Not surprisingly there has been intense focus on our immune health over recent weeks; not just the steps we can take to protect ourselves against contracting the novel coronavirus, but also how we can improve our ability to fight it should we be unlucky enough to succumb. While rapid and important work is being done to develop immunotherapy and a Covid-19 vaccine, it’s important to note that we do not have a proven treatment yet. However, while we await an effective therapy, and indeed even when one arrives, one of the best things that we can be doing for our health and that of our loved ones in terms of prevention – in addition to the social distancing and hand sanitization measures already in place – is to improve our immune resilience. Unfortunately, it looks like we have a long battle ahead.
The immune system is the first line of defense against any infectious virus and consists of a complex collection of cells, processes, and chemicals that constantly defend our bodies against invading pathogens, including viruses, toxins and bacteria. Whilst much has been written about the importance of our basic everyday toolkit for supporting immune health – vitamins A, C, D, selenium, zinc and the like – many may not be aware of the importance of a semi-essential amino acid called N-Acetyl-L-Cysteine, or NAC.
One of NAC’s key functions in the body is to make the master antioxidant glutathione, arguably the most important antioxidant in the body and an essential nutrient for fighting cellular damage and optimizing immune health.
Chronic respiratory conditions
Because of its key role in the body, research on N-Acetyl-L-Cysteine has focused on a variety of therapeutic areas, not least among them respiratory health. Due to both its antioxidant and expectorant capabilities, NAC has been successfully investigated in patients suffering with a range of chronic respiratory conditions including COPD (chronic obstructive pulmonary disease)1-4, chronic bronchitis5-7, cystic fibrosis, asthma, pulmonary fibrosis and allergies8.
Influenza & pneumonia
NAC has also shown promise in the treatment of more acute conditions and infections such as influenza and pneumonia, particularly in the elderly. In a 6-month placebo-controlled clinical study, elderly subjects receiving 600mg NAC daily experienced significantly fewer influenza-like episodes and days in bed than did the placebo group. In addition, significantly fewer of the NAC group developed symptoms despite the rate of infection between both groups being the same.9
In another study, 1200mg NAC daily helped to reduce oxidative stress and its associated inflammatory lung damage in patients with community-acquired pneumonia, a condition most often caused by bacterial or viral infection.10
Mechanism of action
NAC helps to relieve symptoms by reducing inflammation and loosening mucous in the respiratory airways, thereby improving overall lung function. By thinning mucous and boosting glutathione levels, NAC may help to decrease the severity and frequency of wheezing, coughing and respiratory attacks in a number of conditions, and may be particularly useful in the elderly due to the fact that plasma cysteine and glutathione levels tend to decline with increasing age.
With regard to our current war against coronavirus and its associated complications, there is some hope that natural compounds such as NAC may be helpful in ameliorating the so-called “cytokine storm”, an extreme inflammatory response that can lead to acute respiratory distress, organ failure, and death. Research suggests that NAC among other compounds may help to reduce the inflammation in the lungs from RNA viruses and boost type 1 interferon response, thereby improving the body’s ability to create antibodies against these viruses. The researchers conclude that these compounds may indeed, “help provide relief to people infected with encapsulated RNA viruses such as influenza and coronavirus.” 11
Needless to say, further research in this area is warranted and would be greatly welcomed.
1. Pirabbasi E, Shahar S et al. Efficacy of Ascorbic Acid (Vitamin C) and/N-Acetylcysteine (NAC) Supplementation on nutritional and Antioxidant Status of Male Chronic Obstructive Disease (COPD) Patients. J Nutri Sci Vitaminol (Tokyo) 2016;62(1):54-61
2. PNR Dekhuijzen and WJC van Beurden. The role for N-acetylcysteine in the management of COPD. Int J Chron Obstruct Pulmon Dis. 2006 Jun; 1(2):99-106
3. Yanfei Shen, Wanru Cai, Shu Lei & Zhongheng Zhang. Effect of High/Low Dose N-Acetylcysteine on Chronic Obstructive Pulmonary Disease: A Systematic Review and Meta-analysis. COPD: J Chron Obstruct Pulmon Dis. vol 11 2014 Issue 3:351-358
4. Claudio M Sanguinetti. N-acetylcysteine in COPD: why, how, and when? Multidiscip Respir Med. 2016; 11:8
5. Grandjean EM, Berthet P et al. Efficacy of oral long-term N-acetylcysteine in chronic bronchopulmonary disease: a meta-analysis of published double-blind, placebo-controlled clinical trials. Clin Ther. 2000 Feb;22(2):209-21
6. Reichenberger F, Tamm M. N-acetylcystein in the therapy of chronic bronchitis. Pneumologies. 2002 Dec;56(12):793-7
7. C Stey, J Steurer et al. The effect of oral N-acetylcysteine in chronic bronchitis: a quantitative systematic review. European Respiratory Journal 2000 16:253-262
8. Tirouvanziam R, Conrad CK, Bottiglieri T et al. High-dose oral N-acetylcysteine, a glutathione prodrug, modulates inflammation in cystic fibrosis. Proc Natl Acad Sci USA. 2006 Mar 21; 103(12):4628-4633
9. De Flora S, Grassi C, Carati L. Attenuation of influenza-like symptomatology and improvement of cell-mediated immunity with long-term N-acetylcysteine treatment. Eur Respir J. 1997 Jul;10(7):1535-41
10. Quianwen Zhang, Yuanrong Ju et al. N-acetylcysteine improves oxidative stress and inflammatory response in patients with community acquired pneumonia. Medicine (Baltimore). 2018 Nov;97(45):e13087
11. DiNicolantonio JJ & McCarty MF. Nutraceuticals have potential for boosting the type 1 interferon response to RNA viruses including influenza and coronavirus. Progress in Cardiovascular Diseases. Available online 12 February 2020.