My favorite supplements
Why I like this supplement: N-acetylcysteine is the ultimate cold and flu fighter—even better than vitamin C. It has plenty of other impressive health benefits as well.
What it is: NAC is a sulfur-containing antioxidant and precursor to glutathione, the most powerful antioxidant made by the body. However, NAC is a potent antioxidant and immune booster in its own right. It's the treatment of choice in hospitals for acetaminophen (Tylenol) poisoning, and it's routinely used to break up mucus that collects in the lungs.
I first read about NAC in 1997 when Italian researchers published a placebo-controlled study showing that NAC suppressed flu (and likely cold) symptoms. When I tried it, I found that it consistently reduced my symptoms.
- Cold and flu fighter. The landmark 1997 NAC and flu study published in the European Respiratory Journal, involved 262 elderly patients who received 600 milligrams of NAC or placebos twice daily over the cold and flu season. Few of the subjects taking NAC developed flu symptoms, even though blood tests confirmed they were infected. Those who did develop symptoms suffered only mildly.
- Control of other infections. A study of AIDS patients found that high doses of NAC—several grams daily—significantly lengthened life expectancy. The researchers also noted that high blood levels of glutathione were better than immune-cell numbers in predicting survival (Proceedings of the National Academy of Sciences, 1997). Combined with the flu study, these findings point to NAC's ability to help fight a wide range of viral infections.
- Liver detox. In acetaminophen overdose, the liver's levels of glutathione are completely depleted, quickly leading to liver failure. NAC can help restore liver glutathione levels, and should be part of any liver detox program, at about only 500 milligrams daily.
- Polycystic ovary syndrome. About 10 percent of women of childbearing age have PCOS, a condition characterized by enlarged cystic ovaries, high levels of male hormones, infertility and prediabetic insulin resistance. A 2004 study in the International Journal of Gynecology and Obstetrics found that NAC supplements significantly reduced testosterone and insulin levels and improved glucose tolerance.
- Cocaine addiction. Several recent clinical studies have shown that high doses of NAC (1,200 to 3,600 milligrams daily) may help with behavioral disorders and cocaine addiction (Psychopharmacology, 2006, Journal of Clinical Psychiatry, 2004).
How to use NAC
Virtually all NAC supplements provide 500 milligrams per capsule. I take 500 milligrams daily, but double this amount during the cold and flu season.
When fighting a cold or flu, timing is critical. Ramp up the dosage at the first sign of symptoms. Take 1,000 milligrams to 2,000 milligrams to start, and repeat three or four times on the first and second day of the infection. If you wait until the second or third day to increase your NAC dosage, virus concentrations will have increased, and it will be difficult to suppress symptoms with any remedy. You can lower the dose after the third day unless symptoms persist.
Curious about NAC's chemical structure? The "acetyl" part comes from the fact that an L-cysteine molecule is bonded to a molecule called an "acetyl group," similar to the molecules that make up acetic acid, or vinegar. Acetylation increases absorption, stability and safety.
Tips for retailers
- High-quality NAC supplements will have a rotten-egg smell because of their high sulfur content.
- NAC is extraordinarily safe. Do not substitute pure L-cysteine, which can be neurotoxic in high doses.
Jack Challem is a personal nutrition coach in Tucson, Ariz., and the author of Stop Prediabetes Now (Wiley, 2007). E-mail him at [email protected] with NFM as a subject.
Natural Foods Merchandiser volume XXVIII/number 11/p. 39