A small pilot study shows for the first time that changes in diet, exercise, stress management and social support may result in longer telomeres（染色体终端）, the parts of chromosomes that affect aging. It is the first controlled trial to show that any intervention might lengthen telomeres over time.

The study was conducted by scientists at UC San Francisco and the Preventive Medicine Research Institute, a nonprofit public research institute in Sausalito, Calif. that investigates the effect of diet and lifestyle choices on health and disease. The researchers say they hope the results will inspire larger trials to test the validity of the findings.

"Our genes, and our telomeres, are not necessarily our fate," said lead author Dean Ornish, MD, UCSF clinical professor of medicine, and founder and president of the Preventive Medicine Research Institute.

"So often people think 'Oh, I have bad genes, there's nothing I can do about it,'" Ornish said. "But these findings indicate that telomeres may lengthen to the degree that people change how they live. Research indicates that longer telomeres are associated with fewer illnesses and longer life."

Telomeres are the protective caps on the ends of chromosomes that affect how quickly cells age. They are combinations of DNA and protein that protect the ends of chromosomes and help them remain stable. As they become shorter, and as their structural integrity weakens, the cells age and die quicker.

In recent years, shorter telomeres have become associated with a broad range of aging-related diseases, including many forms of cancer, stroke, vascular（血管的） dementia, cardiovascular disease, obesity, osteoporosis（骨质疏松症） and diabetes.

For five years, the researchers followed 35 men with localized, early-stage prostate cancer to explore the relationship between comprehensive lifestyle changes, and telomere length and telomerase activity. All the men were engaged in active surveillance, which involves closely monitoring a patient's condition through screening and biopsies.

Ten of the patients embarked on lifestyle changes that included: a plant-based diet (high in fruits, vegetables and unrefined grains, and low in fat and refined carbohydrates); moderate exercise (walking 30 minutes a day, six days a week); stress reduction (gentle yoga-based stretching, breathing, meditation). They also participated in weekly group support.

They were compared to the other 25 study participants who were not asked to make major lifestyle changes.

The group that made the lifestyle changes experienced a "significant" increase in telomere length of approximately 10 percent. Further, the more people changed their behavior by adhering to the recommended lifestyle program, the more dramatic their improvements in telomere length, the scientists learned.