Can Medical Science Help?

Science magazine noted: “Life expectancy at birth [in the United States] has increased from 47 years in 1900 to about 75 years in 1988.” As a result of reducing the infant death rate through better health care and nutrition, people in the United States can now expect to live about as long as Moses stated. Nonetheless, are any dramatic increases anticipated in how long most people live?

Significantly, Leonard Hayflick, a leading authority on aging, said in his book How and Why We Age: “Advances in biomedical research and the implementation of improved medical care in this century have certainly had an impact on human longevity, but only by allowing more people to approach the fixed upper limit of the human life span.” So he explained: “Life expectation has increased but life span has not; the distinction is critical.”

What is the “fixed upper limit” of man’s life span? Some say it is uncertain that anyone in recent times has lived beyond the age of 115. Yet, Science magazine said: “As of 1990, the oldest verified age that an individual has survived is just over 120 years.” And early this year the French minister of health, along with droves of reporters and photographers, visited Jeanne Calment of Arles, France, to mark her 120th birthday. Moses too lived to the age of 120, far beyond the norm.​—Deuteronomy 34:7.

Do scientists hold out hope that people may commonly live that long or longer? No, most do not. A headline in the Detroit News read: “Researchers Say 85 May Be the Outer Limit of Average Lifespan.” In the article a recognized authority on aging, S. Jay Olshansky, said: “Once you go beyond the age of 85, people die from multiple-​organ failure. They stop breathing. Basically, they die of old age. And there’s no cure for that.” He added: “Barring a reversal of human aging on a molecular level, the rapid increases in life expectancy are over.”

Science magazine noted that perhaps “the upper limit to longevity has already been approached and that further significant declines in mortality are unlikely.” It is said that if all causes of death reported on death certificates could be eliminated, life expectancy would be increased less than 20 years.

Thus, many scientists view the length of man’s life span as neither strange nor subject to change.

Designed to Repair Itself

Writing in the magazine Natural History, biologist Austad presented the common view: “We tend to think of ourselves and other animals in the same way we think of machines: wearing out is simply inevitable.” But this is not true. “Biological organisms are fundamentally different from machines,” Austad said. “They are self-​repairing: wounds heal, bones mend, illness passes.”

Thus, the intriguing question, Why do we age? As Austad asked: “Why, then, should [biological organisms] be subject to the same sorts of wear and tear as machines?” Since bodily tissues replace themselves, couldn’t they continue to do that forever?

In Discover magazine, evolutionary biologist Jared Diamond discussed the marvelous capacity of physical organisms to repair themselves. He wrote: “The most visible example of damage control applied to our bodies is wound healing, by which we repair damage to our skin. Many animals can achieve much more spectacular results than we can: lizards can regenerate severed tails, starfish and crabs their limbs, sea cucumbers their intestines.”

Concerning replacement of teeth, Diamond stated: “Humans grow two sets, elephants six sets, and sharks an indefinite number during their lifetime.” He then explained: “Regular replacement also goes on at a microscopic level. We replace the cells lining our intestine once every few days, those lining the urinary bladder once every two months, and our red blood cells once every four months.

“At the molecular level our protein molecules are subject to continuous turnover at a rate characteristic of each particular protein; we thereby avoid the accumulation of damaged molecules. Hence if you compare your beloved’s appearance today with that of a month ago, he or she may look the same, but many of the individual molecules forming that beloved body are different. While all the king’s horses and men couldn’t put Humpty Dumpty together again, nature is taking us apart and putting us back together every day.”

Most cells of the body are periodically replaced by newly formed ones. But some cells, such as brain neurons, may never be replaced. However, Hayflick explained: “If the cell has had every part replaced it is not the same old cell. The neurons you were born with might appear today to be the same cells, but in reality many of the molecules that composed them when you were born . . . may have been replaced with new molecules. So nondividing cells may not be the same cells you were born with after all!” This is because the components of the cells are replaced. Thus, replacement of body materials theoretically could keep us alive forever!