Most organisms have a molecular clock which sets the lifespan of cells. The number of times a cell population can divide is called the Hayflick limit, after which the cells undergo “apoptosis” (programmed cell death). Apoptosis is otherwise triggered by the body’s inner and outer environment (stress, UV light, pollution..). People in their 80s and 90s have a Hayflick limit of 20 divisions compared to younger people who have around 50. Telomere shortening in humans eventually makes cell division impossible, and this aging of the cell population appears to correlate with the overall physical aging of the human body. Maximum life span in humans is currently approximately 125 years.
Here are a few reasons why cells deteriorate and die:
When telomeres are depleted after a number of cell divisions.
Proposed solution : The enzyme telomerase contains an RNA template capable of producing new telomeres on the ends of aging cells. Cancer cells, stem cells and sperm and eggs can divide indefinitely because they express telomerase. If telomerase is added to a cell it will replicate beyond the Hayflick limit. TA-65, an (expensive) prescription drug from the astragalus root, adds telomerase to the cell.
When the cell accumulates too much waste.
Proposed solution : Calorie restriction with sufficient nutrients is at the moment the only scientifically proven way of lengthening life in mammals, since it restricts damage caused by metabolising food.
Free radicals, which are negatively charged molecules, break up pairs of molecules to steal their positively charged partners, attacking the cell membrane, collagen and elastin.
Proposed solution : Vitamins and minerals are free radical ‘scavengers’ and can slow aging.
There is a genetic code within our DNA that is programmed to self-destruct after a number of years.
Proposed solution : When scientists silenced a gene called IGF-1 in mice organs life span was extended by up to 33%; calorie intake stimulates IGF-1.
Hormone depletion causes a decline in the body’s ability to repair itself.
Proposed solution : Hormone replacement therapy.
Wear and tear damages cells. Just using our organs wears them out like any machine component and serious abuse will hasten the end.
Proposed solution : Nutrients and clean living.
Biological immortality is not impossible. There are a few creatures, such as the hydra and the turtiopsis dohrii jellyfish, which maintain telomere lengths; lobsters also show no signs of aging, becoming increasingly fertile throughout their lives.
Nature has therefore allowed for a small window of “negligeable senescence”. Keep reading these blogs for more ways of staying ageless.