GENERAL DESCRIPTION:
Cysteine is a non-essential amino acid that
can be manufactured in the liver. It is obtained in the diet from beans, brewer’s yeast,
broccoli, Brussels sprouts, dairy products, eggs, fish,
garlic, legumes, meat, nuts, onions, red peppers, seafood,
seeds, soy, whey, and whole grains. N-acetyl cysteine
(NAC) is a modified form of cysteine. NAC helps the body make the antioxidant enzyme glutathione.
ROLE FOR ANTI-AGING:
Cysteine may help to diminish the effects of
aging, protect against heart disease and
cancer, boost the immune system, promotes metabolism of fats and production of muscle tissue,
aid healing after surgery, promote hair growth, and prevent
hair loss. It is also known to work
synergistically with vitamin E and selenium as an
antioxidant, protecting against the
damaging effects of radiation, acetaldehyde, acrolein in
tobacco smoke, alcohol and environmental
pollutants.
Several studies have found that NAC is beneficial
to patients with chronic bronchitis and
angina; there is also preliminary
evidence to suggest that it may help to prevent colon cancer Some
experts believe that NAC increases the efficacy of
chemotherapy drugs and helps to alleviate their side
effects, however there is little clinical evidence to
support this. Very high doses of NAC are given to patients in hospital to treat acetaminophen poisoning.
DEFICIENCY SYMPTOMS:
Symptoms of cysteine deficiency include: apathy, loss of pigmentation in hair, edema, lethargy, liver damage, muscle loss, skin lesions,
weakness, fat loss, and slowed growth in
children.
THERAPEUTIC DAILY AMOUNT:
Optimal levels of NAC and cysteine have not
been determined. 250 to 1,500 mg of NAC per day has been used in clinical studies with no adverse
effects.
MAXIMUM SAFE LEVEL:
established -there are no known signs of toxicity from
cysteine. NAC appears to be a very safe
supplement even in high doses, however an animal study
found that 60-100 times the normal dose could cause liver injury. Note: NAC is known to have antioxidant activity, however one study found
that daily doses of 1.2g or more increased oxidative
stress.
SIDE EFFECTS/CONTRAINDICATIONS:
People with diabetes mellitus and allergies to
eggs, milk, or wheat should not take supplementary
cysteine. People taking the drug may
experience severe headaches when taking NAC. Cysteine
supplements must be taken with vitamin C to prevent cysteine
being converted to cystine, which may form kidney or bladder stones. People with kidney or liver
disease should consult their doctor before taking
supplementary cysteine.
