NAC is a nutritional supplement that is an excellent source of sulfhydryl groups and plays both direct and indirect antioxidant action in the body. NAC is popular because it has been shown to maintain the availability of cysteine that is known to be the rate-limiting substrate for glutathione synthesis.

N-acetyl L-cysteine is a precursor of L-cysteine that elevates glutathione biosynthesis. NAC is an acetylated derivative of amino acid cysteine. NAC has a chemical structure, formed by the sulfhydryl functional group (-SH) plus an acetyl group (-COCH₃) linked to an amino group (NH₂).

 

ZENITH NUTRITION NAC  

Zenith Nutrition N-Acetyl L-Cysteine is a highly bioavailable nutritional supplement that is an excellent source of sulfhydryl groups. The vegetarian dietary supplement is manufactured in a GMP-certified facility and has gone through strict quality control to validate its purity and potency. Every serving of the capsule provides 500mg of NAC which is more bioavailable in the body than regular cysteine. The supplement is suitable for both men and women and does not contain sugar, corn, soy, dairy, yeast, gluten.

 

IS IT A SAFE SUPPLEMENT?    

N-Acetyl L-Cysteine (NAC) is a safe, well-established supplement approved by Food and Drug Administration (FDA). NAC has very low toxicity, has been found to be a promising, relatively low-risk intervention.

 

WHY SHOULD WE SUPPLEMENT WITH NAC?

N-acetyl L-cysteine (NAC) is not found in natural sources, although cysteine is found in meat, fish, garlic, grains, dairy, soybean, and eggs. N-acetyl L-cysteine is a derivative of the natural amino acid cysteine that is obtained when an acetyl group is attached to the nitrogen molecule of cysteine. The regular active form of cysteine has low intestinal absorption, poor water solubility, and rapid hepatic metabolism. NAC supplements provide acetyl radicals linked to amine, which eliminates these disadvantages. The acetyl group in NAC makes cysteine more water-soluble, functions to speed absorption and distribution of cysteine. NAC supplements are the most convenient way to obtain amino acid cysteine, the acetyl group reduces the reactivity of the thiol (-SH), making NAC less toxic and less susceptible to oxidation than cysteine.

 

HOW DOES NAC SUPPLEMENT SERVE FOR GLUTATHIONE SYNTHESIS?

NAC gets deacetylated in the intestine and liver to release cysteine as one of its metabolites. Cellular levels of glutamic acid and glycine are plentiful. The availability of amino acid cysteine functions as a major factor in the regulation of glutathione production. Glutathione functions for resisting oxidative stress with the enzyme glutathione reductase (GR), recycling oxidized glutathione back to the reduced form. NAC supplements increase GSH levels by providing the liver with an increased supply of cysteine.

 

NAC IS A POWERFUL ANTIOXIDANT    

Intracellular oxidative stress occurs when reactive oxygen species and nitrogen species are produced beyond the cell’s natural scavenging mechanisms. Hyperproduction of oxygen free radicals can overwhelm the body and deplete the natural antioxidant stores, the free radicals have been implicated as contributors to cell, tissue, or organ damage. The critical antioxidant power of NAC is directly linked to its ability to increase levels of intracellular cysteine with a subsequent increase in glutathione (GSH). The cysteine component of NAC combines with glutamate and glycine, all of which are precursors in the production of glutathione (cysteine is a rate-limiting precursor to glutathione). NAC reacts with hydroxyl radical (-OH), nitrogen dioxide (-NO₂), carbon trioxide ion (CO₃^•), and thiyl radical (RS^•), in addition to the nitroxyl (HNO) that is the reduced and protonated form of nitric oxide (^•NO). NAC maintains adequate glutathione levels (the body’s major antioxidant) in the intracellular environment. Glutathione serves a central role in protecting against internal toxic agents (such as cellular aerobic respiration and metabolism of phagocytes) and external agents (such as NO, sulphur oxide and other components of cigarette smoke, and pollution).

 

NAC PROMOTES OPTIMAL IMMUNE FUNCTION

Our immune system constantly defends our body against pathogens, compromised immunity is an important reason to acquire an infection. Supplementing with a super antioxidant like NAC optimizes the immune health by maintaining optimal glutathione status, the master antioxidant in the body. In older individuals or immune-compromised individuals, reactive oxygen species is increased due to decreased glutathione, which causes dysregulation of immune responses. Low glutathione levels in the body hamper cellular immunity which is required for the host to fight viral infections. NAC acts as a precursor to glutathione by supplying cysteine which boosts the production of glutathione, increases CD4+ T cell numbers. NAC can change the redox balance towards reduced status inside neutrophils by replenishing reduced glutathione, which suppresses NG-kB activation.

 

NAC BOOSTS FERTILITY

Studies have demonstrated that infertile men have higher levels of semen reactive oxygen species (ROS) than fertile men. In infertile men’s semen, leukocytes, immature or abnormal spermatozoa are the main sources of reactive oxygen species. Higher levels of semen ROS and reduced semen antioxidant capacity can cause sperm dysfunction, sperm DNA damage, and reduced male reproductive potential. Dietary NAC supplementation may have a positive effect on sperm parameters. NAC has been found to improve sperm quality, level of oxidative stress in infertile men. NAC may also improve fertility in women suffering from polycystic ovary syndrome (PCOS) by augmenting ovulation, embryo quality, and reversing weight gain.

 

NAC PREVENTS SMOKING-RELATED LUNG DAMAGE

Tobacco smoking is a highly prevalent, key public health concern. Exposure to tobacco smoke induces oxidative stress, inflammation and decreases antioxidant expression. Studies have found that NAC supplementation prevented the loss of pulmonary GSH and abolished the effects of cigarette smoke. NAC helps reduce H₂O₂‐induced damage to epithelial cells and NF-kB activation in some cells. Research studies have found the smoking-induced abnormalities in polymorphonuclear neutrophils, fibroblasts, and epithelial cells. NAC with its antioxidant properties increases glutathione and modulates glutamatergic, mitochondrial, and inflammatory pathways. There is research evidence to suggest that NAC is efficacious for reducing the number of cigarettes smoked, improve mucociliary transport and prevent oxidative damage to the lungs.

 

NAC PROMOTES LIVER DETOXIFICATION

In conditions like illness, medications, aging, immune challenges, or unhealthy lifestyle, our natural body’s detox system has considerable overlap with the antioxidant defense. Experimental studies show that NAC best sustains the body’s glutathione stores. With its free thiol, NAC binds to active redox metal ions, such as the ones from transition metals, copper (Cu²⁺) and iron (Fe³⁺), heavy metals, cadmium (Cd²⁺), mercury (Hg²⁺), and lead (Pb²⁺), forming complexes that are easily excreted by the body. NAC supports a diverse collection of detox enzymes that support effective detoxification. NAC is widely accepted as a safe and effective supplement for paracetamol poisoning. Paracetamol over dosage involves toxic effects on the liver due to the excessive production of N-acetyl-p-benzoquinone imine (NAPBQI), which is a hepatoxic metabolite that under normal conditions is easily inactivated by liver glutathione. In case of intoxication, glutathione is depleted and NAPQI accumulates in the liver causing liver damage. The function of NAC is to replenish glutathione levels and contribute to a great supply of oxygen to the liver.

 

NAC HELPS WITH RESPIRATORY CONDITIONS

NAC exhibits direct as well indirect antioxidant properties. Its direct antioxidant effects come from its thiol group interacting with and scavenging reactive oxygen species, while the indirect antioxidant effect is related to its role as glutathione (GSH) precursor, resulting in an increase of intracellular GSH concentration. NAC has mucolytic properties of degrading the disulfide bonds (S-S) to a sulfhydryl bond (-SH) in mucoprotein complexes. NAC decreases the severity and frequency of wheezing, coughing, relieves respiratory ailments by reducing inflammation and loosening mucous in the respiratory airways, thereby improving overall lung function. NAC prevents bacterial stimulation of mucin production and mucus hyper-secretion and facilitates the removal of pulmonary secretions.

 

NAC HELPS ATTENUATE MUSCLE FATIGUE

Strenuous exercise consisting of muscle contractions can result in muscular fatigue associated with the development of oxidative stress in humans. Acute muscular fatigue increases oxidative stress, circulating levels of hydroxyl radicals, lactate dehydrogenase and creatine kinase, markers of protein breakdown. NAC is a major contributor to the maintenance of cellular glutathione status in muscle cells and thus prevents muscle fatigue. Studies have demonstrated that NAC supplementation can help inhibit such biochemical changes caused by free radicals and inhibit loss of mechanical function during fatigue. NAC improves skeletal muscle antioxidant capacity through thiol compounds, including superoxide dismutase, glutathione peroxidase, catalase, and glutathione, thereby proves beneficial for muscle performance.

 

NAC BENEFITS BRAIN FUNCTION

The human brain is particularly vulnerable to oxidative stress as it uses a lot of oxygen. Supplementing with NAC increases levels of glutathione in the brain, supports healthy neurotransmission through detox and antioxidant activities. As a potent antioxidant, NAC has been shown to neutralize free radicals which are found to be key players in brain function decline. Tackling with oxidative imbalance helps reduce the impairments in neurological functions, increases levels of glutathione in the brain, and supports neurotransmitters through its detox, antioxidant and anti-inflammatory activities. As a potent antioxidant, NAC has been found to benefit mood and healthy brain functions.

 

Reference: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3036554/

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC330079/

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3967529/

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5241507/