Merck Manual of Health & Aging

Age-Old Questions Aging begins the moment a person is born. A baby develops and matures into an adult. Then, at some point, the aging process changes. The person begins a decline in function that ultimately leads to deathwhat people usually think of as aging or growing old. The technical term for this decline in function that ends in death is "senescence." Science can provide information about changes in the body that lead to aging and death. Science can determine how some of the changes occur. But two basic mysteries remain: whether aging and dying have a purpose and, if so, what that purpose is. Throughout history, people have responded to these mysteries by searching for a "fountain of youth" that will prolong the time spent as vigorous, healthy young adults. And the search continues as researchers look for ways to slow or reverse the aging process. Some progress has been made in the search. During the last century, life expectancy for people in the United States has greatly increased. As a result, what people consider to be old age has changed dramatically. Improvements in life expectancy occurred in two stages. First, death during childhood has become less likely, largely because sanitation has improved and because vaccines and treatments for childhood diseases, such as antibiotics, were developed. Second, disease and disability have become less likely to develop or have been postponed in older people because health care and approaches to prevention have improved. In spite of these improvements, even the healthiest and luckiest people do not live beyond about age 130. Looking for the Fountain of Youth Books about how to stay young and live longer abound. Almost everyone is interested in living a long life and looking and feeling young. No Ponce de Leons are traveling to new lands on a search for a magic fountain to restore their youth. However, researchers are looking at genes, cells, hormones, eating patterns, and other factors for clues about what causes aging and how to prevent or slow it. Research has identified three strategies that may help people live longer: exercising, following certain types of diets, and eating fewer calories. People who exercise are healthier than those who do not. Exercise has many established health benefits: improving and maintaining the ability to function, maintaining a healthy weight, and helping prevent or postpone disorders such as coronary artery disease and diabetes. People who eat a low-fat diet that includes lots of fruits and vegetables are healthier than people who eat more fat and starch. Also, people who live in Mediterranean countries and consume the so-called Mediterranean diet seem to live longer. This diet is generally thought to be healthier than northern European and American diets because it consists of more grains, fruits, vegetables, legumes, nuts, and fish and less red meat. In addition, the main fat consumed is olive oil. Olive oil contains many vitamins and consists mainly of monounsaturated fat rather than saturated fat. Monounsaturated fats do not increase cholesterol the way saturated fats do. A low-calorie diet over a lifetime may lead to longer life because it reduces the number of certain damaging substances in the body. These substances, called free radicals, are by-products of the normal activity of cells. The damage done to cells by free radicals is thought to contribute to aging and to disorders such as coronary artery disease and cancer. But no studies to test this theory have been done in people. These three strategies would require a change in lifestyle for most people. Consequently, many people look for other, less demanding ways to prevent or slow aging. For example, they may look for other ways to manage free radicals. Substances called antioxidants can neutralizeBeers, Mark H. is the author of 'Merck Manual of Health & Aging ', published 2005 under ISBN 9780345482754 and ISBN 0345482751.