by S. Todd Stolp MD
©March 2008
Seeking an antidote for aging has been a dream of humans since before Ponce de León searched in vain for the Fountain of Youth in Florida, followed centuries later by hordes of retirees from New York. In fact, led by advances in sanitation, housing, and subsequently by the vaccination and antibiotic era, humans have enjoyed a fair amount of success by increasing life expectancy from 47 years to about 80 years over the past 150 years in developed nations. While it is unfortunate that these successes have not generally been shared with countries left behind by modern advances, the World Health Organization and certain private foundations are currently seeking to more evenly distribute these achievements. The challenge facing developed countries, in addition to helping to correct the disparity in public health resources between the wealthy and poor, is to continue to increase longevity while at the same time assuring that this increased quantity of time includes the promise of quality of life. The fields of research are studded with disappointments, but also with some exciting new discoveries.
There have been several recognized changes in cells that occur as we age. Many of these changes have been attributed to damage resulting from byproducts of the operations of our cellular machinery. We know that a particular “handle” on our DNA, called the “telomere,” seems to shorten as a cell divides over and over again, leading eventually to cellular death. We know that exposure to certain unstable molecules within the cell causes damage to cellular materials by oxidation, and thereby lead to shortened cellular life span. This contributed to a search for “antioxidants” as a solution to aging, and resulted in the emergence of many advocates of mega-doses of certain vitamins. However, recent research has not confirmed the promised benefits of high dose Vitamin E and Beta carotene supplementation. While a number of genetic markers have been recognized as promoting longevity, the practical application of this knowledge to public health is only theoretical.
On the other hand, there are reasons for some hopeful optimism in this quest for longevity. Work done in 2006 with the fruit fly and certain worms uncovered an enzyme system which not only extends life span, but also reduces the frequency of several diseases of aging, such as type 2 diabetes. A search is underway for other molecules that stimulate the “sirtuin” enzyme system and several candidates have come to light, but much research is needed before any conclusions can be practically applied to humans.
Through research done with rhesus monkeys and other species, one intervention has been repeatedly demonstrated to have a positive impact on longevity. Animals that consume a calorie-restricted diet live longer. It is in keeping with Nature’s sense of humor that exactly the behavior most averse to affluent populations is the behavior which appears to have the greatest impact on increasing life span. While solutions other than limiting food intake are being sought to extend lifespan, for the time being calorie restriction appears to be the most accessible option, if not the most marketable.
While these thoughts have not addressed the critical issue of quality of life, it is important that we flavor any increased duration of life with satisfaction. We are again left with the task of deciding for ourselves what balance between time and quality provides us with the rewards we seek.