ABSTRACT
Never before in human history has so much been known about our bodies and the genetic, molecular, and physiologic mechanisms that dictate their function. Never before, have so many humans lived longer, with the percentage of Americans aged 65 and older (65+) rising from 4% in l900 to 13% in l990, an increase that is even higher in the population of other countries (Chapter 2). Yet, little is known about why we become old. It is predicted that by the year 2030, approximately one-fifth (18%) of the population of the United States will live 65 years and longer. Such impressive and persistent increase in the elderly (65+) population underlies the pressing need for a better understanding of the aging process and the problems of the elderly. Among the challenges that greet the beginning of the
21st century is how we can maintain good health and postpone or reverse aging along with its debilitating diseases. In other words, how can we preserve youthfulness in later life?
