Glutathione
Glutathione isn't technically a phytonutrient, since it's a compound that is produced by the body inside the cell. However the cell requires certain precursors to be there in order to make glutathione, and this article will focus on how to have the right building blocks available to make this important nutrient.
Glutathione is a tripeptide, synthesized from the three amino acids glycine, glutamic acid, and cysteine. It is the sulphur bearing cysteine peptide that gives glutathione its properties as a strong antioxidant. This compound, called a thiol, can neutralize toxins and free radicals by giving up an electron. Cysteine is the rarest of the three amino acids needed to make glutathione, therefore it is this availability that determines how much your body can make. Researchers have found that if you take glutathione orally, even in large amounts, it doesn't raise the levels in your plasma and liver because it just isn't absorbed very well. However eating substances rich in cysteine does increase glutathione levels in the body.
Glutathione's main job is to repair oxidative stress in the cells, or act as an antioxidant. Viruses, bacteria, environmental toxins, heavy metals, medications and the aging process can all cause oxidative stress. Scientists estimate that our glutathione levels drop an average of 10% every decade, putting us at a greater risk for cell damage the older we get. Glutathione helps the liver to remove toxic drugs and chemicals from the body. Hospital patients with AIDS, cancer, chronic infections and other serious diseases almost always have low levels of glutathione. Glutathione has been used in cancer treatments since 1984, and is commonly used in hospitals to treat Tylenol overdose or heavy metal poisoning. It is being studied as a treatment for cystic fibrosis because of its ability to break up mucus. A German study published in 2000 concluded that supplementing with cysteine (to raise glutathione levels) did not have an effect on the immune system of healthy individuals, but significantly enhanced the immune response in individuals with HIV or other diseases where the glutathione level was low.
Being an amino acid, cysteine is found in high protein foods, especially ricotta and cottage cheese, yogurt, pork, sausage, chicken, turkey, duck and other poultry. Plant sources include wheat germ (or whole wheat products), oats, red peppers and sulphurous vegetables such as broccoli, brussel sprouts, cauliflower, onion and garlic. Your body can make cysteine from another amino acid, methionine, which is found widely in high protein foods such as meats, and also in sunflower seeds, pumpkin seeds, sesame seeds, peanuts and lentils.
Some people take or recommend whey protein as a high cysteine supplement to increase glutathione levels. Whey protein is high in cysteine, but is easily damaged during pasteurization and processing. If you buy whey protein make sure it is bioactive and made from non-denatured proteins, meaning the protein structure is not broken down. Cysteine supplements are not absorbed very well into the system and can actually be toxic, doing more harm than good. N-Acetyl-Cysteine (NAC) is a synthetic version of cysteine that is absorbed more readily, but also has toxic side effects if you take too much. It also depletes your zinc, making supplementation of this mineral necessary. Silymarin, or milk thistle can increase your levels of glutathione.
The information on this page is not meant to be used in treatment of medical conditions. Please seek the advice of a physician about any medical condition or symptom. Those with medical conditions should consult a medical professional about the appropriateness of taking dietary supplements or diet therapy, and how these methods will interact with their medications.
LINKS
Glutathione on MedicineNet.com.
Mark Hyman, MD discusses glutathione on The Huffington Post.