The key is not what you expect…
When we hear about people who live to age 100 or beyond, it may seem like a relatively rare occurrence. But in fact, the number of those “super agers” is dramatically increasing—in 1980, 15,000 Americans had reached the centenarian milestone…by 2014, their numbers had increased to more than 72,000. Overall, the life span of the average American has increased by more than 60% in the last century. Some experts believe that’s just the beginning.
To learn more, Bottom Line Health spoke with Michael Fossel, MD, PhD, a leading expert on aging who believes that both aging and chronic diseases can be slowed by “switching on” a gene that controls cellular health.
Are medical and social improvements responsible for longer average life spans in the US?
They’ve certainly helped. We can now cure many childhood leukemias and treat diabetes and most infections. We are now less likely to experience malnutrition or hygiene-related diseases than we were a century ago—due, for example, to better agriculture and safer water supplies.
But these factors mainly affect the risk of dying young (or younger than you’d like). They don’t guarantee that you’ll live an extra-long life.
How much does one’s lifestyle affect life span?
Less than you’d think. Consider diet. Most people assume that a good diet is the secret to a long and healthy life. But research has failed to find a consistent link. When scientists interview centenarians, they find that their dietary habits are all over the map.
I’m not suggesting that diet doesn’t matter. Many well-regarded studies—such as the Framingham Heart Study and the Nurses’ Health Study—have shown that diet makes some difference. People who eat a lot of saturated and trans fats tend to get more heart disease and die younger…and those who sip a little red wine tend to be healthier.
But there’s a ceiling effect. People who eat a reasonably good diet are more likely to live longer than those who eat poorly. There’s just no definitive evidence that going from a reasonably healthful diet to a great diet will help you slow the aging process or stop age-related disease.
Don’t people who exercise live longer?
Yes. Studies show that people who exercise tend to live longer. But does the exercise itself get the credit? Or do these people simply have “healthy” genes that make them feel good and want to exercise? Correlation is not necessarily causation. Whileproving that exercise is good for you isn’t as easy as you might think, it is certainly hard to argue against its value. I definitely encourage exercise.
But all our habits are mediated, in part, by how our bodies respond. The cells of young people generally have robust repair mechanisms that can mitigate damage caused by unhealthy behaviors. In older adults, the cells are less capable of self-repair—and that’s when diseases get serious. While genes, diet and exercise play a small role, the major factor is still cellular aging.
Does cellular self-repair—or the lack of it—affect aging?
Generally speaking, genetic damage occurs when cells divide. With each division, for example, telomeres (caps on the tips of each strand of DNA on your chromosomes—often compared to plastic tips on the ends of shoelaces) get slightly shorter.
Why it matters:
Every shortening of the telomeres changes gene expression, the ability of genes to produce the proteins and other substances that maintain life—and that allow cells to repair themselves.
How does this affect life span?
Every disease is caused in part by cellular breakdowns. Why do young people get fewer chronic diseases? Because their cells can readily recover from infections, inflammation and other “insults.” Older cells, with their shortened telomeres and altered gene expression, aren’t as resilient, and DNA repair, for example, slows down. This is why the risk for cancer, for instance, goes up exponentially with age.
Is it possible to prevent telomere shortening?
In lab and animal studies, scientists have already found ways to “reset” telomeres to their original length. The evidence suggests that doing so could help people live longer, healthier lives.
The key to this process: Every cell in the body contains a gene for telomerase, an enzyme that lengthens telomeres. However, the gene only “turns on” in germ and stem cells (which can repair/divide indefinitely). Activating this gene in other cells could possibly do the same thing.
In studies, lengthening telomeres has been shown to improve immune function, blood pressure, bone density and other “biomarkers” for aging and age-related diseases. Now we need a mechanism to reliably use this process in humans.
Can We Slow Aging?
Over-the-counter supplements known as telomerase activators are designed to help maintain and rebuild telomeres (caps at the end of each strand of DNA in our chromosomes, which help prevent deterioration of these gene-encoded structures). The supplements, available online, seem to improve some biomarkers of disease (such as cholesterol). Will this type of supplement help people live longer? There’s no proof yet. Many experts on aging believe that the supplements may be somewhat helpful—although likely much less effective as they would need to be to prevent/cure age-related diseases. And they’re expensive, costing several hundred dollars a month.
In the future: It may be possible to deliver an “active” telomerase gene directly to the body’s cells. In theory, this could potentially prevent and even cure many—if not most—age-related diseases. While you could still die of trauma, infections, inherited genetic problems and other causes, we could essentially halt most “age-related” diseases, such as atherosclerosis, Alzheimer’s, osteoarthritis, etc. You might have the health of a 30- or 40-year-old and could easily live to twice the current healthy life span.