Popular culture, as reflected in movies, fashion, and literature, is preoccupied with remaining young. A growing anti-aging industry offers myriad products and services to tap into the elusive fountain of youth, with plenty of hucksters and charlatans preying on our dreams. The quest for youth has been with us since antiquity. King Gilgamesh, who ruled parts of Mesopotamia around 3000 B.C., searched for immortality after a close friend died. To accomplish this divine goal, he had to become a half-god, according to Babylonian legend. The first historical record of a treatment to reverse aging is an Egyptian papyrus dated around 1600 B.C. that describes an ointment for regaining youth (without evidence of success or a money-back guarantee). Youth concoctions are still produced and consumed daily, but thus far, the real fountain of youth has come from science and medicine.
Great progress made, much more to come
Mankind made great strides in extending the human life span over millennia (see Figure 1.1). Life expectancy for early humans, including Neanderthals, was painfully short: Half died by the age of 20. In the nineteenth century, life expectancies rose to about 40 years in Western Europe and to 70 years by mid 20th century. These advances were largely the result of treating childhood diseases and conquering infections. Little progress had been made yet in extending the lives of the elderly. For example, American males who managed to reach the age of 70 lived only three years longer at the end of the 20th century than at the beginning of the century. In recent years, however, mankind has extended life for those who reached middle age, ushering in the age of centenarians. Today more than 30,000 people in the United States have passed the magic century milestone. Demographers expect that, in 2020, 300,000 people older than 100 will be living in the United States, with similar tenfold increases projected for centenarians in other developed nations.1 Even though life extensions manifest themselves by people dying at an older age, this can be due to health improvements introduced at the beginning, middle, or end of life. Historically, longer life spans were achieved by focusing on the beginning and middle of life. Today, medicine is making great strides in all phases, but especially the later stages.
Figure 1.1 Average life span in the Western world since ancient times
As shown in Figure 1-2, a 50-year-old woman living in the United States in 1990 could look forward to an average of 31 additional years of life. If we assume a cure for cancer, this increment beyond 50 grows to 34 years; adding a cure for heart disease amounts to 39 extra years. After we conquer stroke and diabetes, the increment rises to 47, yielding a full life expectancy of 97 years.2 No one knows for sure how far we can push the boundary of death, but optimistic scientists consider a life expectancy of 130 years within reach for many young people living today.3 The last bar shows this optimistic projection, which reflects the combined effect of many interventions, including diet and lifestyle changes.
Figure 1.2 Longevity projections
By 2020, new approaches for diseases that presently cause death in the elderly—notably cancer, heart disease, stroke, and diabetes—are expected to increase quality and quantity of life significantly beyond the gains made in the 20th century. Biochips offer much cause for optimism, to monitor our health more closely and eventually deliver medicines in highly customized ways. Stem cells and therapeutic cloning also show promise in regenerating damaged tissue and perhaps entire organs. In addition, new medicines might become widely available for Alzheimer's, Parkinson's, and other degenerative diseases that currently diminish the quality of life for many older people and their families. Although some skeptics in the scientific community believe that we could be reaching the limits of human longevity, other experts believe that many young people in good health today will reach the age of 100 and beyond.4