmonary Disease, a 600 mg daily dose of NAC can be effective in the management of chronic obstructive pulmonary disease. Cysteine supports liver health and it helps to detoxify your body by binding to and eliminating harmful substances suchlike as those found in alcohol, drugs and other toxic compounds. Intravenous cysteine, (in the form of N-Acetylcysteine), decreases liver damage due to acetaminophen overdose in more than 99 percent of patients when administered in the first 12 hours, in a study reported in Hepatology, in April 2002.

Cysteine is a natural precursor to taurine, which is significant to build lean muscle mass. Therefore body builders often supplement cysteine to increase muscle growth and size. Cysteine, may be given intravenously to promote the production of proteins. This operation may help reduce the rate of protein breakdown and promote wound healing.

L-Cysteine In Food

Food sources include ricotta and cottage cheese, egg yolks, yogurt, meats including pork, poultry,  wheat germ, granola, oats, garlic and onions. The daily diet contributes approximately 1 gram of cysteine. Dietary deficiencies of other nutrients, such as methionine, vitamin B6 (Pyridoxine), vitamin B12, S-adenosyl-L-methioninee (SAMe), and folic acid may decrease body’s production of cysteine.


The common dose of L-cysteine supplements is between 250 and 1,500 mg daily. L-cysteine supplementation may be most useful when used in conjunction with vitamin B6, vitamin C, vitamin E and  and selenium. Avoid some forms of cysteine, as they are toxic; D-cystine, D-cysteine, and 5-methyl cysteine.

Side Effects

Some of the possible side effects include nausea, vomiting, diarrhea, and other gastrointestinal problems. High doses of cysteine may be toxic to human cells and may furthermore lead to death. Individuals with kidney stones particularly cystine stones, should avoid l-cysteine supplements. L-cysteine, could produce a false-positive result in the nitroprusside test for ketone bodies used in diabetes. Due to lack of long-term safety studies, supplementation should be avoided in nursing or pregnant women. Do not take l-cysteine supplements without consulting your doctor.

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