Calorie Restriction
- The Theory: Much of the damage due to aging in the body is caused by the metabolic process of converting food into energy. If we can limit the amount of food by 30 to 50 percent, then we can limit the damage due to aging.
- The Evidence: Pretty good. Researchers have been able to almost double the life span of rats in the laboratory through a 30 to 50 percent calorie restricted diet. Studies have also been done successfully in primates that extend life somewhat and prevent many age-related illnesses. No studies have been completed in humans, though there are people who are attempting a calorie-restricted diet. Time will tell if they live longer than average.
Nutritional Approaches
- The Theory: Supplying the body with more antioxidants and other nutritional elements will help to slow the process of aging. By giving the body more antioxidants, damage by free radicals is lessened.
- The Evidence: It is not clear whether these approaches slow the actual aging process, or merely reduce an individual’s risk of illness. No studies have linked these nutritional approaches with an actual increase in life span though they are linked with a decrease in illness. Supplements have been shown not as effective as eating real food. The oldest advice is still the best advice: Eat Lots of Fruits and Vegetables.
Hormone Replacement Therapy
- The Theory: As people age, their levels of hormones, especially human growth hormone, testosterone and DHEA, all decline. Hormone replacement therapy gives people doses of these hormones to counteract the effects and impact of aging.
- The Evidence: A person taking some hormone replacement therapy will feel better for a time. But the supplements are likely to slow down, not speed up, the body’s own ability to make these important hormones. No evidence exists to link hormone replacement therapy with increased life span in humans.
Body Part Replacement
- The Theory: The human body is like a house, over time, you can replace the roof, change the doors and ever redo the kitchen but the house itself survives. Adherents to this theory believe that through human cloning, stem cell research and other new technologies, we will be able to grow and replace body parts as they wear out.
- The Evidence: We can expect more body part replacement in the future, but this approach is unlikely to counteract aging itself. The wear and tear theory of aging that is behind the logic of body part replacement does not take into account the systemic changes that occur over time.
Cryonics
- The Theory: If you can stop your life’s clock from ticking in an ageless state of suspended animation, then you can wait for new technologies to come along to cure illnesses, replace your organs and keep you living. Cryonics adherents believe that by reducing body temperature in a complex process that prevents freezing but chills the body to extremely low temperatures, one can preserve cells and tissues indefinitely.
- The Evidence: Very little evidence exists to suggest that cryonics works. No mammal has ever been successful cryo-preserved and brought back to life. The standard practice with humans is to place a person in a cryogenic state immediately upon death, but before the degeneration of tissues and cells. This is done in the hopes that someday in the future, medicine will not only be able to revive a person from this state, but also be able to treat whatever caused death in the first place.
Sources:
Ray Kurzweil and Terry Grossman. Fantastic Voyage: Live Long Enough to Live Forever. Plume, 2005.
Brain Delaney and Lisa Walford. The Longevity Diet
