The average life expectancy in the United States has fallen behind that of other industrialized nations as the American income gap has widened. In addition, better health habits, including those involving weight control, nutrition, and exercise, clearly influence the effects of aging among segments of the U.S. population.
“Widening inequalities in the U.S. are growing over time, not decreasing,” said Lisa Berkman, the Thomas D. Cabot Professor of Public Policy and of Epidemiology at the Harvard School of Public Health (HSPH) and director of the Harvard Center for Population and Development Studies.
Addressing an HSPH forum Tuesday called “Living Longer and Happier Lives: The Science Behind Healthy Aging,” she said mortality rates have increased among less-educated American women, and even wealthy Americans have a shorter life expectancy than their European counterparts.
“Diet does seem to make a difference,” said Francine Grodstein, professor of epidemiology at HSPH and professor of medicine at Harvard Medical School. The Nurses’ Health Study, a large longitudinal study that dates back to the 1970s, is a foundation for many of these conclusions.
“The higher our body weight and body mass index, the less likely we are to live older, happier, healthier lives,” she said.
William Mair, HSPH assistant professor of genetics and complex diseases, said a study that has gained a lot of attention found that reducing body weight by 20 percent in mice increased their longevity.
“If you take almost any organism, a fruit fly or a mouse, and reduce food intake by 20 percent, you get pronounced longer life,” he said. The frontier lies in understanding this process on a molecular level to apply the findings to human nutrition, he said.