THE PROBLEM OF AGING

Ever since humans began to think and dream sufficiently to inspire fantasies and myths, they have asked several intriguing questions. What causes us to grow old? What, if any thing, can we do to slow this process? How must we proceed to have not only a longer life but a better quality of living, as well?

The only nonaging animal in the world is the sea anemone. It constantly replaces all its cells and is more nearly a culture of multiple organisms rather than a single organism. The rest of us age, but obtaining a precise, all-inclusive definition of aging is difficult. Some doctors who specialize in the problems associated with aging, define aging as progressive accumulation over time of changes responsible for increased susceptibility to disease and, finally, to death, the last event of advancing age. Others define aging as “a progressive deterioration of the organism after maturity of size or function has been reached and which is universal, intrinsic, progressive, and deleterious with time.” THE PROBLEM OF AGING

FREE RADICAL THEORY OF AGING

A major theory of aging research, one that is becoming generally accepted as fact, suggests that free radicals damage body cells. This damage, in turn, causes the pathological changes associated with growing old. Free radical production is related to the body’s use of oxygen. Some of the oxygen in our bodies is converted into water. Usually, this conversion happens immediately. Sometimes, though, the process takes a little longer, and the oxygen can assume very unstable forms called peroxides until the process is completed. These unstable oxygen molecules tends to react with other molecules around them, which can result in severe damage to cells. specifically to the cells’ membranes. Such damage may disrupt various processes within the body. THE PROBLEM OF AGING

While free radicals are normal byproducts of bodily processes and have certain beneficial functions, increased levels of free radicals can permeate the tissues. Such permeation makes them detrimental to one’s health. The products from free radical reactions are implicated in the progressive accumulation of changes over time, which in some individuals may eventually be recognized as disease. Free radical dam- age is now believed to be involved in a number of bodily disorders and diseases, including the two major causes of death, atherosclerosis (a leading precursor of heart disease and stroke) and cancer.

We are exposed to significant sources of free radicals that exist in the environment. Two major environmental sources are the air pollutants nitrogen dioxide and ozone. They are of particular concern for individuals living in heavily polluted areas of the country, such as New York City, Los Ange les (the most air-polluted city in the United States), Boston,

Baltimore, and Atlanta. There are other sources of free radicals. Substances in cigarette smoke cause serious free radical damage in the lungs.

This not only happens to cigarette smokers themselves, but to other people who inhale residual smoke lingering in the air. Heavy metals and halogenated hydrocarbons, present in polluted air and water, cause free radical damage. Free radicals are also produced following exposure to ionizing radiation, as from an X-ray machine or from the atmosphere’s concentrated cosmic and ultraviolet rays that bombard planes in flight. Finally, there is growing evidence that essentially everyone in our society is exposed to free radicals, more now than ever before, because of the hole in the ozone layer. This is a layer of a special type of oxygen in the upper atmosphere that absorbs ultraviolet radiation. Without the ozone layer, more ultraviolet radiation reaches the Earth. THE PROBLEM OF AGING

RESEARCH ON FREE RADICALS

Extensive research on free radicals and aging has been conducted at the University of Nebraska. Early studies by Emeritus Professor of the School of Medicine Denham Harman, M.D., Ph.D., the developer of the free radical theory of pathology, demonstrated that exposure of laboratory animals to radiation appeared to age the animals unusually fast. It caused an increase in free radical levels in their cells.

Increasing the free radical activity in the animals was apparently speeding up the aging process. Other research studies in animals and humans have shown an accumulation of free radical damage in the process of aging or during the development of degenerative diseases.

To study the role of free radical reactions in cellular aging, investigators at Texas A&M University have monitored the effects of vitamin E deficiency in rats. They studied the appearance of a protein in red blood cell membranes that changes shape as the cell ages. Eventually, under normal conditions, the protein displays what is termed by the re searchers as a “senescent cell antigen,” an area of the protein that signals the immune system to destroy the cell. However, among the nutrient deficient rats, red blood cells of all ages behaved like old red blood cells from control animals fed a nutritionally complete diet. THE PROBLEM OF AGING

THE PROBLEM OF AGING