ANSWER : Both DNA and lifestyle can affect longevity, and they both do so in the same way: by altering our body chemistry. DNA controls the production of each of the natural chemicals in our body. It controls both the shape (and, hence, the effectiveness) of each chemical, and also controls how much of that chemical is made.
So, it’s not surprising that DNA could affect longevity. In the past 20 years, astonishing progress has been made in understanding the body chemistry that controls the aging process. And that knowledge has allowed scientists to extend the life of various animals through simple genetic manipulations.
Most of us want to live as long as we can, but we want to do so free of diseases. Living longer is one thing; prolonging decrepitude is another. A recent study from Harvard Medical School suggests that genes associated with longer life may also protect against age-related diseases. The scientists created a virus that carried three “longevity genes” into mice — a technique called gene therapy.
They found that these longevity genes also protected the mice from (1) becoming obese, even when fed a high-fat diet; (2) developing the mouse equivalents of type 2 diabetes and heart failure; and (3) suffering a particular kind of kidney failure.
Things that work in mice don’t always work in people.
But this study suggests it may someday be possible to use gene therapy not only to prolong life, but also to prevent some age-related diseases.
As for lifestyle, we have a pretty good understanding of what a healthy diet is, and how a healthy diet changes our body chemistry in a beneficial way. We also understand quite well how certain unhealthy lifestyle habits — for example, smoking or alcohol abuse — adversely affect our body chemistry.
In contrast, we are only beginning to understand how exercise affects body chemistry. One way of learning about our chemistry is to study it in animals, even very simple animals. One recent study focused on a worm. Over the past 40 years, many lessons learned from this little worm have proved true in humans.
The recent study found that when worms exercise regularly (but not too much) early in life, their metabolism improves, their muscles and guts function better throughout life, they live longer, and they are protected against the worm version of Alzheimer’s disease. Now, scientists will try to unravel what changes in the worm’s body chemistry may cause these benefits.
So, both DNA and lifestyle affect longevity, and as we learn more about how they do that, we may someday increase our healthy life span.
