The phrase “age is just a number” is bandied about by everyone from fitness gurus to life coaches, but there is an undeniable element of truth to the tired cliché. Men and women in their 90s and 100s running marathons to completion, a 95-year-old practicing yoga teacher twisting her body in knots, an 88-year-old gymnast who can hover horizontally from a set of parallel bars using only her arms—such individuals may not be the norm, but their existence begs the question: Why do some of us age faster than others?
Genes, diet and physical activity all undoubtedly play a role in determining whether we’ll need a walker at 75 or still be able to run a 5k every day. But are there other overlooked factors that are accelerating our aging process?
Yes there are, according to a recently published paper in the journal “Trends in Molecular Medicine.” A trio of experts from the University of North Carolina (UNC), Norman Sharpless, Jessica Sorrentino and Hanna Sanoff claim that some of the major contributors to aging—dubbed “gerontogens”—can be found in our everyday environment.
- Cigarette smoke: No surprises here. With 4,000 potential toxicants, cigarette smoke has been linked to a host of health problems—from cancer to heart disease to arthritis. Studies have also shown that those who smoke regularly are chopping an average of seven years off of their lifespan. When it comes to speeding up the aging process, smoking damages DNA and shortens telomeres, important chromosomal components that impact how rapidly cells age. Regular cigarette use also increases wrinkling of the skin by constricting blood vessels, and degrading collagen and elastin.
- Ultraviolet light: Another unsurprising enemy of youth, UV light exposure is known to contribute to DNA mutation, photoaging and skin cancer.
- Benzene: One of the top 20 most widely-used chemicals in the U.S., benzene is used to make a variety of different lubricants, dyes, plastics, drugs and pesticides. It can be found in tobacco smoke, industrial emissions and car exhaust. Excessive benzene exposure can shorten telomeres, and contribute to the development of certain cancers including lymphoma and leukemia.
- Arsenic: A chemical that inhibits the ability of DNA to repair itself, arsenic is used to make certain herbicides, insecticides and pesticides. It also can be found in small amounts in water, rice, seafood and certain agricultural products, though the FDA has taken steps to monitor and regulate arsenic levels in the food supply. A known carcinogen, arsenic can be fatal in high doses, though not much is known about the long-term effects of low-level arsenic exposure.
Though not found in the everyday lives of most individuals, chemotherapy has also been identified as a gerontogen. While the other toxins on the list have been shown to contribute to the development of cancer in some way, the chemotherapy drugs used to treat cancer can also accelerate aging, mainly by damaging DNA structures and other healthy cells. Chemotherapy helps combat cancer by inhibiting the ability of malignant cells to grow and divide. Unfortunately, the chemicals also attack benign cells, often resulting in hair and appetite loss, fertility issues, and a number of other side effects.
When discussing chemotherapy’s role in the aging process, study authors acknowledge its essential role in the cancer treatment process, but emphasize the importance of developing a more well-defined method for accurately weighing the physical costs of chemo against the benefits.
At this time, the connection between the aforementioned environmental toxins and the aging process is known but not well understood, which is why Sharpless and his colleagues urge further investigation into the issue. “We believe just as an understanding of carcinogens has informed cancer biology, so will an understanding of gerontogens benefit the study of aging,” says Sharpless in a UNC press release. “By identifying and avoiding gerontogens, we will be able to influence aging and life expectancy at a public health level.”