Telomeres: A Hallmark of Aging
One of the central mechanisms responsible for the aging of cells is the shortening of telomeres.
What are Telomeres
Telomeres are repetitive DNA sequences at the end of chromosomes which act as protective caps. Chromosomes are located within the nuclei of your cells and carries part or all of your DNA as specific genetic information. As the cells in your body divide, your chromosomes need to replicate so that each cell contains a complete set of chromosomes in its nucleus. Cell division is necessary for growing new skin, blood, bones and other cells. And these new cells are constantly renewing essential body tissues and organs.
During cell division, telomeres keep chromosome ends from unraveling and sticking to each other, which would destroy or scramble an organism's genetic information. Without telomeres cell division could malfunction causing inactive or "senescent” cells, cancer or cell death. Yet with each cell division, small pieces of the telomeres are trimmed off, shortening the telomeres
until they can no longer divide. Luckily, we have an enzyme called telomerase which can actually replenish worn down telomeres, creating length.
But just as telomeres are subject to oxidative stress so is the enzyme telomerase. Oxidative stress will reduce the amount of available telomerase which means that cells will not be able to continue to divide and damage cells build-up increasing age related disease.
This maintenance of cellular health is why telomerase is viewed as an anti-aging enzyme.
The 2009 Nobel Prize in Physiology or Medicine was awarded to Elizabeth Blackburn, Carol Greider and Jack Szostak for “the discovery of how chromosomes are protected by telomeres and the enzyme telomerase “.
But before thinking about adding telomerase to your anti-aging regimen, consider how this enzyme works. Too much telomerase can increase growth of cells and thus increase the risk of cancer, yet too little telomerase can also increase cancer by reducing the healthy regenerative and division of cells which keeps the body healthy.
An ideal level of telomerase and telomere length is best accomplished by reducing oxidative stress which damages cells. If our cells are exposed to a lot of stress and injury – even at a young age – then they are forced to divide more often to try and restore health and which will shorten their telomeres.
Telomere length is influenced mainly by oxidative stress which causes damage to DNA, proteins and lipids. These oxidants are highly reactive substances that result from inflammation, infection and toxins.
The following create oxidative stress and have been documented as shortening telomeres.
Inactivity. An NHANES study revealed that those who engaged in high levels of physical activity had significantly increased telomere length compared to sedentary individuals.
Obesity. Obesity is related to high levels of oxidative stress which increases DNA damage and the rate of telomere shortening.
Nutrition. Diets rich in antioxidants can decrease oxidative stress by increasing antioxidant activity in your body which protects DNA. Refined carbs, sugars and processed foods create oxidative stress.
Glycation. This happens when glucose, the main sugar we use as energy binds to our DNA, proteins and lipids, leaving them unable to do their jobs. Accumulation of glycation over the years leads to tissue damage resulting in disease.
Stress. Several very important studies have been done looking at the effects of psychological, chronic and life stress affecting telomere length.
Toxins. Environmental toxins, smoking and alcohol all increase oxidative damage and inflammation.
Genetics. Genetic factors contribute about 30% of an individual’s telomere length. Environmental factors play a much great role on cellular health and aging.