Robert Bazell is adjunct professor of molecular, cellular and developmental biology at Yale. For 38 years he was chief science correspondent for NBC News.

Stay Young Forever (or Die Trying)

By Bill Gifford

Grand Central. 366 pp. $27

Tom Perls, an amiable, boyish-looking professor at Boston University, has earned a respectable place in the hierarchy of academic medicine. But measured by media attention, Perls is a contender for the top echelons. He’s given hundreds of interviews to newspapers, magazines and television — I conducted a dozen myself. Perls studies aging, a subject few editors can resist. Since 1995, he’s located hundreds of people who stayed healthy beyond their 100th birthday

Perls searched for common behaviors in the healthy centenarians. Some smoked and drank, others didn’t. Some had been fat, some skinny. No pattern emerged. At one point he suggested dental flossing as a common denominator. He turned to genetics and in a 2011 paper identified slight changes in 130 genes that may help people live longer and healthier. That’s far too much complexity for any individual or drug company seeking a ticket to the fountain of youth.

‘Spring Chicken: Stay Young Forever (or Die Trying)’ by Bill Gifford (Grand Central)

Perls appears briefly in Bill Gifford’s “Spring Chicken.” So do other scientists well-regarded by their peers, along with a parade of hucksters. Gifford starts with Charles Edouard Brown-Séquard, who at age 72 in 1889 told the Société de Biologie in Paris that he had regained much of his vigorous youth with injections of the mashed testicles of young dogs and guinea pigs. Almost overnight, entrepreneurs were selling “Séquard’s Elixir of Life.” The fad died along with Brown-Séquard five years later.

Gifford, a journalist in his late 40s, wrote the book “to hang on to his youth, or what was left of it, for as long as possible.” Spoiler alert: He didn’t find the elixir. Still, his survey of those who study aging and those who claim they can slow it down or stop it makes for a great read, even if other books, notably Stephen Hall’s “Merchants of Immortality” (2003), have covered much of the same material more thoroughly.

Aging research has two goals. The first, living longer, is already happening around the world because of improved nutrition, a drop in infectious disease and better treatments for heart ailments. The second, achieving longevity without the disability that so many older folks suffer or fear, remains elusive. Most of those profiled by Gifford work toward the second goal, but some toward both.

Roy Walford, a professor at UCLA, latched on to a 1935 laboratory observation that rats fed a near-starvation diet with adequate nutrition lived longer. He published a book, “The 120 Year Diet,” and attracted adherents who formed the Calorie Restriction Society. Responding to the enthusiasm, the National Institute on Aging spent $40 million to starve two groups of monkeys for decades, comparing them with normally fed animals. One group of hungry monkeys lived slightly longer. The other didn’t. Walford volunteered to enter the bizarre human terrarium called Biosphere, a decision that may have severely damaged his health. He died a wreck at age 79.

Actress Suzanne Somers, 68, sets her goal at 110. She told Oprah Winfrey that she takes 40 supplements every morning, followed by a bolus of estrogen directly into her vagina, then another 20 pills at night. “I’m loving my life. I have a sex drive,” Gifford quotes her as saying at an anti-aging conference. “My friends, none of ’em are having sex.”

Many of the aged must want to escape the second fate. Gifford shines light on the growing sales of human growth hormone and testosterone supplements by shady outfits and big drug companies, despite ample evidence that both could be detrimental. He discovers that the genes we inherit remain the major determinant of how healthy we are in old age. We can shift the odds some by avoiding tobacco, exercising, controlling cholesterol and maintaining a normal body weight. I suspect you have heard that.

Gifford points out that Darwinian evolution leads to the conclusion that death must be programmed into us to make room for the next generation. He says that “this notion has been enormously popular with students and everyone else under the age of twenty-five.” Actually the inevitability of death is a fundamental tenet of biology. People of all ages could do well to accept it.