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By Frances Albrecht, C.N., M.S.

By now, most of us are familiar with the "antioxidant ACES": vitamins A, C, E and the mineral selenium. But did you know there's a whole new generation of antioxidants? Key antioxidant enzymes such as glutathione peroxidase and superoxide dismutase; plant pigments such as bioflavonoids found in milk thistle and Ginkgo biloba; flavonoids including proanthocyanidins; and other "accessory nutrients" such as N-acetylcysteine, co-enzyme Q₁₀ or alpha-lipoic acid perform vital antioxidant and detoxification activities.

    The beneficial effects of antioxidants—substances that inhibit oxidation damage to cells—are recorded in hundreds of studies, showing that antioxidants protect against cancer, heart disease, arthritis, cataracts and other degenerative conditions. Antioxidants also offset a number of age-related problems such as dry skin, declining immune function and memory loss.

    Found naturally in many foods and herbs and sometimes in the body, antioxidants protect the body's tissues by destroying free radicals. Free radicals are oxidizing molecules that lack one or more electrons and seek stability by stealing electrons from other molecules such as those found in healthy cells. Free radicals are formed naturally in the body as a result of metabolism and by the immune system. They're also by-products of chemical reactions such as those related to smoking, pollution, exposure to toxins, overexercise, injury, stress, rancidification of fats and oils, chemotherapy, and radiation.

    Free radicals are both beneficial and harmful. The immune system utilizes them to help fight viruses and bacteria by releasing a damaging "oxidative burst" of free radicals that kills invaders and immune cells. The body later regenerates its lost immune defenders.

    Yet, free radicals can also harm the body. Increasing the internal load of free radicals whether through natural bodily processes or environmental causes can result in premature aging. Much like the rusting action of oxygen on your car fender or the browning of freshly cut fruit, oxidation ages tissues through cellular damage and destruction. Free radical activity can also result in disease through a process called oxidative stress, which results when free radicals replicate and overwhelm the body. Oxidative stress is believed to be a causative factor in the disease progression of HIV. Unchecked free radicals can accelerate plaque deposition in arteries. Free radicals can also cross-link proteins and/or DNA molecules (cross-linking in skin cells results in dryness, wrinkles and reduced springiness to touch); and damage nucleic acids of DNA, altering the genetic code and increasing the likelihood of abnormal cell replication and cancerous cell changes.

    The amount of oxidative stress the body undergoes depends on its ability to counteract oxidizing damage with the necessary antioxidant response. The body can diminish these harmful effects
with the help of antioxidants that "quench" oxidation reactions by donating their own electrons. If a compound easily donates electrons, it has high reducing or "antioxidant" powers. These donated electrons are then restored or recycled back to the antioxidants through reactions with other antioxidants. For this reason, antioxidants work best together.

    Normally, the body defends itself against oxidative damage by manufacturing a network of free radical scavengers composed of enzymes such as glutathione peroxidase (GSH), superoxide dismutase (SOD) and catalase. These highly active, internally produced antioxidants bind to and neutralize free radicals, forming our front line of disease prevention. Minerals such as zinc, copper and manganese often combine with enzymes to counter the effects of free radicals. Vitamins A, E and C work independently to scavenge free radicals and provide nutritives that help produce antioxidant enzymes.

Our Sad Dietary State

The good news is that most antioxidant nutrients are easily obtained through dietary sources. The bad news is the Standard American Diet (appropriately abbreviated as "SAD") doesn't contain enough of the most beneficial foods such as whole grains, fresh fruits and vegetables, cold-water fish, and nuts and seeds. In 1991, the National Health and Nutrition Education Study of American eating habits found that the average American consumed a mere 1.9 servings of fruits and vegetables per day, and that included french fries as a vegetable source. This amount obviously falls short of the five to nine servings per day currently recommended by the USDA Food Guide Pyramid. Instead, the American diet contains higher proportions of processed foods with attendant nutrient losses. The diet also contains large amounts of fat, especially saturated and polyunsaturated fats that can be easily oxidized. Particularly troubling is the overconsumption of deep-fried foods such as french fries and chips. At high temperatures, oils—especially polyunsaturated oils— become oxidized, increasing the body's burden of free radicals.

    Considering all these factors as well as the enormous health costs and devastating disease rates that experts believe could be reduced through enhanced nutrition, antioxidant supplementation is considered a good bet for low-cost health maintenance.

New Antioxidants on the Block

Alpha-lipoic acid is a form of antioxidant made in trace amounts in the body. Its reduced form, dihydrolipoic acid, donates electrons to other compounds. This ability makes alpha-lipoic acid invaluable in recycling or restoring other oxidized forms of antioxidants back to their useful states. Unlike most other antioxidants that offer protection for specific water-soluble or fat-soluble environments, alpha lipoic acid appears to be an all-purpose antioxidant that offers general protection from all types of oxidizing damage. It crosses cell membranes and works as an antioxidant in both aqueous and lipid parts of the body including the brain.

    Alpha-lipoic acid may provide protection against liver damage during cancer treatment. This antioxidant appears to have no toxic side effects even when taken in large amounts; in clinical studies, 300 to 600 mg. per day is the usual dose.

Cysteine and glutathione: Cysteine is a main building block of protein and muscle. In the body, it can be converted to glutathione, which when combined with selenium, is converted to one of the body's primary intracellular water-soluble antioxidant defenders, glutathione peroxidase. Glutathione is necessary for white blood cell function and is used by the liver to help detoxify drugs. Optimal levels of glutathione are needed for the immune defenses of the lungs; deficiencies may increase the risk of lung infections.

    One form of cysteine called N-acetylcysteine (NAC) is a commonly used supplement. In the body, NAC is converted to glutathione. NAC may be a useful supplement in HIV treatment due to its immune boosting and detoxification functions and because people with HIV are almost always deficient in glutathione. NAC works best when taken with vitamin C, alpha-lipoic acid and L-glutamine, another amino acid that helps maintain optimal antioxidant status.

Bioavailable flavonoids (bioflavonoids) are a group of plant pigments with antioxidant, anti-inflammatory, antiallergic, antiviral, and anticarcinogenic activities. Found in almost every fruit and vegetable, some bioflavonoids supplant sites on cells normally favored by hormones including estrogen that influence cancer growth, barring their attachment. Bioflavonoids are found closely associated in nature with vitamin C and enhance its therapeutic effects. They're useful in the treatment of a wide range of disease conditions due to their ability to modify allergic reaction and reduce capillary fragility.

    Better known plants rich in bioflavonoids include milk thistle (Silybum marianum) and Ginkgo biloba. Silymarin, a component of milk thistle, is an antioxidant with liver-protective effects. Ginkgo biloba contains bioflavonoids that can also improve the flow of blood to the brain. Ginkgo has been shown to be effective in the treatment of age-associated memory function, short-term memory loss and hearing loss, according to the Encylopedia of Natural Medicine by Michael Murray, N.D., and Joe Pizzorno, N.D. (Prima).

    One group of bioflavonoids called proanthocyanidins (condensed tannins), is found in deep red-blue colored berries such as blueberries and blackberries, in pine bark, grape seeds, green tea and persimmons. These antioxidants help stabilize collagen structures, which hold tissues together (Journal Francais de Opthalmologie, 1988, vol. 11). Consumption of natural or supplemental sources of these antioxidants may offer significant protection against the development of osteoporosis. In addition, some bioflavonoids help prevent tumor growth by inhibiting angiogenesis (Encyclopedia of Natural Medicine). Proanthocyanidins also help to neutralize free radicals involved in the breakdown of tissue and blood vessel walls (Arzneimittel-Forschung, May 1994, vol. 44).

    Another group of bioflavonoids called gallates has been found in grape seeds. Gallates are powerful antioxidants that prevent the oxidation of low-density lipoprotein (LDL), thus reducing the risk of coronary heart disease (Biological & Pharmaceutical Bulletin, January 1995, vol. 18). Green tea, too, contains a variety of gallate compounds. The most active antioxidant compound in green tea appears to be epigallocatechin gallate, which seems to have potent anticancer properties (Preventive Medicine, July 1992, vol. 21).

    The best way to ensure an adequate intake of bioflavonoids is to regularly consume a variety of fresh, preferably organic, fruits and vegetables. If choosing to supplement, take a mixed bioflavonoid supplement of 500 to 1,000 mg. once or twice a day for general antioxidant protection to enhance blood vessel strength and support the actions of vitamin C.

    CoQ₁₀ is particularly useful in the treatment and prevention of many heart-related conditions. It provides cellular protection from oxidative damage in fat-soluble mediums such as cell membranes, which are composed of fatty acids. In medicine CoQ₁₀ has shown therapeutic value in the treatment of cardiovascular conditions, AIDS, high blood cholesterol and high blood pressure (Quarterly Review of Natural Medicine, Fall 1994).

    Unlike other antioxidants, large amounts of CoQ₁₀ are difficult to obtain through dietary sources alone. Therapeutic doses of CoQ₁₀ have ranged from 30 to 100 mgs. per day. The best dietary sources of CoQ₁₀ are fish and fish oils, organ meats and the germs of whole grains. Wholegrain germs are also the best source of vitamin E, which synergistically enhances the effects of CoQ₁₀ . 

Frances Albrecht, C.N., is president of Nutrition Education Services and a Distance Learning Instructor at Bastyr University.

This story is produced through the Bastyr University Health Information Project, funded by INDENA, U.S.A., raw material suppliers of standardized herbal extracts. Bastyr University offers a program in naturopathic medicine (N.D.); bachelor's degrees in the natural health sciences; and master's degree programs in nutrition, acupuncture and Oriental medicine. For information, contact Bastyr University, 14500 Juanita Drive NE, Bothell, WA 98011; 206-823-1300.

Reprinted with permission from the March 1997 issue of Delicious! Magazine, a publication of New Hope Communications, Boulder, CO.