Chapter 7
Supplements for Control of Oxidation
Antioxidants are important for controlling the activity of the highly reactive oxygen molecules known as free radicals, because unchecked free-radical activity is what leads to the cellular damage known as oxidation and the cycle of glycation and inflammation that follows, causing additional damage and dysfunction. When it comes to antioxidant supplementation, however, it is the overall collection of several antioxidants that is important, rather than any single "super" antioxidant. This is what scientists call the "antioxidant network," and it is made up of five major classes of antioxidants : vitamin E, vitamin C, carotenoids, bioflavonoids, and thiols. Your cells need representatives from each of these categories in order to mount the strongest antioxidant defense.
Think of it this way: If you had the best home run hitter in the world, but poor pitching and fielding, then your baseball team would not be the best. The same thing applies to your antioxidant defenses. Green tea, vitamin E, pine bark, and beta-carotene are all wonderful antioxidants on their own, but combining them to create a network that works together in different parts of the body and against different types of free radicals is the most effective way to go. Some of the top picks are beta-carotene (natural), lycopene, lutein, vitamin E (natural), vitamin C, alpha-lipoic acid, green tea, selenium, zinc, grape seed, and pine bark. But there are many other choices of nutrients and herbal extracts and plant extracts that also possess wonderful antioxidant properties, several of which are summarized in this chapter.
Antioxidants: A General Discussion
The term "antioxidant" refers to the ability possessed by numerous vitamins, minerals, and other phytochemicals to serve as protection against the damaging effects of highly reactive molecules known as free radicals. Free radicals have the ability to chemically react with, and damage, many structures in the body. Particularly susceptible to oxidative damage are the cell membranes of virtually all cells, especially those in the skin, because of the skin's high lipid content and its vulnerability to ultraviolet rays from the sun.
The free-radical theory of aging and disease promotion holds that through a gradual accumulation of microscopic damage to our cell membranes, DNA, tissue structures, and enzyme systems, we begin to lose function and become predisposed to disease. In the case of athletes and other avid exercisers, oxidative damage may be elevated due to increased production of free radicals during intense activity. Although the body increases its production of endogenous antioxidant enzymes (glutathione peroxidase, catalase, superoxide dismutase) when it is under stress, it can be theorized that supplemental levels of exogenous or dietary antioxidants may be warranted to prevent excessive oxidative damage to muscles, mitochondria, and other structures.
Thousands of studies have clearly documented the beneficial effects of dozens of antioxidant nutrients. There is certainly no shortage of nutrients and phytochemicals that possess significant antioxidant activity in the test tube. Increased dietary intake of these nutrients-for example, vitamins C and E, minerals such as selenium, and various phytonutrients such as extracts from grape seed, pine bark, and green tea-have all been linked to reduced rates of oxidative damage, as well as to reduced incidence of chronic illnesses such as heart disease and cancer.
At the typically recommended levels, the majority of antioxidants appear to be quite safe. For example, vitamin E, one of the most powerful membrane-bound antioxidants , also has one of the best safety profiles. Doses of 100-400 IU (international units) have been linked to significant cardiovascular benefits with no side effects. Vitamin C, another powerful antioxidant, can help to protect and restore the antioxidant activity of vitamin E, and it is considered safe up to doses of 500-1,000 mg. Higher doses of vitamin C are not recommended because of concerns that such levels may cause an "unbalancing" of the oxidative systems and actually promote oxidative damage instead of preventing it. Another popular antioxidant, beta-carotene, is somewhat controversial as a dietary supplement. Although diets high in fruits and vegetables might deliver approximately 5-6 mg of carotenes daily, these would include a mixture of beta-carotene and other naturally occurring carotenoids. Concern was raised several years ago by studies in which high-dose beta-carotene supplements appeared to promote lung cancer in heavy smokers. Those studies provided unbalanced synthetic beta-carotene supplements of 20-60 mg-about five to ten times the levels that could reasonably be expected in the diet.
The four key nutritional antioxidants -vitamins C and E, beta-carotene, and selenium-are well studied, widely available as dietary supplements, and relatively inexpensive. As mentioned above, there are a multitude of fruit and vegetable phytonutrient extracts available that also possess significant antioxidant activity.
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