Ask A Scientist
Why do we age?
Asked by: John Kenny
School: St. John the Evangelist School
Teacher: Anu Rai
Career Interest: Movie reviewer
Answer from Lina Begdache
Research Assistant Professor, Binghamton University
Research area: Obesity, GERD, nutrigenomics Interests/hobbies: running, reading
"Why do we age?" is a question asked by many, including scientists. Knowing why and how we age might lead to the development of anti-aging therapies. Aging could be divided into chronological aging, which is related to our biological clock, and premature aging due to unhealthy lifestyle and diets, which accelerate the process of aging. In order to understand why we age, we need to take a closer look at the human body, which is made of trillions of cells. These cells come together to produce tissues, organs and organ systems. Thus, when our cells age, our organ function declines, which is the hallmark of aging.
Cells have genetic materials packaged in the form of chromosomes, which carry our genes. As we grow or repair body tissues, our cells divide to make new daughter cells. Therefore, chromosomes divide as well (or replicate) when new cells are made. As chromosomes replicate, their ends (called telomeres) start to shorten. Telomeres protect chromosomes from losing genetic material. When telomeres reach a certain length, cells stop dividing and enter a stage of senescence (in other words, cellular aging). Therefore, our biological clock depends on telomere length at birth. Studies on longevity have shown that populations that have longer life spans tend to have longer telomeres than others.
Aging could be accelerated by a poor diet and an unhealthy lifestyle. Our body constantly produces toxic oxygen molecules called free radicals, which cause oxidation of cell components. Lack of anti-oxidants in our diet promotes oxidation, which eventually kills our cells. Neighboring cells divide to replace dead cells, which, as we just learned, causes shortening of telomeres and accelerates cellular senescence. Anti-oxidants are mostly found in natural foods, such as fruits and vegetables, tea and dark chocolate. Other lifestyle factors that promote cellular oxidation include smoking, UV rays (from the sun and tanning booths), x-rays, pollution, stress and lack of physical activity.
While we can’t do much to change our genetic make-up, we can slow down cellular aging by leading a healthy lifestyle and eating a nutritious diet.
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