Glutathione, the body’s master antioxidant, and detoxifier is one of the 14 “Superfoods” listed in SuperFoods Rx: Fourteen Foods That Will Change Your Life, co-authored by Dr. Steven Pratt.
Glutathione levels cannot be increased to a clinically beneficial extent by orally ingesting a single dose of glutathione. (1) This is because glutathione is manufactured inside the cell, from its precursor amino acids, glycine, glutamate, and cystine.
Hence food sources or supplements that increase glutathione must either provide the precursors of glutathione or enhance its production by some other means.
The manufacture of glutathione in cells is limited by the levels of its sulfur-containing precursor amino acid, cysteine.
Cysteine – as a free amino acid – is potentially toxic and is spontaneously catabolized or destroyed in the gastrointestinal tract and blood plasma. However, when it is present as a cysteine-cysteine dipeptide, called cystine, it is more stable than cysteine.
Consuming foods rich in sulfur-containing amino acids can help boost glutathione levels. Here are some food sources and dietary supplements that help boost glutathione levels naturally.
1. N-Acetyl-Cysteine (NAC)
It is derived from the amino acid L-Cysteine and acts as a precursor of glutathione. NAC is quickly metabolized into glutathione once it enters the body. It has been proven in numerous scientific studies and clinical trials, to boost intracellular production of glutathione, and is approved by the FDA for the treatment of acetaminophen overdose. Because of glutathione’s mucolytic action, NAC (brand name Mucomyst) is commonly used in the treatment of lung diseases like cystic fibrosis, bronchitis, and asthma.
2. Milk Thistle, Silymarin
Milk thistle is a powerful antioxidant and supports the liver by preventing the depletion of glutathione. Silymarin is the active compound of milk thistle. It is a natural liver detoxifier and protects the liver from many industrial toxins such as carbon tetrachloride, and more common agents like alcohol.
3. Alpha Lipoic Acid
Made naturally in body cells as a by-product of energy release, ALA increases the levels of intracellular glutathione and is a natural antioxidant with free radical scavenging abilities. It has the ability to regenerate oxidized antioxidants like Vitamin C and E and helps to make them more potent. ALA is also known for its ability to enhance glucose uptake and may help prevent the cellular damage accompanying the complications of diabetes. It also has a protective effect on the brain.
4. Natural Foods That Boost Glutathione Levels
Asparagus is a leading source of glutathione. Foods like broccoli (2), avocado, and spinach are also known to boost glutathione levels. Raw eggs, garlic, and fresh unprocessed meats contain high levels of sulfur-containing amino acids and help to maintain optimal glutathione levels.
5. Undenatured Whey Protein Isolate
Whey protein contains proteins like alpha-lactalbumin which is rich in sulfur-containing amino acids. Heating or pasteurization destroys the delicate disulphide bonds that give these proteins their bioactivity. Undenatured whey protein is a non-heated product that preserves bioactive amino acids like cystine. It has been shown in numerous scientific studies and clinical trials to optimize glutathione levels.
6. Curcumin (Turmeric)
Treatment of brain cells called astrocytes, with the Indian curry spice, curcumin (turmeric) has been found to increase expression of the glutathione S-transferase and protect neurons exposed to oxidant stress. (3)
7. Balloon Flower Root
Changkil saponins (CKS) isolated from the roots of the Chinese herbal medicine, Platycodon grandiflorum A. DC (Campanulaceae), commonly called Balloon Flower Root or Jie Geng, have been found to increase intracellular glutathione (GSH) content and significantly reduce oxidative injury to liver cells, minimise cell death and lipid peroxidation. (4)
Selenium is a co-factor for the enzyme glutathione peroxidase. Selenium supplements have become popular because some studies suggest they may play a role in decreasing the risk of certain cancers, and in how the immune system and the thyroid gland function. However, too much selenium can cause some toxic effects including gastrointestinal upset, brittle nails, hair loss, and mild nerve damage.
1. The systemic availability of oral glutathione
Witschi A, Reddy S, Stofer B, Lauterburg BH. [Eur J Clin Pharmacol. 1992;43(6):667-9.]
2. Dietary approach to attenuate oxidative stress, hypertension, and inflammation in the cardiovascular system
Wu L, Ashraf MH, Facci M, Wang R, Paterson PG, Ferrie A, Juurlink BH. [Proc Natl Acad Sci U S A. 2004 May 4;101(18):7094-9. Epub 2004 Apr 21.]
3. Can Curry Protect Against Alzheimer’s?
American Physiological Society (APS) Press release; 16-Apr-2004
4. Protective effect of saponins derived from roots of Platycodon grandiflorum on tert-butyl hydroperoxide-induced oxidative hepatotoxicity
Lee KJ, Choi CY, Chung YC, Kim YS, Ryu SY, Roh SH, Jeong HG. [Toxicol Lett. 2004 Mar 7;147(3):271-82.]