Why we die The new science of aging and the quest for immortality

This discerning study by Ramakrishnan (Gene Machine), a Nobel Prize--winning molecular biologist, examines the science of aging and efforts to stop it. Discussing the molecular processes that contribute to aging, he explains that the ends of chromosomes feature repeated genetic sequences, some of which are lost every time a cell divides until the replicated sequences have been exhausted. At that point, the cell stops dividing, reducing the body's capacity to regenerate tissue. Ramakrishnan demonstrates a healthy skepticism when surveying attempts to extend human life, suggesting that while some animal studies indicate calorie-restricted diets and transfusing younger individuals' blood into older patients might slow aging, there's not yet enough evidence that these strategies would work for humans. The author has a knack for making biology accessible ("You can think of damage to mitochondria from oxidation as a case of our cells rusting from within"), and he brings a searching philosophical sensibility when considering the wisdom of seeking to extend life, cautioning that "a greatly extended life span would deprive our lives of urgency and meaning, a desire to make each day count." The result is a strikingly pensive exploration of how bodies decline and whether efforts to slow that process are worth the cost. (Mar.)

A Nobel Prize winner in chemistry examines aging and dying. Ramakrishnan, a molecular biologist and the author of The Gene Machine, writes that biologists don't consider aging "inevitable." Progress has diminished human wear and tear over the past century and doubled our longevity without increasing our maximal lifespan. No one has matched Jeanne Calment, who died 25 years ago at 122, though she was feeble, blind, and deaf during her final years. Ramakrishnan emphasizes that all living things can die, but many, including tiny hydras and some jellyfish, can regenerate completely when certain parts are chopped off. Their likelihood of dying does not increase with age, so they are considered biologically immortal. More familiar animals--giant tortoises, some sharks--age extremely slowly, and we have plenty to learn from these creatures. Ramakrishnan is a fine writer, so readers will enjoy his expert if intensely detailed overview of genetics and evolution as it applies to aging. Those who pay attention will be rewarded by his modestly optimistic conclusion about life extenders, which are familiar to health-conscious readers and heavily promoted by entrepreneurial colleagues. The author includes fascinating studies demonstrating that the front-runners--rapamycin, resveratrol, metformin, curcumin--and calorie restriction extend the lives of animals, including primates. However, having no skin in the game, the author breaks ranks with enthusiasts by recounting failed studies. He holds a low opinion of respectable colleagues who promote the elderly male billionaires who finance their startups, as well as the bizarre but flourishing cryonics industry, which freezes people immediately after death "with the idea of defrosting them when a cure for whatever ailed them has been found." In the end, Ramakrishnan believes that vast lifespans will happen, but not in the near future. An illuminating account of the science of life extension with a more critical eye than most. Copyright (c) Kirkus Reviews, used with permission.