Molecular biologist Elizabeth Blackburn shared a Nobel Prize for her research on telomeres — structures at the tips of chromosomes that play a key role in cellular aging. But she was frustrated that important health implications of her work weren't reaching beyond academia.
So along with psychologist Elissa Epel, she has published her findings in a new book aimed at a general audience — laying out a scientific case that may give readers motivation to keep their new year's resolutions to not smoke, eat well, sleep enough, exercise regularly, and cut down on stress.
The main message of "The Telomere Effect," being published Tuesday, is that you have more control over your own aging than you may imagine. You can actually lengthen your telomeres — and perhaps your life — by following sound health advice, the authors argue, based on a review of thousands of studies.
"Telomeres listen to you, they listen to your behaviors, they listen to your state of mind," said Blackburn, president of the Salk Institute for Biological Studies in La Jolla, Calif.
Telomeres sit at the end of strands of DNA, like the protective caps on shoelaces. Stress from a rough lifestyle will shorten those caps, making it more likely that cells will stop dividing and essentially die.
Too many of these senescent cells accelerates human aging, the pair say. This doesn't cause any particular disease, but research suggests that it hastens the time when whatever your genes have in store will occur — so if you're vulnerable to heart disease, you're more likely to get it younger if your telomeres are shorter, said Epel, director of the University of California, San Francisco's Aging, Metabolism and Emotions Center.
"We can provide a new level of specificity and tell people more precisely with clues emerging from telomere science, what exactly about exercise is related to long telomeres, what exact foods are related to long telomeres, what aspects of sleep are more related to long telomeres," Epel added.
Other researchers in the field praised Blackburn and Epel's efforts to make telomere research relevant to the general public, though several warned that it risked oversimplifying the science.
"I think it's a very difficult thing to prove conclusively" that lifestyle can affect telomere length and therefore lifespan, said Harvard geneticist and anti-aging researcher David Sinclair. "To get cause-effect in humans is impossible, so it's based on associations."
Judith Campisi, an expert on cellular aging at the Buck Institute for Research on Aging in Novato, Calif., said the underlying research is solid. "If you have a terrible diet and you smoke, you're definitely shortening your life, and shortening your telomeres," she said.
Shortening and lengthening telomeres
Short telomeres increase the likelihood of cells becoming senescent and producing molecules that lead to inflammation, which she said is a huge risk factor for every age-related disease. "So there is a link there," Campisi said, "it's just not this exclusive magic bullet, that's all."
Cells can age in different ways, so someone could have lots of aging cells but normal-looking telomeres. "If all aging was due to telomeres, we would have solved the aging problem a long time ago," she said.
In a telephone interview from her publisher's office in New York, Blackburn said the best part of the telomere research is that it's quantifiable, giving people more specific direction than the advice your mother may have given you to get off the couch and exercise.
"Your mother didn't tell you if you had to run marathons every week, or if three to four times a week is enough," she said. Telomere research suggests that extreme exercise isn't necessary to live healthier longer.
Also, Blackburn said, her research suggests that lengthening telomeres with medications could be dangerous — that lifestyle changes are far safer than a pill.
One surprise from the research: You don't actually need a full eight hours of sleep to benefit your telomeres. Seven is enough, as long as you feel well-rested. "That's something quite useful, so people won't lie awake fretting that they're not getting eight hours," Blackburn said.
One of the challenges with telomere research is that most studies measure the length of telomeres in blood cells. But it may be that the liver is aging faster or slower than the blood — we're not all one age throughout, Campisi said.
By measuring telomere length in the blood, "what you're really reporting on is the capacity of immune stem cells to function well," said Matt Kaeberlein, who studies the molecular basis of aging at the University of Washington. "What this may be really telling us is the immune system may be particularly sensitive to lifestyle and environmental factors."
But how much of an effect can there be?
Kaeberlein said he's only at the periphery of telomere research, but is skeptical about the predictive value of shorter versus longer telomeres.
"It's not at all clear whether the methods are quantitative enough or of high enough resolution to really make those kinds of arguments," Kaeberlein said. "I think it has the potential to be a biomarker predicting health outcomes, but I don't know that I would feel comfortable saying people should make lifestyle changes based on a measure of their telomere length," he said.
Sara Gottfried did. A Harvard-trained gynecologist in Berkeley, Calif., she said a test of her telomere length put her 20 years beyond her biological age, and shocked her into action.
"It was an interesting anecdotal experiment," said Gottfried, whose examination led to a book, due out in March, called "Younger: A Breakthrough Program to Reset Your Genes, Reverse Aging, and Turn Back the Clock 10 Years." "It organized my thinking around the levers of health span — food, sleep, exercise, lean body mass, stress — how so many of us are in a failure state, which I think accelerates aging."