Healthy Diet of Fruit and Vegetables Extends Life Expectancy in Women

Women in their seventies who exercise and eat healthy amounts of fruits and vegetables have a longer life expectancy, according to research published in the Journal of the American Geriatrics Society.

Researchers at the University of Michigan and Johns Hopkins University studied 713 women aged 70 to 79 years who took part in the Women's Health and Aging Studies. This study was designed to evaluate the causes and course of physical disability in older women living in the community.

"A number of studies have measured the positive impact of exercise and healthy eating on life expectancy, but what makes this study unique is that we looked at these two factors together," explains lead author, Dr. Emily J Nicklett, from the University of Michigan School of Social Work.

Researchers found that the women who were most physically active and had the highest fruit and vegetable consumption were eight times more likely to survive the five-year follow-up period than the women with the lowest rates.

To estimate the amount of fruits and vegetables the women ate, the researchers measured blood levels of carotenoids-beneficial plant pigments that the body turns into antioxidants, such as beta-carotene. The more fruits and vegetables consumed, the higher the levels of carotenoids in the bloodstream..

Study participants' physical activity was measured through a questionnaire that asked the amount of time the spent doing various levels of physical activity, which was then converted to the number of calories expended.

The women were then followed up to establish the links between healthy eating, exercise and survival rates.

Key research findings included:

• More than half of the 713 participants (53%) didn't do any exercise, 21% were moderately active, and the remaining 26% were in the most active group at the study's outset.
• During the five-year follow up, 11.5% of the participants died. Serum carotenoid levels were 12% higher in the women who survived and total physical activity was more than twice as high.
• Women in the most active group at baseline had a 71% lower five-year death rate than the women in the least active group.
• Women in the highest carotenoid group at baseline had a 46% lower five-year death rate than the women in the lowest carotenoid group.
• When taken together, physical activity levels and total serum carotenoids predicted better survival.

"Given the success in smoking cessation, it is likely that maintenance of a healthy diet and high levels of physical activity will become the strongest predictors of health and longevity. Programs and policies to promote longevity should include interventions to improve nutrition and physical activity in older adults," said Dr. Nicklett.

When You Eat Matters, Not Just What You Eat

When it comes to weight gain, when you eat might be at least as important as what you eat.

When mice on a high-fat diet are restricted to eating for eight hours per day, they eat just as much as those who can eat around the clock, yet they are protected against obesity and other metabolic ills, the new study shows. The discovery suggests that the health consequences of a poor diet might result in part from a mismatch between our body clocks and our eating schedules.

"Every organ has a clock," said lead author of the study Satchidananda Panda of the Salk Institute for Biological Studies. That means there are times that our livers, intestines, muscles, and other organs will work at peak efficiency and other times when they are—more or less—sleeping.

Those metabolic cycles are critical for processes from cholesterol breakdown to glucose production, and they should be primed to turn on when we eat and back off when we don't, or vice versa. When mice or people eat frequently throughout the day and night, it can throw off those normal metabolic cycles.

"When we eat randomly, those genes aren't on completely or off completely," Panda said. The principle is just like it is with sleep and waking, he explained. If we don't sleep well at night, we aren't completely awake during the day, and we work less efficiently as a consequence.

To find out whether restricted feeding alone—without a change in calorie intake—could prevent metabolic disease, Panda's team fed mice either a standard or high-fat diet with one of two types of food access: ad lib feeding or restricted access.

The time-restricted mice on a high-fat diet were protected from the adverse effects of a high-fat diet and showed improvements in their metabolic and physiological rhythms. They gained less weight and suffered less liver damage. The mice also had lower levels of inflammation, among other benefits.

Panda says there is reason to think our eating patterns have changed in recent years, as many people have greater access to food and reasons to stay up into the night, even if just to watch TV. And when people are awake, they tend to snack.

The findings suggest that restricted meal times might be an underappreciated lifestyle change to help people keep off the pounds. At the very least, the new evidence suggests that this is a factor in the obesity epidemic that should be given more careful consideration.

"The focus has been on what people eat," Panda said. "We don't collect data on when people eat."