Book review:
Lifespan: Why We Age, and Why We Don’t Have To
by David A. Sinclair Ph.D.
David Sinclair Ph.D. AO is a Professor of Genetics at Harvard Medical School. He is an innovator and recognised by TIME magazine as ‘one of the 100 most influential people in the world.’
In a chapter called the Blind Epidemic, Sinclair talks about the growing worldwide problem of diabetes. During WWI, French biophysicist Pierre Lecomte du Noüy noticed a difference in the healing rate of wounds between young and old soldiers. A child will heal from a foot injury with little more than a Band-Aid. For an elderly person, a foot injury can be dangerous. And for diabetics, the story is much worse.
“The five-year mortality rate for a foot ulcer in a diabetic is greater than 50 per cent. That’s higher than the death rate for many cancers.”
Sinclair argues that instead of putting diabetes as among the deadliest diseases afflicting humanity, medical science labels it a “loss of resilience.” They accept it as part of getting old and dying.
David Sinclair. Ph.D. is a scientist at the Harvard School of Medicine. This is what he says about aging: “Once you recognize that there are universal regulators of aging… with a molecule such as NMN or few hours of vigorous exercise, or a few less meal: Aging is going to be remarkably easy to tackle. Easier than cancer.” But what does it all mean to the layperson?
Sinclair uses acronyms such as NMN as though everyone will understand. NMN stands for nicotinamide mononucleotide, a molecule naturally occurring in all life forms. At the molecular level, it is a ribonucleotide, which is a basic structural unit of the nucleic acid RNA (perhaps NMN is so commonly known, its inclusion into the glossary was unnecessary).
Sinclair’s claim sounds attractive, but it is hard to ignore initial scepticism. If vigorous exercise meant aging is easier to beat than cancer, then taking the notion to a logical conclusion, one would assume sports people to live longer. International cricketer Shane Warne retired in 2007. In 2022, he died from a suspected heart attack at fifty-two.
That said, much of Sinclair’s research is interesting, if not complicated, stuff. The hallmarks of aging are the accumulation of senescent cells. Basically, cellular senescence is when cells stop dividing. On top of that, these cells release inflammatory molecules. Even though these cells are thought of as “zombie” cells, act much like the walking dead; still alive and wreaking mayhem on their neighbours.
It is thought zombie cells are created by telomeres. At the end of our chromosomes are these distinctive little structures that comprise the same sequence and are repeated over and over about 3,000 times and reach up to 15,000 base pairs in length. When a telomere becomes short, it is like a hole in a bag of popcorn. Just as the hole exposes popcorn, chromosomes become exposed and many bad things happen.
These zombie cells release tiny proteins called cytokines. Cytokines cause inflammation. Our bodies fight back with specialised cells that detect and destroy bacteria and other harmful organisms. These macrophages also release antigens to T cells. The zombie apocalypse begins, resulting in unhealthy inflammation. Excess cytokine proteins are the driving force behind heart disease, diabetes, and dementia, as well as multiple sclerosis and psoriasis.
As dire as senescent cells appear, medical research is experimenting with drugs called senolytics to kill them off, and everyone lives happily ever after.
The news also gets better for Australians who are not just living longer, but better than their forebears.
“In 2018, Australia ranked seventh on the global Human Capital index, just behind Singapore, Korea, Japan, Hong Kong, Finland, and Ireland.”
In stark contrast, the news is not so good for Sinclair’s home country, The United States of America.
“Thanks to the burgeoning addiction to calories and opioids, and a health care system that is inadequate, if not completely inaccessible to one-third of its population, the United States recently experienced a decline in life expectancy for the first time since the early 1960s.”
Sinclair doesn’t recommend supplements. He takes 1,000mg of NMN each morning to raise nicotinamide adenine nucleotides or NAD. NAD is a chemical used for over five-hundred chemical reactions. It is also vital for sirtuins, an enzyme that controls longevity and is found in organisms from yeast to humans. Some people take nicotinamide riboside, NR, because it is cheaper. Others take Niacin-vitamin B3, and nicotinamide—a form of vitamin B3 found in food and supplements mostly used to treat pellagra (niacin deficiency), however, these do not raise the NAD levels as much.
Sinclair also takes resveratrol and metformin (a drug used to treat type 2 diabetes), along with vitamin D, K, and a small dose of aspirin.
The good news is you don’t always have to take drugs to increase NAD levels. Sinclair believes eating fewer meals helps to promote longevity. The benefits of short-term fasting have been around for some time. Celebrity doctors such as Michael Mosley believe fewer calories improve blood pressure, help the brain, and benefit blood sugar control.
Not only does putting your body under stress by dieting, but exercise also increases NAD levels.
Sinclair also avoids smoking, excessive exposure to UV, and eats a mostly plant-based diet. He also partakes in thermal shocks, such as diving into ice-cold water after a sauna. Sleep doctors, or somnologists, have long warned about overheating bodies in bed. Sinclair tries to “stay on the cool side both during the day and at night.”
Lifespan—Why We Age—and Why We Don’t Have To: David A. Sinclair PhD. with Matthew D. La Plante was published in 2019; an unfortunate release date, as it was right before COVID and Putin’s war.
During 2022, Australian deaths were 17% above the historical rate. Older people died from a contagious virus. It temporarily, one hopes, lowered the country’s life expectancy. The global pandemic was a ‘black swan’ event Sinclair referred to when Bill Gates warned of a global outbreak in 2014. If only Sinclair could have foreseen the impending global malaise. But then, no one knows the future, especially when it comes to dying.
David Sinclair’s next book will have an interesting twist, I should imagine, given the intervening events.
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