Читать книгу Aging - Harry R. Moody - Страница 76

Free radicals are unstable organic molecules that appear as a by-product of oxygen metabolism in cells (Armstrong et al., 1984). Free radicals are highly reactive and toxic when they come in contact with other cell structures, thus generating biologically abnormal molecules. The result may be mutations, damage to cell membranes, or damage by cross-linkage in collagen.

Free-radical damage has been related to many syndromes linked with aging, such as Alzheimer’s disease, Parkinson’s disease, cancer, stroke, heart disease, and arthritis. According to the free-radical theory of aging, damage created by free radicals eventually gives rise to the symptoms often associated with aging.

An important point about this theory is the fact that the body itself produces so-called antioxidant substances as a protection against free radicals. These antioxidants scavenge or destroy free radicals and thus prevent some of the damage to cell structures. The production of antioxidants is, in fact, correlated with the life span of many mammals.

Free-radical theory has prompted some observers to believe that consuming antioxidant substances, such as vitamin E, might slow down the process of aging. Genetic engineering techniques can now be used to produce antioxidants in vast quantities, but antioxidants are also supplied by the food we eat. Vitamins A, C, and E, as well as less familiar enzymes, play a role as antioxidants. Animal studies to date, however, show that consumption of antioxidants produces only minimal effects on aging.

Biologists recognize the importance of diet in longevity. It turns out that the dramatic doubling of human longevity, compared with other primates, could be understood in terms of inflammation. Inflammatory processes appear to have a role in conditions such atherosclerosis (buildup of plaques in arteries), Alzheimer’s, cancer, and diabetes. Gains in longevity may be understood in terms of reduced levels of inflammation. For that reason, an anti-inflammatory diet is the subject of important research today (Finch, 2007).