Glutathione. Our Body's #1 Defense Against Aging And Disease.
By Elliott Goodman
Is it possible to slow down the aging process and delay the onset of disease? Research is being done to gain a deeper insight into the causes of the processes of aging, disease and death. Researchers hope this will lead to methods to slow down aging. A lot of research points to the "free radical theory of aging and disease." We all have two ages: our biological age (how many years we have been alive) and our functional age (the condition of our body-how youthful and healthy we are). The free radical theory says our functional age may be a product of the levels of antioxidants in our body, especially a substance called glutathione. In animal studies, researchers have been able to actually slow down aging and disease with the use of certain antioxidants.1 Maintaining antioxidant levels may help humans in either extending our life or improving our vitality despite advancing biological age.
Aging and Disease
First proposed by Harman in 1981, more and more researchers are embracing the free radical theory of aging.2 This point of view suggests that free radicals (unstable oxygen molecules) play a major role in the cause and the progression of many diseases. One of the biological changes associated with aging is an increase in free radical formation with resulting damage to cellular processes. Also, the use of prescription drugs increases free radical and toxin production. Oxygen therapy may also increase free radical production as does radiation and environmental factors. Prolonged oxidative stress leads to irreversible damage and cell death. Our body is a battleground where there are forces trying to destroy us (oxidants) and those that protect us from them (antioxidants). Eventually, the balance tips toward the oxidants (and other toxins that kill and mutate cells) and we begin to lose the battle. We age, become debilitated and eventually die of diseases such as heart attack, stroke and cancer. Researchers have suggested that maintaining high antioxidant levels in the body may increase longevity by influencing the immune system and by reducing age-related diseases or delaying their onset.
Discovery of Glutathione
The existence of glutathione was theorized in 1888 when scientists noticed the antioxidant properties of a water extract of baker's yeast. They later found it was present in animal tissue extracts. It was identified in baker's yeast by Hopkins in 1921 and named "glutathione". It was first synthesized in 1952 as "L-glutathione". There are many antioxidants functioning in our body. Most people are familiar with vitamins C, A and E. And there are also substances in plants (phytochemicals) that can function as antioxidants.
• Glutathione (in its various forms) is believed to be the major protection system in the body against free radicals.
• Glutathione is essential in protecting our cells from toxins (produced within our body and entering our body from the environment) which cause cell mutation and cell death.
• Glutathione protects our cells from radiation damage.
• Glutathione can neutralize the toxic by-products of medications.
• Glutathione removes toxic heavy metals such as mercury from the body.
• Studies show glutathione may actually perform repairs on damaged DNA within our cells.
• Glutathione recycles vitamins C and E after they have been oxidized by free radicals so those vitamins can be used again.
Glutathione is found in the watery part of all of our cells and in our bodily fluids and tissues. Interestingly, it is especially abundant where we need it most-in the parts of our body where we are most vulnerable to attacks from free radicals, toxins, radiation etc.
How We Get Glutathione
Our body makes most of its glutathione supply. And we also get it from food such as fresh vegetables and fruits. Also, our body produces various enzyme forms of glutathione such as glutathione peroxidase which is believed to be the only active site of selenium in the body. Although there are other important antioxidant enzymes in the body, "...glutathione peroxidase was found to be much more effective than both catalase and superoxide dismutase, the latter being particularly inefficient."3
Glutathione and Aging
As a result of performing all of its life and health-preserving functions, the levels of glutathione in our body can become depleted. This impairs our primary cell protection. As levels of free radicals and toxins increase (with aging, disease, environmental factors etc.), our level of glutathione declines. We become more and more defenseless against increasing attacks from free radicals, toxins, radiation etc.
Researchers are attempting to correlate glutathione levels in individuals with incidence of diseases and other signs of aging as well as life expectancy. Some promising studies are reviewed in Free Radicals and Aging. "The free radical theory of aging suggests that oxygen free radicals may be involved in the aging process. Thus, changes in antioxidant mechanisms may occur with aging. Since glutathione is one of the most effective antioxidant systems in the cell, its metabolism may change with aging." "...we describe experiments which show the involvement of glutathione in the aging process and which provide a rationale for the administration of antioxidants to old organisms to protect them against some of the changes that occur with aging."1
A study (performed by the University of Michigan School of Public Health and the University of Louisville School of Medicine) compared glutathione levels in elderly people with various disease conditions (arthritis, high blood pressure, heart disease, circulatory symptoms, diabetes, stomach symptoms, and urinary tract infection). The study showed that, in a sample of independently living elderly, a person's glutathione status accounted for the largest factor in the incidence of disease. "For every illness, except urinary tract infections, those subjects who possessed the condition had a lower mean glutathione level than those without the condition." The researchers concluded that this is evidence of "an association of higher glutathione with better physical health in a sample of community-based elderly." The study concluded that evidence that "low levels of glutathione are associated with a number of morbid states is rapidly accumulating."4
The Primary Functions of Glutathione in the Body
A search of two of the world's largest data bases of medical and scientific literature (MedLine and CancerLit) reveals more than 19,000 published studies and articles on glutathione in humans. And the number of studies on the role of glutathione is rapidly growing each year. This intense interest by the medical and scientific community is a strong indication of just how important glutathione is in the human body. "Glutathione has several major physiological functions: protecting cells against destructive effects of reactive oxygen intermediates and free radicals; detoxifying external substances such as drugs and environmental pollutants, maintaining red cell membrane stability; enhancing immunological function through its effects on lymphocytes. These widespread functions suggest that the level of glutathione may have major health effects on the molecular, cellular and organ levels of individuals." 4
"Glutathione plays a central role in preventing cellular injury and mutation and may be a protective factor in cancer and aging, cardiovascular disease and the immune dysfunction of HIV infection."5
Decreased tissue glutathione concentrations have been reported in many diseases. Glutathione is decreased in the liver of patients with alcoholic liver disease or symptomatic Wilson's disease. Glutathione levels are low in the brain of patients with Parkinson's disease and in the lining of the lung of patients with adult respiratory distress syndrome or idiopathic pulmonary fibrosis. In HIV positive individuals, low glutathione levels may increase the risk for opportunistic infections by depressing the immune function. The importance of glutathione for host defense and detoxification in the lung is suggested by the relatively high susceptibility of AIDS patients to lung infections.6
Glutathione and Cardiovascular Disease
The leading cause of death in the United States is heart disease. Cholesterol by itself is not the culprit but rather the attack on cholesterol by free radicals. Cholesterol circulates in our blood vessels and is attacked by hydrogen peroxide and other free radical molecules which turn it into plaque. This destruction of fatty substances is called "lipid peroxidation". The plaque sticks to the sides of the blood vessels causing heart disease (atherosclerosis) and it eventually blocks the blood flow causing a stroke or a heart attack. Researchers believe glutathione may play a crucial in protecting us from heart disease.7
"Oxidative stress can result in glutathione depletion, lipid peroxidation, membrane damage and DNA strand breaks..." "Some degree of oxidative stress occurs in most, if not all, human diseases, and the major question to be answered is whether it makes a significant contribution to the disease pathology. In the case of atherosclerosis ...oxidative damage does indeed make an important contribution to plaque development."8
"The continuous exposure to blood components, including pro-oxidants, makes the blood vessel wall susceptible to oxidative stress and free radical mediated reactions. It has been proposed that free radicals are involved in the initiation and progression of various cardiovascular diseases including arteriosclerosis. Thus the adequacy of the defense systems against free radicals is critical for the susceptibility of blood vessel wall to oxidative damage. Among the enzymatic systems capable of protecting the cell against oxidative injury, selenium dependent glutathione peroxidase, glutathione reductase and glutathione transferase play a crucial role."9
Glutathione and Cancer
It is well documented that the incidence and death rates from cancer increase progressively with age in humans. A similar age-related pattern in tumor incidence is also observed in experimental animals. Except for certain cancers that occur mostly in children and young adults, the incidence of most cancers increase exponentially with age, reaching a maximum between 50 and 70 years of age. This problem is likely to get worse as the percentage of elderly in the population continues to increase.
It has been suggested that the underlying mechanisms of aging and cancer are closely related. There is an accumulation of non-repairable cell damage which occurs in cells over time. Damage to the DNA inside the cell can cause the cell to mutate and become cancerous. This may explain the occurrence of tumors. Researchers at the American Health Foundation said "One line of evidence comes from our own results and those of others, which suggest that a glutathione deficiency is a general feature of aging tissues. Based on the well-known roles of this compound in cellular defense systems, we hypothesize that the loss of glutathione will lead to an increased susceptibility to carcinogens. Human studies have revealed that a large segment of the elderly population has low blood glutathione levels. Studies are underway to determine if these glutathione deficient subjects are at greater risk to specific diseases and environmental insults"10
Additional Protective Rolls of Glutathione
The lenses of the eyes have a high glutathione content. Since the eyes are exposed to light and oxygen, they are at high risk of oxidative damage resulting in cataracts. The prime protection from this damage may be glutathione. Since glutathione levels in the lens decline with age, the elderly are susceptible to cataracts,11 age-related macular degeneration12 and glaucoma.13
Since our lungs are where oxygen (and pollution) enters our body, they are particularly susceptible to cell damage. There are many studies investigating the role of glutathione in protecting the lungs. It has been found that patients with ARDS (Adult Respiratory Distress Syndrome) have depressed blood and red cell glutathione levels. The same deficiency is observed in individuals with intrinsic asthma.
Another area of research has to do with the brain. The level of glutathione in the brains of Parkinson's disease patients is low. This may indicate a state of oxidative stress. "The action of toxins or the altered metabolism of dopamine may lead to oxidative stress in substantia nigra [brain], thereby inducing dopamine cell death and the onset of Parkinson's disease. Postmortem studies showing a depletion of reduced glutathione... suggest the occurrence of an ongoing toxic process in substantia nigra involving free radical mechanisms."14
What Can We Do To Maintain The Levels of Glutathione in Our Body?
Moderate exercise can help, but extreme physical exertion increases free radical attacks. "Aging appears to be accelerated because of a decrease in the antioxidant capacity of tissues reflected in a decreased plasma glutathione level. This age-dependent change could be partly compensated by physical training. Skeletal muscle appears to be able to deliver glutathione into circulation with the adaptation of muscle to exercise training reflected in an increased plasma glutathione level in the trained subject."15
Attempts to increase glutathione levels by consuming synthetic amino acids are problematic. Cystine, for example is not easily soluble and may precipitate kidney stones. There has been research on a drug N-acetylcysteine. It may raise glutathione levels but its safety and long-term effectiveness have not been demonstrated.
There are mixed results in raising blood levels with synthetic L-glutathione both orally and by injection. Most researchers believe supplementation with L-Glutathione is not effective in the long run.
We believe natural food may prove to be the safest and best answer!
Eating a diet rich in sulfur-containing proteins gives you the raw materials the body uses to produce glutathione internally. Maintaining good levels of vitamin C and vitamin E helps preserve the body's glutathione level by taking some of the workload off its shoulders. But most important may be the fact that foods contain glutathione. Dr. Bruce Ames, considered by many to be one of the foremost experts on free radicals in pathology and aging states "Glutathione is present in food and is one of the major antioxidants and antimutagens..."16
Unlike the synthetic L-glutathione which is poorly utilized, we may be able to utilize the glutathione nature provides for us in natural foods. Recent studies, supported in part by the American Institute for Cancer Research, indicate that glutathione levels in our body are influenced by the glutathione content of the foods we eat. For example, the studies show that vegetarians have higher blood levels of glutathione than non-vegetarians. Cooking mostly destroys the glutathione content of foods.
Since most people's diets are lacking in fresh vegetables and fruits, one promising new development is a method of concentrating the glutathione content of food. Baker's yeast (where glutathione was first discovered) contains 0.4% glutathione. A partial extraction is performed which concentrates the glutathione level to 5.0% (all of it in reduced form and still intact, still part of the food matrix). This is pressed into tablets and marketed as Foodform® Glutathione which we consider one of our must important products.
Each tablet of Foodform Glutathione provides the reduced glutathione content of over two pounds of fresh vegetables. We believe that, short of making very difficult lifestyle changes, Foodform Glutathione may offer the best approach for us to maintain adequate glutathione levels. Each tablet of Foodform Glutathione also contains 100 mcg. of Foodform Selenium and 1.7 mg of Foodform Vitamin B-2. The selenium and B-2 are added to provide our body with the raw materials it needs to produce the most important antioxidant enzyme-Glutathione Peroxidase.
1. Vina, J. et.al. Effect of aging on glutathione metabolism. Protection by antioxidants. Free Radicals and Aging (1992) Birkhauser Verlag, Basel/Switzerland. pp. 136-144.
2. Harman, D. The free radical theory of aging. Proceedings National Academy of Science USA (1981) 78:7124-7128.
3. Raes, M. et.al. Comparative study of the enzymatic defense systems against oxygen-derived free radicals: the key role of glutathione peroxidase. Free Radical Biology and Medicine (1987) 3 (1):3-7.
4. Julius, M. et.al. Glutathione and morbidity in a community-based sample of elderly. Journal of Clinical Epidemiology (1994) Vol. 47, No. 9, pp. 1021-1026.
5. Flagg, E.W. et. al. Plasma total glutathione in humans and its association with demographic and health-related factors. British Journal of Nutrition (1993) 70:797-808.
6. Bray, T.M., Taylor, CG Enhancement of tissue glutathione for antioxidant and immune functions in malnutrition. Biochemical Pharmacology (1994) 47:12 pp. 2113-2123.
7. Guidi, G. et.al. Platelet glutathione peroxidase activity is impaired in patients with coronary heart disease. Scandinavian Journal of Clinical Laboratory Investigation (1986) Oct;46 (6):549-51.
8. Halliwell, B. The role of oxygen radicals in human disease, with particular reference to the vascular system. Haemostasis (1993) Mar;23 Suppl 1():118-26.
9. Mezzett,i A. et.al. Glutathione peroxidase, glutathione reductase and glutathione transferase activities in the human artery, vein and heart. Journal of Molecular and Cellular Cardiology (1990) Sept;22 (9):935-8.
10. Richie, J. The role of glutathione in aging and cancer. Experimental Gerontology (1992) Vol. 27, pp. 615-626.
11. Reddy, V.N. Glutathione and its function in the lens-an overview. Experimental Eye Research (1990) Jun;50 (6):771-8.
12. Prashar, S. et.al. Antioxidant enzymes in red blood cells as a biological index of age related macular degeneration. Acta Ophtalmol (Copenh) (1993) Apr;71 (2):214-8.
13. Bunin, A. et.al. A glutathione deficiency in open-angle glaucoma and the approaches to its correction. Vestn Oftalmol (1992) Jul-Dec;108 (4-6):13-5.
14. Jenner, P. What process causes nigral cell death in Parkinson's disease? Clinical Neurology (1992) May;10 (2):387-403. 15. Kretzschmar M Aging, training and exercise. A review of effects on plasma glutathione and lipid peroxides. Sports Medicine (1993) Mar;
16. Ames, B. Dietary carcinogens and anticarcinogens. Oxygen radicals and degenerative diseases. Science (1983) 221:1256-1264.
This article is intended solely for informational and educational purposes, not for medical advice. The reader should consult a physician for any health problems or questions they may have.
Copyright © 1998 Elliott Goodman. All rights reserved.
Foodform is a registered trademark of IntraCell Nutrition Inc.