People often wonder what amino acid supplements are worth taking. Even though most Americans get plenty of protein in their diets, many individual amino acids (the components that make up protein) have impressive scientific research that indicates they’d be beneficial when added to a typical diet.
Among the best-researched amino acids is a form of cysteine, called n-acetylcysteine (often referred to as NAC). NAC is a more stable and bioavailable form of cysteine.
NAC was first developed as a therapeutic for its ability to break up mucus in the lungs in conditions like bronchitis. However, research into NAC’s other amazing benefits soon gained momentum. This was largely due to NAC’s ability to raise glutathione levels in the body, which is significant because glutathione is one of our body’s most important antioxidants. In recent years it has become apparent that NAC has great potential not only for raising our bodies antioxidant levels, but also for preventing heart disease, memory loss, cancer, and even aging itself.
Acetylcysteine converts to cysteine within the cell, acting as a precursor to glutathione and contributing to its regeneration. Unfortunately, cysteine is found in small amounts in the diet and much of this is in the form of cystine, which is less effective. Because of this it seemed logical that NAC would generate interest as an anticancer agent due to its ability to increase protective glutathione, and this has been shown to be true in many studies.
However, NAC’s most striking first role as an antioxidant was as an antidote to acetaminophen overdose. Acetaminophen is the common over-the-counter pain reliever that can cause severe liver damage in high doses, and NAC continues to be the best antidote to prevent this damage. Over many decades of research, however, NAC has grown from an antioxidant to a remarkable compound with many potential benefits. Much of this is very recent research, and scientific interest in NAC only continues to grow.
Many of us are concerned with mercury in our diets, and NAC has shown the ability to remove mercury from the body.1 Because of NAC’s initial use for lung congestion, researchers began investigating NAC as a protective antioxidant in smokers, and many studies have shown this to be true.2 NAC is being investigated in clinical trials to see if it prevents cancer in smokers. Also, NAC has been proven to improve impaired blood flow in smokers.3 But NAC’s heart benefits don’t end there, as NAC has been shown to increase nitric oxide production and lower homocysteine levels in humans.45 NAC even helps prevent damage from oxidized LDL cholesterol, especially when combined with green tea.6 This triple-action benefit of NAC on heart risk factors makes it very attractive as an addition to other cardiovascular health supplements.
NAC has also shown the ability to improve immune function and retard aging, especially in aging animals.7 Other studies have shown that aged animals can have dramatic improvements in immune function after NAC supplementation.8 And among the most exciting recent research are indications that NAC may be of benefit both for preventing and treating Alzheimer’s disease, due to its ability to lower the toxicity and production of beta-Amyloid protein (a suspected cause).910 Other research has shown NAC to be particularly effective at preventing damage from light within the eye 11, and studies are underway to evaluate NAC as a treatment for age-related vision loss. As if this list weren’t impressive already, NAC has shown the ability to help prevent the damage that comes with aging to mitochondria, our cells’ energy factories.12 This, along with NAC’s ability to prevent the toxicity of advanced glycation end-products (damaging molecules formed from glucose in the body) shows NAC to be a multi-faceted antioxidant protector with true anti-aging potential.13 NAC even prevents the toxic actions of homocysteine, which is implicated in brain and cardiovascular aging. 14, and prevents the damage caused by acrylamide, the carcinogen recently found in fried foods.15
With such an impressive list of attributes, NAC surely is at the top of the list of worthwhile supplements. Even scientists have commented that since NAC has a long history of human use and extremely low toxicity, it deserves more attention for its potential health benefits. Supplementing with NAC provides us not only a source of the important amino acid cysteine, but provides it in a stable form that has plenty of research-proven benefits. Give your dietary supplement program a big antioxidant boost with the amazing amino acid acetylcysteine … the grim reaper will hate you for it.
N-acetylcysteine has been shown to:
- break up mucus in the lungs in conditions like bronchitis
- raise our bodies’ antioxidant levels
- help prevent heart disease
- support memory
- prevent liver damage from acetaminophen toxicity
- remove mercury from the body
- improve impaired blood flow in smokers
- help prevent damage from oxidized LDL cholesterol
- improve immune function and retard aging
help protect against cancer
- Koh AS, Simmons-Willis TA, Pritchard JB, Grassl SM, Ballatori N. Identification of a mechanism by which the methylmercury antidotes N-acetylcysteine and dimercaptopropanesulfonate enhance urinary metal excretion: transport by the renal organic anion transporter-1. Mol Pharmacol 2002 Oct;62(4):921-6.
- Van Schooten FJ, Nia AB, De Flora S. Effects of oral administration of N-acetyl-L-cysteine: a multi-biomarker study in smokers. Cancer Epidemiol Biomarkers Prev 2002 Feb;11(2):167-75.
- Lu Q, Bjorkhem I, Xiu RJ, Henriksson P, Freyschuss A. N-acetylcysteine improves microcirculatory flow during smoking: new effects of an old drug with possible benefits for smokers. Clin Cardiol 2001 Jul;24(7):511-5.
- Anfossi G, Russo I, Massucco P, Mattiello L, Cavalot F, Trovati M. N-acetyl-L-cysteine exerts direct anti-aggregating effect on human platelets. Eur J Clin Invest 2001 May;31(5):452-61. Andrews NP, Prasad A, Quyyumi AA. N-acetylcysteine improves coronary and peripheral vascular function. J Am Coll Cardiol2001 Jan;37(1):117-23.
- Roes EM, Raijmakers MT, Peters WH, Steegers EA. Effects of oral N-acetylcysteine on plasma homocysteine and whole blood glutathione levels in healthy, non-pregnant women. Clin Chem Lab Med 2002 May;40(5):496-8.
- Locher R, Emmanuele L, Suter PM, Vetter W, Barton M. Green tea polyphenols inhibit human vascular smooth muscle cell proliferation stimulated by native low-density lipoprotein. Eur J Pharmacol 2002 Jan 2;434(1-2):1-7. Viora M, Quaranta MG, Straface E, Vari R, Masella R, Malorni W. Watanabe T, Pakala R, Katagiri T, Benedict CR. Antioxidant N-acetylcysteine inhibits vasoactive agents-potentiated mitogenic effect of mildly oxidized LDL on vascular smooth muscle cells. Hypertens Res 2002 Mar;25(2):311-5.
- Puerto M, Guayerbas N, Vi;ctor V, De la Fuente M. Effects of N-acetylcysteine on macrophage and lymphocyte functions in a mouse model of premature ageing. Pharmacol Biochem Behav 2002 Nov;73(4):797.
- De La Fuente M, Miquel J, Catalan MP, Victor VM, Guayerbas N. The amount of thiolic antioxidant ingestion needed to improve several immune functions is higher in aged than in adult mice.Free Radic Res 2002 Feb;36(2):119-26.
- de Ceballos ML, Brera B, Fernandez-Tome MP. beta-Amyloid-induced cytotoxicity, peroxide generation and blockade of glutamate uptake in cultured astrocytes. Clin Chem Lab Med 2001 Apr;39(4):317-8.
- Studer R, Baysang G, Brack C. N-Acetyl-L-Cystein downregulates beta-amyloid precursor protein gene transcription in human neuroblastoma cells. Biogerontology 2001;2(1):55-60.
- Seko Y, Pang J, Tokoro T, Ichinose S, Mochizuki M. Blue light-induced apoptosis in cultured retinal pigment epithelium cells of the rat. Graefes Arch Clin Exp Ophthalmol 2001 Jan;239(1):47-52. Tanito M, Nishiyama A, Tanaka T, Masutani H, Nakamura H, Yodoi J, Ohira A. Change of redox status and modulation by thiol replenishment in retinal photooxidative damage. Invest Ophthalmol Vis Sci 2002 Jul;43(7):2392-400.
- Miquel J. Can antioxidant diet supplementation protect against age-related mitochondrial damage? Ann N Y Acad Sci 2002 Apr;959:508-16. Xu D, Finkel T. A role for mitochondria as potential regulators of cellular life span. Biochem Biophys Res Commun 2002 Jun 7;294(2):245-8.
- Yamagishi S, Inagaki Y, Okamoto T, Amano S, Koga K, Takeuchi M, Makita Z. Advanced glycation end product-induced apoptosis and overexpression of vascular endothelial growth factor and monocyte chemoattractant protein-1 in human-cultured mesangial cells. J Biol Chem 2002 Jun 7;277(23):20309-15.
- Ho PI, Collins SC, Dhitavat S, Ortiz D, Ashline D, Rogers E, Shea TB. Homocysteine potentiates beta-amyloid neurotoxicity: role of oxidative stress. J Neurochem 2001 Jul;78(2):249-53.
- Park J, Kamendulis LM, Friedman MA, Klaunig JE. Acrylamide-induced cellular transformation. Toxicol Sci 2002 Feb;65(2):177-83.