Biologists have advanced a variety of theories to explain aging, but most of them agree that this process is largely determined by genes. This view is suggested by the great range of lifespans among different animal species—from a few days in the fruit fly to more than 100 years in some tortoises. Scientists have recently learned how to double the lifespans of such laboratory organisms as roundworms and fruit flies through genetic manipulation, and mutant genes in mice have been observed to have a comparable effect in postponing aging.
At the cellular level, an important recent finding has been that the lifespans of cells in the human body are determined by strings of DNA (genetic material) called telomeres, which are located at the ends of the chromosomes. Each time a cell divides, the telomere becomes shorter; the senescence and death of the cell is triggered when the telomere is reduced to a certain critical length. Telomerase, an enzyme that can intervene in this process, is being closely studied in relation to cancer as well as aging.
Environmental factors have been observed to affect aging as well. Scientists have discovered that they can significantly postpone aging in mice by providing them with very low-calorie diets, and recent studies of rhesus monkeys on low-calorie diets appear to be having the same results. It is believed that these diets slow the aging process by lowering the rate at which tissue-damaging substances called free radicals are produced in the body. One aim of these studies is the development of antioxidant drugs that could slow the aging process in humans by protecting against free radicals. The use of testosterone, melatonin, human growth hormone, and other hormones as "anti-aging" treatments is medically unproven and potentially dangerous, as the hormones can have damaging side effects.
See L. Hayflick, How and Why We Age (1994); publications of the National Institute on Aging.
Disorder with characteristics of premature aging. Affected persons have thin skin, go bald or gray early, and develop diseases of aging decades earlier than normal individuals. Not all systems are affected; there is no senility, no aging in the central nervous system. There are two major types. In the extremely rare Hutchinson-Gilford syndrome, children look 60 years old by age 10 and die at an average age of 13. The unrelated Werner syndrome is a recessive hereditary disease that begins in young adulthood and makes patients look 30 years older than they are; their average life span is 47 years.
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Gradual change in an organism that leads to increased risk of weakness, disease, and death. It takes place in a cell, an organ, or the total organism over the entire adult life span of any living thing. There is a decline in biological functions and in ability to adapt to metabolic stress. Changes in organs include the replacement of functional cardiovascular cells with fibrous tissue. Overall effects of aging include reduced immunity, loss of muscle strength, decline in memory and other aspects of cognition, and loss of colour in the hair and elasticity in the skin. In women, the process accelerates after menopause. Seealso gerontology and geriatrics.
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The anti-aging marketplace includes nutrition, physical fitness, skin care, hormone replacements, vitamins, supplements, and herbs. Alternative medicine and holistic approaches have often been an incubator for approaches initially shunned by traditional medicine. Life extension is arguably the most scientifically rigorous part of anti-aging, being a research program focused on slowing down, repairing or reversing the underlying processes of biological senescence in order to deliver improved health and quality of life. (Despite the name, increasing mean or maximum lifespan is not necessarily the main goal).
Leading sources of anti-aging information include the Life Extension Foundation (focusing on research and supplements), the American Academy of Anti-Aging Medicine (focusing on anti-aging physicians and cutting edge treatments), Andrew Weil (focusing on alternative medicine, holistic health, and herbal supplements), the Chopra Center for Wellbeing (focusing on mind-body medicine and integrating Eastern and Western medicine), and the Ageless Lifestyles Institute (focusing on anti-aging psychology). In India, some anti-aging activities are studied by Center for Longevity combining western medical appraoches with Siddha Vaidya nd Ayurveda.
There are many legends of magic places that give life, e.g., Ponce de León’s search for the “Fountain of Youth.” In 1933 British novelist James Hilton’s book Lost Horizon described Shangri-la – an ageless paradise somewhere in the Himalayan mountains near the Tibet-China border. Despite Shangri-la being a fictional place, expeditions have tried to find it.
Gerontologists have tended to paint a bleak picture of aging being all downhill with increasing loss of skills, functions, and quality of life. Women’s movements leaders, e.g., Betty Friedan’s book The Fountain of Youth and books like Gail Sheehy’s Passages helped paint a more positive, generative template for aging.
Around 2000 research started identifying strengths that go with aging. Daniel Mroczek, Ph.D., found that older people report being happier than younger people. At ages 18–27 only 28% reported being very happy. The percentage goes up with each age bracket with the bracket 68-77 at 38%. The rating dips a little at ages 78–89 to 34%. Other researcher found that seniors tend to be better story tellers and become more agreeable and conscientious with age. Laura Carstensen, Ph.D reports that as we age, we are tend to be more positive and in better control of our emotions.
The current documented record holder for longevity was Jeanne Calment, a French woman who lived 122 years and died in 1997. There are reports of older people in some remote villages but there is no documentation to verify the claims (and they live in cultures that give great status to the oldest). Centenarians have become so common, the newest category is “Super Centenarians,” those 110+ years old.
The most definitive research on centenarians is Thomas Perls, MD and Margery’s Living to 100 study of New England centenarians. Interviews with centenarians include Lynn Adler’s Centenarians: The Bonus Years and photographer Liane Enkelis’ incredible photographs and stories in On Being 100. There are quite a few autobiographies and biographies including Jeanne Calment: From Van Gough’s Time to Ours.
Research suggests that centenarians have little in common physically. They are physically active people, most don’t smoke, and they typically maintained about the same body weight through their adult life.
The role of genetics in longevity is complex. A genetic vulnerability to a life threatening disease, e.g., malaria, reduces life expectancy. If a vaccine or cure is developed, the same genes no longer present a problem. With Alzheimer’s disease, for example, those with the certain apo-E gene patterns have a higher risk of developing Alzheimer’s. When scientists develop a cure, Alzheimer’s will no longer compromise the quality and length of life for those who are at risk.
There appear to be genes that foster living longer. Researchers have extended the life of fruit flies by 30% by giving them an extra copy of a gene. Other researchers extended the life of nematodes (microscopic worms) by 500% by removing a gene. It isn’t clear yet why the genetic engineering is extending the lives, but the results are promising.
Danish researchers compared identical and fraternal twins and extrapolated that only 30% of longevity is genetic. That means that 70% is lifestyle and the choices people make. George Valliant, Ph.D., and subsequent researchers have followed Harvard freshman in the classes from 1939–1949 periodically to the present. One especially notable finding was that men who had traits such as optimism and humor as freshmen were less likely to develop chronic illness or die by age 45. The difference was even more pronounced at age 60.
Nutrition has been an extremely controversial area in anti-aging medicine with gurus offering a huge variety of diets to help people stay healthy and live longer. The diets are often contradictory. One of the better validated studies is Dr. Dean Ornish Program for Reducing Heart Disease. Note, however, that the program also places a strong emphasis on exercise, relaxation skills, managing stress, emotional intimacy, and lifestyles. Thus it is not clear to what extent the nutritional program is achieving the results and how big a role the lifestyles components play. One of the few areas of consensus among nutritionists is the importance of keeping stable blood sugar levels, achieved in part by managing the glycemic indexes of food choices.
Some fitness and longevity advocates love grueling sports and activities such as running marathons. This runs the risk of injuries and wear and tear on body parts such as knee joints. Some fitness experts focus on being healthy and fit enough and emphasize a balanced approach. This includes cardiovascular fitness, strength, flexibility, balance, and posture – whether achieved through exercise or sports.
Researchers continue to search for causes and cures for diseases. Tissue engineering is developing ways to grow new tissue, e.g., for burned skin, damaged heart muscle. Tissue engineering includes using stem cells to grow new tissue, organ transplants, and artificial tissue or organs. Nanotechnology, genetic research, and pharmaceutical research are all contributing as well.
Anti-aging medicine has tended to focus on age conscious consumer’s desires to look good, feel good, and live as long as possible. Anti-aging medicine has tended to focus on hormone therapies, supplements, skin care treatments (e.g., skin resurfacing, Botox treatments, Argireline based products), and plastic surgery.
Millions of women have used Premarin (synthetic estrogens and made from mare’s urine) to reduce the impact of menopause. In 1991 the Women’s Health Initiative, studied 161,808 postmenopausal women with randomized trials of hormone supplements vs. placebo. It discontinued the study in 2002 because it concluded that on the whole the supplements were doing more harm than good (primarily due to an increased risk of breast cancer). Suzane Sommers has been championing the use of bioidentical hormone replacement for women as more efficacious. She has received a lot of opposition from doctors.
Millions of men are taking testosterone supplements (usually creams or patches) and tens of thousands of Americans are taking Human Growth Hormone (HGH) injections at a cost of $10–12,000 a year. The Internet has more than a hundred website promoting less expensive secretagogues that claim to prompt the body to naturally produce HGH. There is little independent research on HGH secretagogues.
The U.S. now has more than 5,000 health spas generating $5 billion dollars in revenue. Most are day spas that offer relaxation and beauty treatments. Many are including medical treatments as well.
The Life Extension Foundation, is “the world’s largest organization dedicated to finding scientific methods for addressing disease, aging, and death.” It has focused on vitamins and supplements and much of its income is derived from selling vitamins and supplements. The nonprofit organization conducts and funds anti-aging research. It has a track record of ground breaking results and often being ten years ahead of mainstream medicine in it’s recommendations. It takes a strong advocacy posture and is often critical of the practices of mainstream medicine and pharmaceutical companies.
Andrew Weil, MD is the most prominent leader in alternative medicine, holistic health, and herbal supplements. He gives a balanced approach to optimal health with an emphasis on natural approaches. He is a popular speaker, author, and newsletter editor.
Jack LaLanne is the godfather of physical fitness in the U.S. He says he started the first gym. He had the original fitness program on television, getting millions to exercise with him. He has often celebrated birthdays with prodigious feats such as swimming across a bay while towing dozens of boats. Now in his nineties, LeLanne is still fit, brimming with enthusiasm, and encouraging fitness.
Michael Brickey, Ph.D., is developing anti-aging psychology as a discipline rooted in positive psychology and the psychological factors that promote health and longevity. He focuses on Anti-Aging ABCs – attitudes, beliefs and coping skills. He is a popular speaker, author, and newsletter editor.
Roy L. Walford, MD, a “crew member” of the biosphere experiment, championed caloric restriction as a research validated method for extending longevity. An obstacle to widespread adoption is that most Westerners lack the discipline to choose to limit eating to around 1800 calories a day. Dr. Walford died at age 79. His daughter continues his research.
Rajkumar Reghunathan, MBBS. Believes that ancient techniques for longevity and physical regeneration should be explored scientifically. He is interested in physical regenerative techniques both external and internal, meditation, Siddha & Ayurvedic medicine, yoga, and positive thoughts.