N-Acetyl Cysteine (NAC)
NAC is an antioxidant that increases intracellular glutathione at the cellular level. NAC can act as a precursor for glutathione synthesis as well as a stimulator of the cytosolic enzymes involved in glutathione regeneration. NAC is the more efficiently absorbed and used form of the amino acid L-cysteine. L-cysteine plays a role in the sulfation cycle, acting as a sulfur donor16 in phase II detoxification and as a methyl donor in the conversion of homocysteine to methionine.17,18 N-acetyl cysteine also enhances immune function.19-22 NAC attenuates the progression of the abnormal retention of lipids within liver cells by decreasing development of oxidative stress and subsequent increases in TNF-alpha.23 In addition, N-acetyl cysteine is used to support bronchial health.24-27
A metabolite of the sulfur-containing amino acid, Cysteine. Cysteine is found in high protein foods, N-Acetyl Cysteine is not. N-Acetyl Cysteine is produced within the human body. Cysteine plays a role in the sulfation cycle, acting as a sulfur donor in phase II detoxification and as a methyl donor in the conversion of homocysteine to methionine. Cysteine also helps synthesize glutathione, one of the body's most important natural antioxidants and detoxifiers. N-Acetyl-Cysteine is the acetylated form of L-Cysteine.
N-Acetyl Cysteine increases Glutathione Levels
N-Acetyl Cysteine is rapidly metabolized to intracellular glutathione. Glutathione acts as a powerful antioxidant in the body. Glutathione also detoxifies chemicals into less harmful compounds. N-Acetyl Cysteine also protects the body from acetaminophen toxicity and is used in hospitals for patients with acetaminophen poisoning. It has also been shown to be effective at treating liver failure from other causes as well.
N-Acetyl Cysteine Chelates Heavy Metals
Heavy metals like lead, mercury and arsenic are detoxified and removed from the body by N-Acetyl Cysteine . It also increases the excretion of zinc and other essential minerals when taken over an extended period. It is therefore necessary to supplement zinc, copper and other trace minerals when taking N-Acetyl Cysteine.
N-Acetyl Cysteine and the Immune System
Glutathione is known to aid in the transport of nutrients to lymphocytes and phagocytes, two major classes of immune cells, and to protect cell membranes. While purified glutathione is available as a dietary supplement, absorption is low, and N-Acetyl Cysteine is thought to be a better method of boosting cellular glutathione levels. N-Acetyl Cysteine is being investigated as a treatment for AIDS.
N-Acetyl Cysteine Breaks up Mucus
N-Acetyl Cysteine cleaves disulfide bonds by converting them to two sulfhydryl groups. This action results in the breakup of mucoproteins in lung mucus, reducing their chain lengths and thinning the mucus, improving conditions such as bronchitis and flu. Double-blind research has found that N-Acetyl Cysteine supplements improved symptoms and prevented recurrences in people with chronic bronchitis. N-Acetyl Cysteine at a dosage of 1,200 mg per day helps to prevent Influenza infection, reduces the symptoms of existing Influenza infection and reduces the duration of Influenza infections.
N-Acetyl Cysteine and Cancer
N-Acetyl Cysteine has been shown to reduce the proliferation of certain cells lining the colon and may reduce the risk of colon cancer in people with recurrent polyps in the colon. Its action as an antioxidant and a glutathione precursor may also contribute to a protective effect against cancer.
N-Acetyl Cysteine Cautions
When taking N-acetyl cysteine it is recommended that two to three times as much vitamin C be taken at the same time. Failure to do so may result in more harm than good from taking this product because of the prolonged presence of the oxidized form of L-Cysteine. The vitamin C also helps keep the glutathione that is produced from the Cysteine in its reduced form so that it can continue acting as an antioxidant.
N-Acetyl Cysteine Dosage
Typical dosage recommendations are in the range of 250-1500mg of NAC daily for the majority of therapeutic benefits.
N-Acetyl Cysteine Safety
NAC is considered safe for consumption in its therapeutic dosage ranges. Individual reactions may vary and anyone experiencing adverse symptoms while taking N-Acetyl Cysteine should discontinue it.
Other benefits:
It turns out that a little known dietary supplement may be your best defense against symptoms of the flu and common cold. The supplement, N-acetylcysteine (NAC), is a form of the amino acid cysteine and a component of protein. It's also one of the most potent immune boosters around.
Never heard of it? Virtually every hospital emergency room in the country stocks it as an antidote for acetaminophen (Tylenol®) poisoning. Overdoses of acetaminophen, a common analgesic drug, deplete your liver's supply of glutathione, a powerful antioxidant, leading to liver failure. Large supplemental doses of NAC restore liver glutathione levels and help the organ break down acetaminophen.
NAC has also been used since the 1960s as a "mucolytic" agent-that is, to break down lung-clogging mucous in chronic bronchitis and other respiratory disorders. Rich in what chemists call "free sulfhydryl groups," NAC breaks down the disfulfide bonds of mucous-in essence, thinning it out.
NAC Reduces Flu Symptoms
NAC has several key functions in the body. It is a precursor to glutathone, the principal antioxidant made in the body, meaning that NAC raises glutathione levels. Like other sulfur-containing nutrients, NAC is a powerful antioxidant. It also helps the liver break down hazardous compounds-that is, after all, part of the liver's job.
Unlike pure cysteine, which can be neurotoxic in high doses, NAC is completely safe. The "acetyl" part of the name comes from the fact that its cysteine is acetylated. That means it is bonded to a molecules called an "acetyl group." similar to the molecules that make up acetic acid, or vinegar. Acetylatation increases absorption, stability, and safety.
Researchers have for years studied NAC as a natural cancer-preventive compound. Glutathione levels are typically lower than normal in people with cancer and other serious diseases. Given NAC's ability to boost glutathione levels and to clear congested lungs, one of these researchers decided to test NAC on elderly men and women susceptible to flus and "flu-like" symptoms.
Silvio De Flora, M.D., of the Institute of Hygiene and Preventive Medicine at the University of Genoa, Italy, enrolled 262 subjects in a randomized, double-blind study to test the benefits of NAC. The subjects were given either two placeboes or two 600 mg NAC tablets daily for six months overlapping the wintertime flu season. All of the participants kept a daily log of their health and symptoms, and some were tested for flu antibodies.
While NAC did not prevent infection with flu germs, its effect was "striking," according to De Flora. Of the people with laboratory-confirmed flus who were taking NAC, only 25 percent developed symptoms. In contrast, 79 percent of the men and women taking placeboes developed clear-cut flu symptoms, according to De Flora's article in the European Respiratory Journal. In other words, NAC supplements reduced the likelihood of having flu symptoms by more than two-third.
Not everyone who gets sick during the winter, however, actually has the flu. So De Flora and his colleagues looked at more general flu-like symptoms, including fever, headache, achiness, nasal discharge, cough, and sore throat. Again, the differences between people taking NAC and placeboes was unmistakable. Month to month, over the flu and cold season, people taking NAC had anywhere from one-third to one-half the flu-like symptoms of those taking placeboes.
"An additional criterion for evaluating the severity of influenza-like episodes was the length of time in bed which, irrespective of the age of patients, was remarkably shorter in NAC-treated subjects," noted De Flora. "In fact, in the 10 subjects suffering from influenza-like episodes who were not bedridden, nine were under NAC treatment.
Overall, subjects taking NAC weathered their flu-like symptoms with greater ease. Most of the people taking NAC had mild flu-like symptoms, In contrast, a larger percentageof people suffered moderate and severe symptoms.
All of the subjects also underwent period immune function tests, in which antigens (noninfectious bacterial compounds) were applied to the skin. In healthy people, these antigens trigger a noticeable immune response, but the study's elderly subjects responded sluggishly when De Flora began his study. Retested after one, three, and six months , immune responsiveness-the ability to respond to an infection-improved steadily among people taking NAC, but not among those taking placeboes.
In concluding remarks, De Flora noted that NAC was not virus-specific and could provide "broad-spectrum protection" to ease or eliminate symptoms of infection, particularly in elderly and other people at risk for contracting the flu.
Increases Life Expectancy in AIDS
Further evidence of NAC's immune-enhancing properties comes from a study of patients infected with the human immunodeficiency virus (HIV), one of the most deadly viruses. Geneticists Lenora Herzenberg, Ph.D., Leonard Herzenberg, Ph.D., and their colleagues at Stanford University, determined that patients with HIV infections and acquired immune-deficiency syndrome (AIDS) had low levels of glutathione, and that declining of glutathione levels were a better indication of life expectancy than were a decrease in CD4 immune cells. CD4 T cells are the immune cells targeted and destroyed by HIV.
The Hertzenberg's followed 204 AIDS patients for three years. Those with normal glutathione levels in their CD4 cells generally outlived those with low glutathione levels. The Herzenberg's gave the AIDS patients either very large doses of NAC-3,200-8,000 mg-or a placebo daily for six weeks. Patients taking NAC had increased blood levels of glutathione.
After this phase of the study, The Herzenberg's offered NAC to all of the patients, and a majority took it for six months. Those who chose to take NAC supplements were "roughly twice as likely to survive for 2 years as the subjects who did not take NAC," explained Leonard Herzenberg.
Several years ago, researchers at the Gaslini Institute, Genoa, Italy, investigated how NAC enhances the immune response. Giovanni A. Rossi, M.D., and his colleagues studied NAC's effect on two types of immune cells, alverolar macrophages and polymorphonuclear leukocytes, obtained from human subjects. The macrophages were incubated by Staphylococcus aureus, a type of bacteria that causes strep throat and "flesh-eating bacteria" infections.
When Rossi added NAC to some of the cell cultures, the bacteria-killing properties of the macrophages and leukocytes increased significantly. Normally, these cells react so strongly to infections that many are killed in the process. With NAC, however, the enhanced germ-killing effect of macrophages and leukocytes did not result in greater self-destruction of these immune cells.
May Help Prevent Cancer
NAC has also shown promise as a "chemopreventive," or cancer-preventing, compound. Most cancers are caused by damage to deoxyribonucleic acid (DNA), which contains the genetic instructions for cell growth. Cancer-causing compounds attach to DNA via chemicals called "adducts." NAC decreases adduct numbers, according to an animal study published in Cancer Research.
Cancer cells also produce their own free radicals, which mutate DNA and signal other cancer cells to keep growing. A study, by Kaikobad Irani, Ph.D., found that antioxidants, particularly NAC, block these cell-growth signals and might inhibit the activity of some types of cancers. In the Journal of Cellular Biochemistry, the University of Genoa's De Flora wrote that NAC "appears to possess all four requirements necessary for a cancer chemopreventive agent to be used in humans: low cost; practicality of use (oral administration); efficacy, as documented by eperimental data; and tolerability and very low toxicity, well established in 30 years of clinical use."
NAC may also be of value in preserving muscle tissue in cancer patients, as well as people over overexercise. Wolf Droge, Ph.D., an immunologist at the German Cancer Research Center, Heidelberg, found that reasonably fit men had a "significant decrease" in muscle mass and an increase in body fat after eight weeks weightlifting. However, when the subjects took 600 mg of NAC three times weekly, their loss of body mass was almost completely prevented.
In sum, NAC is a power immune booster that can protect you against flu symptoms other infections and maybe even lower your risk of cancer. Furthermore, NAC supplements are extraordinarily safe, and recommended doses generally range from 500-1,200 mg daily. Because NAC contains sulfur, capsules have a strong smell. However, they generally do not cause stomach upset or bad breath.
Aids in treatment of Acute Liver Failure In Early Stages Of Disease
Acute liver failure occurs when cells in the liver die quickly, resulting in toxins being released into the bloodstream and brain. Patients often end up in a hepatic coma as a result of toxins not being cleared by the failing liver. Known causes of acute liver failure include autoimmune hepatitis, drug-induced liver injury, hepatitis A and B, and acetaminophen poisoning.
In a study published in the September issue of Gastroenterology, researchers found that acute liver failure patients in early stages of hepatic comas, when treated with the medicine N-acetylcysteine (NAC), were nearly 2.5 times more likely to survive than those treated only with a placebo.
"NAC is safe, easy to administer, doesn't require intensive care and can be given in community hospitals," said Dr. William M. Lee, professor of internal medicine at UT Southwestern and lead author of the study. "NAC is an excellent treatment for non-acetaminophen acute liver failure if the disease is caught early."
Acute liver failure affects about 2,000 people annually in the U.S., and 50 percent of those cases are caused by acetaminophen poisoning. Until this study, liver transplantation was the only treatment if the failure was from non-acetaminophen causes.
To test NAC's use in non-acetaminophen cases, researchers at 22 sites randomly assigned non-acetaminophen acute liver failure patients by the level of their coma, with those with mild to moderate coma in one group, and patients with more severe coma in the other group. Beginning in 1999 and continuing for eight years, 173 patients received either NAC or a placebo for 72 hours. Doctors recorded patient survival three weeks after they were placed on treatment.
Researchers found that 52 percent of acute liver failure patients in mild to moderate comas survived when treated with NAC, compared to just 30 percent of those treated with only a placebo. In patients experiencing more severe coma, treatment with NAC did not result in a significant difference in survival rates.
"That makes sense because patients with advanced comas typically die or get a transplant within a few days," said Dr. Lee, principal investigator of the Acute Liver Failure Study Group, a national consortium of liver centers formed in 1997 to increase research into the rare disease.
"This study establishes NAC as a treatment for non-acetaminophen acute liver failure patients in mild to moderate coma and provides the first glimmer of hope that something can help these direly ill patients," Dr. Lee said.
He said he will continue to study NAC as a therapy for acute liver failure not caused by acetaminophen poisoning to determine optimal dosing and duration.
Other UT Southwestern researchers involved in the study included Dr. Linda Hynan, professor of clinical sciences and psychiatry; Dr. Anne Larson, associate professor of internal medicine; and Dr. Joan Reisch, professor of clinical sciences and family and community medicine. Other Acute Liver Failure Group investigators involved in the study were from the University of California, Davis; the University of Michigan; Virginia Commonwealth University; University of California, San Francisco; Baylor University Medical Center; University of Nebraska; and the National Institute of Diabetes and Digestive and Kidney Diseases.
The study was funded in part by the National Institutes of Health, the Food and Drug Administration, and the Northwestern Medical Foundation. The N-acetylcysteine used was supplied by Apothecon/Geneva Pharmaceuticals, a division of Bristol Myers Squibb and Cumberland Pharmaceuticals.
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