For more than three decades, a safe, low-cost compound has provided millions of people relief from the coughing, wheezing, and thick phlegm associated with cold and flu. Of course, pharmaceutical companies long ago co-opted it for profit by incorporating it into various patented drugs.
The sad consequence is that most aging individuals have never heard of it. Even many doctors remain unaware of its potential role as a frontline defense against some of today’s most deadly public health threats, including:
- Acetaminophen toxicity and acute liver failure: the number one cause of acute liver failure in the United States.1
- Influenza: whose victims are primarily aging individuals—three quarters of all flu-related deaths occur in the elderly.2
- Chronic obstructive pulmonary disease: the fourth-leading cause of death in the United States (includes emphysema and chronic bronchitis).2
- Helicobacter pylori: the bacterial culprit behind stomach ulcers, and a potentially lethal pathogen closely linked to malignant gastric cancer, the second most frequent cause of cancer death worldwide.3
Fortunately, renewed clinical interest in its broad-spectrum benefits is yielding fresh data on promising interventions for this safe, effective compound.
In this article, you will discover the latest research on N-acetyl cysteine (NAC), a readily available, inexpensive amino-acid derivative with four decades of scientific validation. You will learn of its role in restoring intracellular levels of one of the body’s most powerful antioxidant defenses, glutathione (GSH). You will also find out how 600-1,800 mg of NAC daily may act as an effective intervention against a constellation of chronic, degenerative diseases, including impaired glucose control and cancer.
An Underutilized Intervention
NAC is a slightly modified version of the sulfur-containing amino acid cysteine. When taken internally, NAC replenishes intracellular levels of the natural antioxidant glutathione (GSH), helping to restore cells’ ability to fight damage from reactive oxygen species (ROS).
NAC has been used in conventional medicine for more than 30 years, primarily as a mucolytic (mucous-thinner) inhaled to manage conditions such as cystic fibrosis, in which mucous is abnormally thick and tenacious. While there is little in the scientific literature to support its use as an inhalant, NAC administered in this form remains highly popular among experienced pulmonary speclialists.4,5
NAC given intravenously or orally, on the other hand, saves lives every year as a treatment for acute poisoning with acetaminophen-containing pain-relieving drugs. Acetaminophen is sold as Tylenol® and combined with other drugs to create analgesic compounds, including Vicodin® and Percocet®.6 Overdoses with acetaminophen are the number one cause of acute liver failure in the United States.6-8 Too much acetaminophen overwhelms the body’s glutathione reserves, which creates widespread and irreversible liver damage. NAC quickly restores protective levels of glutathione, averting catastrophe.7
Beyond this particular application, NAC has remained a relatively obscure and poorly understood compound until quite recently. Scientists all over the world are now beginning to understand just how vital glutathione metabolism really is, and how many disease states involve glutathione deficiency.9 According to Stanford University’s Dr. Kondala R. Atkuri, “NAC has been used successfully to treat glutathione deficiency in a wide range of infections, genetic defects and metabolic disorders, including HIV infection and COPD. Over two-thirds of 46 placebo-controlled clinical trials with orally administered NAC have indicated beneficial effects of NAC measured either as trial endpoints or as general measures of improvement in quality of life and well-being of the patients.”9
Multitargeted Regulation of Gene Expression
Much of NAC’s beneficial activity derives from its capacity to modulate expression of genes for myriad signaling molecules in the inflammatory response.10-12 NAC inhibits expression of pro-inflammatory cytokines following exposure to bacterial cell components and infection with influenza A virus.13,14 NAC suppresses the “master signaling molecule” nuclear factor-kappaB (NF-kB), which in turn prevents activation of multiple inflammatory mediators.15,16 NAC also regulates the gene for COX-2, the enzyme that produces pain- and inflammation-inducing prostaglandins in a wide array of chronic conditions.17
NAC’s ability to replenish the intracellular glutathione supply and mitigate oxidative damage is a separate and equally powerful mechanism that affords protection against DNA damage and cancer development, even in smokers.18 NAC’s inhibition of inflammatory cytokine production is another mechanism credited with cancer reduction in various body tissues.19
Gene expression modifications induced by NAC may also help reduce the acute oxidant-provoked inflammatory response following exercise, making vigorous activity safer and even more beneficial.20 Finally, obesity-associated insulin resistance, which arises from production of inflammatory signaling molecules in fat cells, can be sharply mitigated by NAC through regulation of their genes.21,22
The recent explosion of scientific evidence for NAC’s multi-targeted health benefits is matched only by the willful ignorance of the mainstream medical community. Some even question its safety, despite nearly 40 years of use in a variety of clinical conditions, which have established the safety of this compound, even at very high doses and for long-term treatments.18 One study demonstrated the safety of 1,800 mg per day for 142 days, while another study demonstrated the safety of 2,800 mg per day for 3 months.23
Here is a selection of the most compelling information about NAC from the global scientific community—information that should convince even skeptical mainstream physicians.
Potent Influenza Protection
H5N1 influenza, or bird flu, is a lethal and potentially pandemic infection that produces the massive release of inflammatory mediators aptly called the “cytokine storm.”24 Other more common forms of influenza also act by triggering massive cytokine releases that inflame vulnerable lung tissue. In early 2010, it was discovered that NAC offers dual protection against bird flu. It inhibits both virus replication and expression of pro-inflammatory molecules in cells infected with H5N1 virus, holding out the promise of effective protection in the event of a global avian flu pandemic.13
NAC has also proven effective against seasonal influenza and flu-like illnesses. In a large study of older adults who took 600 mg twice daily for 6 months, only 25% of those experienced influenza-like episodes, compared with 79% in the placebo group.25 Even those with flu symptoms experienced a significant reduction in illness severity and length of time confined to bed. All subjects tolerated the treatment well. The study’s lead author, Dr. Silvio de Flora, commented that “Administration of N-acetyl cysteine during the winter, thus, appears to provide a significant attenuation of influenza and influenza-like episodes, especially in elderly high-risk individuals.”25
Influenza is a complex disease with multiple targets, most notably inflicting damage to lung tissue through extreme oxidative stress and inducing genes for a large variety of inflammatory mediators.26,27 At the microscopic level the destruction is vivid. The influenza virus causes such intracellular turmoil that the term “cell boiling” has been used to describe the devastation.28 But pretreatment of cells with NAC significantly offsets these effects, reducing the oxidative and inflammatory burden within lung tissue through multiple mechanisms.26,28-30
NAC has now been shown to protect laboratory mice from lethal influenza infection, synergistically enhancing the effects of several common antiviral medications.31,32 And a nutrient mixture containing NAC, green tea extract, certain amino acids and micronutrients had powerful antiviral effects in cultured cells, rivaling those of prescription flu drugs such as amantadine and oseltamivir (Tamiflu®).33,34 The NAC-based mixture actually affected viral replication for a longer period than did the drugs.34
In the words of prolific medical theorist Mark F. McCarty, “The most foolproof way to promote survival in epidemics of potentially lethal influenza is to target… intracellular signaling pathways which promote viral propagation or lung inflammation.”30 McCarty goes on to cite NAC’s benefits as a multitargeted supplement with precisely those attributes. NAC at doses of 600 mg twice daily may significantly reduce the risk of a devastating bout of influenza.