May 13, 2009
A: Glutathione is an important molecule essential for optimal performance of every cell in the body. A deficiency is thought to increase the risk of cancer and other diseases. Research is finding glutathione-boosting supplements may help treat some diseases, but more research is needed to test the value for healthy individuals.
A powerful antioxidant, glutathione neutralizes free radicals, reducing damage to DNA, cell membranes, and organelles. It also regulates gene expression, protein synthesis, cell reproduction, cell signaling, and immune response. Thousands of studies are leading scientists to theorize a deficiency may affect the likelihood or progression of cancer, Alzheimer's disease, liver disease, cystic fibrosis, heart attack, stroke, diabetes and HIV/AIDS.
Glutathione is a tripeptide the body manufactures from three amino acids: glutamate, glycine, and cysteine. Smoking, alcohol, caffeine, acetaminophen, drugs, vigorous exercise, and chemical pollutants can deplete glutathione in cells. If it is not replaced malfunctions occur.
Glutathione occurs naturally in many foods but is particularly high in cruciferous vegetables such as broccoli, cauliflower, Brussels sprouts, cabbage, kale, bok choy, mustard greens, turnips, and kohlrabi. Other sources include asparagus, avocado, squash, okra, potatoes, spinach, garlic, raw tomatoes, apples, grapefruit and carrots. Glutathione is absorbed well from foods but research finds glutathione supplements are ineffective. In one study glutathione increased 26 percent from a diet rich in cruciferous vegetables.
Nutrients, such as vitamin C, Curcumin (the spice Tumeric), Vitamin B-12, and selenium assist in glutathione production. All can be obtained from a healthy diet, rich in non-fat dairy products, fruits, vegetables, fresh meats (not processed), and spices.
Experts believe people who routinely eat a healthy diet are not deficient in glutathione but those with poor diet or disease states may be, and cysteine, essential for its manufacture, could be part of the problem.
A health study of 32,000 women found those with low levels of cysteine had a 50 percent greater chance of getting breast cancer. Cysteine is a non-essential amino acid, which means your body can make it from other substrates, like B6, B12, folic acid and others. Cysteine is also found in foods like poultry, yogurt, egg yolks, wheat germ, oats, and some vegetables. Dietary supplements of cysteine can be toxic and are not recommended.
Whey protein, obtained from milk, is rich in cysteine but only in a form that has not been altered by heat from pasteurization. Called un-denatured whey protein, it can be found in health food stores. Immunocal is a supplement made of an un-denatured type of cysteine and other components. Both whey protein and Immunocal have been shown in research to improve glutathione levels in cancer and AIDS patients. Research is ongoing to determine if this will improve disease states long-term.
Focusing on a healthy, well rounded diet is the best bet to insure adequate levels of cysteine and glutathione.
Joan Endyke is a registered dietitian with a master's degree in nutrition and food science. She is also a certified personal trainer. She is the nutrition director at Fitness Unlimited.
Readers may send questions about nutrition to Endyke at Fitness Unlimited, 364 Granite Ave., Milton, MA 02186 or by e-mail to firstname.lastname@example.org.
The information in this column is not intended to diagnose individual conditions. Readers should see their doctors about specific problems.