W ith old age comes the associated problems of ageing, cancer, diabetes, arthritis, alzheimers, memory loss, parkinsons, osteoporosis, sarcopenia and other diseases.
Scientists have known for a long time how to extend lifespan. To make laboratory animals live longer, healthier lives, you reduce their calories by 30-40%. Unfortunately it's not a practical solution for most humans, as you constantly feel hungry, cold, and tired.
Kenyon began studying C.elegans, a species of worm with a short life span. The worms live on average 14-18 days, by then the average worms are sluggish, wrinkled and aged. A few days later they will be dead. Her lab searched for an ageing control gene.
After a breakthrough in 1993, researchers discovered the lifespan of C. elegans could be increased by a single gene mutation. They accidentally disabled a single gene – Daf-2 which doubled the worms life-span and also maintained their health. The mutated worms were now living 30-40 days. The worms with a gene mutation stayed healthier right to the end. With more sophisticated genetic manipulation, some worms have lived for 120 days.
Kenyon found out why drastically reduced calories has such a remarkable effect. They discovered that a hormone signaling system controls ageing. Switching off the activity of the DAF-2, then switches on the DAF-16 gene. This extends lifespan and health.
Having extended worms lifespan, further experiments were surprising. She discovered that giving her long-living worms a 10% sugar solution in their water, cut their life by 50%. The mutated worms that had lived 30-40 days, were dying at 18. It shortened their life, by activating the insulin pathway. Worms insulin signalling are similar to humans.
The link between diet and ageing makes sense when you consider the DAF-2 gene, disabled in Kenyon's worms, activates receptors sensitive to insulin and IGF-1, a growth hormone. The DAF-2 receptor is activated by insulin, and sugar in the diet. Worms with a high insulin level age faster. The DAF-2 / DAF-16 genes in the worms, have the same effect in rats, mice and monkeys. As we share our DNA with our primates, the same DNA are active in humans.
Did the research findings influence Kenyon's lifestyle?
Kenyon bought a book on low-carb foods and immediately changed her diet. She stopped eating sugar and carbs after she saw what glucose did to her lab animals. Cutting back on carbs reduces insulin levels.
All carbs stimulate insulin production in the body. Carbs and insulin stop DAF-16, the youth gene, from working. This contradicts health advice since the 70s, to lower fat intake and eat plenty of healthy carbohydrates. Raised insulin levels, triggered by carbohydrate consumption is connected to many western diseases.
Drug companies would love to find a drug to switch off DAF-2 and trigger DAF-16. Can you imagine the market and potential profits?
You don't need to wait for drug companies to find and market a drug. You get the same health benefits by cutting carbs, sugars and starches from your diet.
How good is that?