Cutting calories and eating at the right time of day leads to longer life in mice

One of the recipes for extending your life is easy, if not easy. Is to eat less. Studies in a variety of animals have shown that limiting calories can lead to a longer and healthier life.

Now, new research suggests that the daily rhythm of the body plays a major role in this longevity effect. Howard Hughes Medical Institute researchers Joseph Futa Kahashi and colleagues reported in a journal dated May 5, 2022 that eating only during the most active hours significantly extended the lifespan of mice with a low-calorie diet. doing. Chemistry..

In a four-year study of hundreds of mice by his team, a low-calorie diet alone extended animal lifespan by 10%. However, mice are fed only at night, when they are most active and extend their lifespan by 35%. The combo (low-calorie diet and evening diet schedule) added an additional 9 months to the median typical 2-year lifespan of an animal. For people, similar plans will limit meals to daytime hours.

Takahashi, a molecular biologist at the University of Texas Southwestern Medical Center, helps to dispel the controversy over diet plans that emphasize eating only at specific times.Like recent studies, such plans may not accelerate human weight loss New England Journal of Medicine Although reported, they may promote health benefits that lead to longer lifespans.

The findings of Takahashi’s team highlight the important role of metabolism in aging, said Sai Krupa Das, a nutrition scientist at the Jean Mayer USDA Center for Human Nutrition Research on Aging, who was not involved in the study. “This is a very promising and groundbreaking study,” she says.

Fountain of youth

Decades of research have shown that calorie restriction extends the lifespan of animals, from worms and flies to mice, rats and primates. These experiments report weight loss, improved glucose regulation, lowering blood pressure, and reduced inflammation.

However, Das says it was difficult to systematically study calorie restriction in people who could not live in the lab and could not eat the measured food portion throughout their lives. She was part of a research team that conducted a comprehensive assessment of the long-term effects of reduced energy intake, or the first controlled study of human calorie restriction called CALERIE. In that study, even a slight reduction in calories was “extremely beneficial” in reducing the signs of aging, says Das.

Scientists are just beginning to understand how calorie restriction slows aging at the cellular and genetic levels. As animals grow older, genes associated with inflammation tend to be more active, while genes that help regulate metabolism become less active. Takahashi’s new study found that calorie restriction helps offset these genetic changes as mice age, especially when adapted to the duration of mouse activity at night.

Just a matter of time

In recent years, many popular diet programs have emerged that focus on what is known as an intermittent fasting. For example, fasting every other day or fasting for 6-8 hours a day. To elucidate the effects of calories, fasting, daily rhythms, or circadian rhythms on longevity, Takahashi’s team conducted a large four-year experiment. The team housed hundreds of mice with automatic feeders and controlled when and how much each mouse ate throughout its lifespan.

Some mice were able to eat as much as they wanted, while others were 30-40 percent limited in calories. And those on a calorie-restricted diet ate on different schedules. The team found that mice fed a low-calorie diet at night lived the longest, either for 2 or 12 hours.

The results suggest that a time-limited diet has a positive effect on the body without promoting weight loss. New England Journal of Medicine Studies have suggested. Takahashi points out that his study also showed no difference in body weight between mice with different feeding schedules. “But there was a big difference in lifespan,” he says.

Rafael de Cabo, a gerontologist at the National Institute on Aging in Baltimore, said: Chemistry Paper is a very elegant demonstration of limiting calories but not. [eating at the right times], You cannot fully enjoy the benefits of calorie restriction. “

Takahashi hopes that learning how calorie restriction affects the body clock with aging will help scientists find new ways to extend the healthy lifespan of humans. It can come through calorie-restricted diets or through medications that mimic the effects of those diets.

Meanwhile, Takahashi is taking lessons from mice. He limits his diet to 12 hours. But he says, “Once you find a medicine that can raise your watch, you can test it in the lab to see if it extends your lifespan.”