N-Acetylcysteine also know as N-Acetyl Cysteine or NAC is a version of the amino acid L-Cysteine. It is a powerful antioxidant and a premier antitoxin and immune support substance. Antioxidants neutralize free radicals, which are produced by normal metabolic activity. When free radicals are left unchecked they cause damage to cells and DNA and are considered by scientists to be a major factor in the cancer and aging processes.
The principal value of NAC covered here is as a nutritional supplement to help the liver created a substance called glutathione. Both Cysteine and Methionine are good precursors of glutathione, but NAC is better. L-Cysteine loses approximately 85% of its sulfur group (which becomes the active part of glutathione) in the digestion process, while NAC, a more stable compound, loses only 15%. This means that NAC has almost six times more effective sulfur groups left after digestion.
It is preferable to purchase amino acids from a source where you know they are fresh and have not been on the shelves for a long time.
Glutathione is a tri-peptide composed of three amino acids: Cysteine, Glutamic Acid and Glycine. Glutathione and the enzymes it forms, such as Glutathione peroxidase, are essential to all life and are found in tissues of virtually all plants and animals. Glutathione peroxidase is one of the body's most important naturally occurring antioxidants.
Glutathione is present in all human cells, with the highest levels found in the liver, lung, lens of the eye, pancreas, spleen and kidneys. Since glutathione is such an vital naturally occurring antioxidant, NAC is now considered a potent protective agent in many diseases and conditions in which reactive oxygen molecules (free radicals) play a role.
Glutathione is a key protector against all types of pollution. Glutathione protects against cellular peroxidation caused by exposure to pesticides, toxic herbicides like paraquat, plastics, benzene and carbon tetrachloride. It also protects against the toxic effects of heavy metals, cigarette smoke, smog, drugs like Tylenol (acetominophen), solvents, dyes, phenols and nitrates, and the side-effects of anti-cancer drugs like cyclophosphamide and adriamycin.
Glutathione works to inhibit the formation of free radicals, dangerous agents that suppress the immune system and promote the formation of mutagens and carcinogens. Free radicals also speed up the aging process, and it is due to this antioxidant activity that Glutathione is considered useful in the prevention and treatment of a wide range of degenerative diseases. Supplemental N-Acetyl Cysteine may exert its anti-aging effect by increasing glutathione levels.
Studies at the Louisville School of Medicine have shown that Glutathione possesses a unique ability to slow the aging process. While Glutathione aids in the protection of all cells and membranes, a study at Harvard Medical School found that glutathione is especially able to enhance immune system cells, protecting against damage from radiation and helping to reduce the side effects of chemotherapy, x-rays, and alcohol. As a detoxifier of metals and drugs, glutathione also aids in the treatment of blood and liver disorders.
The discovery that NAC (and the glutathione formation it promotes) is an effective antidote for acetaminophen poisoning first indicated NAC's importance as an antioxidant. Acetaminophen is a commonly used pain reliever that until recently was considered safe in small commonly used doses. Now new research tends to cast a doubt that the drug is completely safe at any dosage level. Acetaminophen is the main ingedient in many over-the-counter drugs both branded and generic - the principal brand being Tylenol. There is some disagreement about the safety of acetaminophen in small doses so consider that the jury is still out.
We do know that ingestion of 10-15 grams of acetaminophen in a single dose can result in liver damage or failure and death 2-5 days later unless NAC is given to the patient within within 12 hours of the acetaminophen ingestion. NAC is not effective if given later than 12-16 hours since the although the glutathione can prevent oxidant-derived cellular damage, it cannot reverse cell death that has already occurred.
Generally we recommend not using acetaminophen if something else is readily available. Since NAC and acetaminophen cancel the effects of each other the use of acetaminophen will limit any benefits you might expect from your use of NAC. Adversely, if you must take acetaminophen for some reason it would be very wise to also take NAC in an attempt to prevent possible liver or/and kidney damage.
NAC is also itself an antioxidant with the capacity to scavenge hydrogen peroxide, hypochlorous acid, and the hydroxyl radical but most of its antioxidant value however, is due to its promotion of glutathione formation. This activity of NAC protects membranes from damage by superoxide radical systems, and also protects human bronchial fibroblasts from damage by tobacco smoke. NAC is receiving growing interest from both scientists and physicians, due to the enormous role that oxidation and free-radical mediated damage play in so many diseases.
NAC is an excellent mucolytic agent. It keeps the membranes of the respiratory system moist, thereby lessening the irritation of dry air, dust, and pollutants. It has been used as a treatment for bronchitis for over 30 years and it is useful in most respiratory disorders and diseases.
Research in the area of immunology has found NAC to significantly enhance human T-cell function, especially in older individuals. The study of HIV and AIDS has contributed greatly to the understanding of the potential roles of cysteine and its precursor NAC in immune function. Cysteine and glutathione levels are significantly depressed in people with HIV infection and AIDS.(22) In fact, this depletion of cysteine and glutathione has been observed in most patients at all stages of the disease. Some researchers feel that glutathione deficiency plays a major role in the pathogenesis of HIV and AIDS.
NAC is currently being studied in clinical trials as an enhancer of immune function in people with AIDS where It has shown the ability to restore cysteine and glutathione levels and slow replication of HIV. Many feel that NAC's greatest potential in this area is its possible ability to prevent the progression of asymptomatic HIV-infection to AIDS.
Another promising area of research is NAC's and glutathione's potential roles in cancer prevention. A number of studies have documented antimutagenic effects of NAC against a wide variety of mutagens and NAC has shown anticarcinogenic effects in various rodent organs, including mammary glands, skin, trachea, lung, bladder, and colon. Because of this animal research, NAC may be one of the most promising nutrients ever tested. NAC is currently being studied in clinical trials in both the U.S. and Europe for the prevention of second primary tumors in patients who have been previously treated for cancer.
The antimutagenic and anticarcinogenic mechanisms of NAC's are multiple. First, it directly detoxifies reactive oxygen mutagens such as superoxide, hydrogen peroxide, and singlet oxygen and also inhibits environmental carcinogens such as cigarette smoke condensate, and aflatoxin. Within cells, NAC is rapidly converted to cysteine and then to glutathione which detoxifies carcinogens inside cells and helps decreases carcinogen induced DNA damage. In its role as an inhibitor of DNA adduct formation in various organs and tissues, NAC and glutathione may prove potent protectors not only against cancer, but a wide variety of diseases.
Toxic metals can accumulate in the body over time from many sources such as drinking water, foods, and possibly even from tooth fillings made of silver-mercury amalgam. NAC may function as a chelator of heavy metals. In other words, NAC binds to toxic heavy metals such as mercury and lead, and helps to remove them from the body. Most chelating agents, such as EDTA, must be given intravenously. NAC is one of the most effective oral chelating agents. Taken regularly over a period of time, NAC will help remove many toxic heavy metals from the body. This is of course a slow process.
NAC is one of the most underrated supplements on the sports nutrition market. Numerous studies lend credibility to its potent bodybuilding potential. Exercise and weight training have been shown to generate large amounts of catabolic free radicals. These free radicals may damage muscle tissue. NAC supplementation increases blood serum glutathione levels and it is believed that this is responsible for many of the positive influences NAC has on preserving and increasing lean body mass.
NAC is currently the dietary supplement of choice for boosting or conserving the body's stores of glutathione, cysteine, and other sulfhydryl antioxidants. NAC is a much better source of glutathione than taking glutathione itself, because less than half of supplemental glutathione is absorbed from the digestive system. This greater efficiency is important since cellular glutathione levels tend to drop 30% to 35% with age.
NAC is easily absorbed through oral administration, with blood peaking within an hour. NAC is metabolized in the gut wall and liver and converted to L-cysteine, and ultimately, from cysteine into glutathione. Oral NAC has been shown to increase glutathione levels in numerous different tissues of the body in both animals and humans.
While NAC is a more stable compound than oral cysteine, as it is metabolized, some NAC may be oxidized and become insoluble. This may lead to the formation of kidney stones. It is therefore recommended that persons taking NAC take at least as much vitamin C as NAC. Diabetics should consult their physician before using NAC, since it may have an insulin-blocking effect.
NAC has typically been utilized at dosages from 200 mg to 1200mg per day. Higher doses have been utilized in more severe disease states, but for general use as an antioxidant, most would want to consume from 200 mg to 600 mg daily. People exposed to large sources of oxidants and glutathione depleters, such as smokers or drinkers would probably want to use NAC at the upper level of this range. For other uses, such as in HIV infection and severe lung conditions NAC should be used under a physician's care. This is not due to NAC-associated toxicity, as none has been reported, but self-medication of serious conditions is never wise.
Recent studies indicate that vitamin E and selenium also play a role in the metabolism and regeneration of glutathione and may work synergistically to enhance NAC's properties.
NAC is available as a prescription drug for this purpose of being used as a mucolytic agent for loosening lung secretions. when used this way it is often used as a nebulized mist. It can also be bought across the counter in health food stores in capsules etc; for far less money.
Typical supplemental doses of NAC or cysteine is 5OO-15OO mg. per day.
