Cellular Senescence – our cells get old after dividing about 10 to 50 times for humans, depending on cell type, then they change characteristics and function and either commit suicide (apoptosis) or just quit functioning (stasis or senescence). Ultimately it is senescence that defines our maximum life span, thought to be about 120 years for humans.

Several factors can push cells into senescence, but the process is not fully understood, so the known causes may not be the whole story. These include:

  • Stress signals (lifestyle improvement can help)
  • Telomere shortening (nutrition, exercise, supplements can slow this)
  • DNA damage (antioxidants are key)
  • Chromosomal scrambling
  • Oncogenic changes (leading to cancer)
  • Mitochondrial damage (loss of energy production for the cells’ function)

There are, however, known strategies that get the most mileage out of our cellular lifespan. Most of the early studies that laid the groundwork for understanding senescence were done in petre dishes or in vitro, whereas more recent studies are answering the question of whether the same process takes place in live animals or in vivo. The life stages that a cell goes through as it originates from a stem cell through specialization, maturation, multiple divisions, and finally to stasis, senescence or cell death is called the cell cycle.

The process of cell division is called mitosis, and at each division there is an opportunity for DNA to get copied with some errors. Cells make enzymes for DNA repair, wherein some errors can be detected and fixed, but errors do creep in during the life cycle of a cell. If enough errors occur, the cell will enter stasis (reversible under some conditions) or senescence rather than continue to divide. When enough of our cells reach senescence, we have reached ‘old age’. A very important supplement which moderates all six of the above damaging factors is vitamin D. Want to age well? Make sure your blood levels of vitamin D are 70-100ng/ml – get tested and get enough sun or take enough supplemental Vitamin D3 to get to these levels; it takes me 15,000 IU/day to stay in this range.

A key factor in aging is the loss of telomere length with each cell division. Telomeres are likened to the plastic ends of shoelaces that protect them from unraveling. Telomeres are found at the ends of DNA strands in chromosomes, and guard against DNA fusing errors during cell division. Cells that express an enzyme called telomerase can repair their telomere length indefinitely. (All cancer cells manage to turn on telomerase production, thereby managing to stay immortal and divide ceaselessly until they unwisely kill their host). After we reach maturity, our cells turn off the mechanism for making the telomerase enzyme. Early thinking was that if we could just turn on telomerase production in our rapidly dividing cells, we could retard the aging process. However, it seems that telomere shortening is a tradeoff against the risk of developing enough errors to allow the development of cancer.

Another key cause for senescence is loss of mitochondrial function. These little energy factories stop dividing, puff up a bit and stop making energy when they acquire enough damage from their normal metabolic function of making ATP molecules to power our cellular activities. When a cell divides, its mitochondria pull in toward the nucleus and divide to roughly double their number, and then about half go on with each daughter cell. They also multiply within individual cells to meet energy demands – exercise causes them to multiply, and more is better. Mitochondria have their own DNA, which has repair mechanisms to fix DNA copying errors, but they are not as skilful as those that repair nuclear DNA. CoQ10 is a key protector of mitochondrial DNA.

So what strategies are known to be effective in keeping cells clocking along doing their job effectively? Here are the bottom line strategies and why they seem to work:

Caloric Restriction - turns on longevity genes that keep cells functioning well longer. One of the following articles supports my belief that the primary factor in caloric restriction is actually restriction of glucose and other dietary sugars and starches. Our bodies work best if about 65% of our energy production results from burning fats as our primary fuel. This goes right along with the Leptin Diet strategy that I have been using and promoting for the last few years. If you want to shorten your healthy life span, just eat too much too often

Resveratrol and Quercetin - activate most of the same genes as caloric restriction. Anyone wanting to live long and healthy will do well to supplement significant amounts of these. I’m taking 250 mg of resveratrol – click to see why and 1500 mg of quercetin daily.

Exercise - yes, there is that all-important word we love to hate, but a recent study showed that intense endurance muscular activity turns on telomerase production in muscle cells, prolonging the functional life of our muscles. Exercise is critical to staying strong into advanced age – use it or lose it - a fundamental truth! This study only looked at distance runners, but my bet is that strength training will have exactly the same benefit.

Lowering Inflammation - Inflammation generally increases the rate of telomere loss and DNA damage, and at the same time causes damage to mitochondria, all of which pushes cells toward earlier senescence. Supplements described for Inflammation in Part 4 of this series will be important for this aspect of aging.

Astrogalus - TAT2, a compound in astrogalus root, used in Chinese herbal therapy, prolongs killer T-cells' ability to divide because it ramps up telomerase in these and possibly other cells. The company TA-Sciences makes a modified extract of Astrogalus called TA-65 that they show brings rapid reversal of most markers of aging. Check out their website here: http://www.tasciences.com/ta-65/. If you have an extra $5000 lying around to try it for a year (they suggest a 4 year course of treatment), the results shown to date are pretty remarkable. For doing this from home, Dr Al Sears provides a self-run program: You can lengthen your telomeres and live better longer according to Dr. Sears.

Yes, we all wear out and eventually die – but for me, later is better. I have lots of fun in this life and having good health is a profound blessing I hope to sustain as long as practical.

Good Living - Frank

Author's Bio: 

Frank Wilhelmi of http://www.seniorfitness.com chronicles strategies for staying healthy and fit into advanced age. He is an electronic engineer by trade, but his passion is teaching others to lead healthy, vibrant, pain-free, activity-filled lives.