MSGID: 1:317/3 6274a4ee   
   PID: hpt/lnx 1.9.0-cur 2019-01-08   
   TID: hpt/lnx 1.9.0-cur 2019-01-08   
    Cutting calories and eating at the right time of day leads to longer   
   life in mice    
      
     Date:   
         May 5, 2022   
     Source:   
         Howard Hughes Medical Institute   
     Summary:   
         In a study that followed hundreds of mice over their lifespans,   
         calorie restriction combined with time-restricted eating boosted   
         longevity.   
      
      
      
   FULL STORY   
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   One recipe for longevity is simple, if not easy to follow: eat   
   less. Studies in a variety of animals have shown that restricting calories   
   can lead to a longer, healthier life.   
      
      
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   Now, new research suggests that the body's daily rhythms play a big part   
   in this longevity effect. Eating only during their most active time of   
   day substantially extended the lifespan of mice on a reduced-calorie   
   diet, Howard Hughes Medical Institute Investigator Joseph Takahashi and   
   colleagues report May 5, 2022, in the journal Science.   
      
   In his team's study of hundreds of mice over four years, a reduced-calorie   
   diet alone extended the animals' lives by 10 percent. But feeding mice   
   the diet only at nighttime, when mice are most active, extended life   
   by 35 percent. That combo -- a reduced-calorie diet plus a nighttime   
   eating schedule -- tacked on an extra nine months to the animals' typical   
   two-year median lifespan. For people, an analogous plan would restrict   
   eating to daytime hours.   
      
   The research helps disentangle the controversy around diet plans   
   that emphasize eating only at certain times of day, says Takahashi,   
   a molecular biologist at the University of Texas Southwestern Medical   
   Center. Such plans may not speed weight loss in humans, as a recent   
   study in the New England Journal of Medicine reported, but they could   
   prompt health benefits that add up to a longer lifespan.   
      
   Takahashi's team's findings highlight the crucial role of metabolism in   
   aging, says Sai Krupa Das, a nutrition scientist at the Jean Mayer USDA   
   Human Nutrition Research Center on Aging who was not involved with the   
   work. "This is a very promising and landmark study," she says.   
      
   Fountain of youth Decades of research has found that calorie restriction   
   extends the lifespan of animals ranging from worms and flies to mice,   
   rats, and primates. Those experiments report weight loss, improved   
   glucose regulation, lower blood pressure, and reduced inflammation.   
      
      
      
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   Butit has been difficult to systematically study calorie restriction in   
   people, who can't live in a laboratory and eat measured food portions   
   for their entire lives, Das says. She was part of the research team that   
   conducted the first controlled study of calorie restriction in humans,   
   called the Comprehensive Assessment of Long-term Effects of Reducing   
   Intake of Energy, or CALERIE. In that study, even a modest reduction   
   in calories "was remarkably beneficial" for reducing signs of aging,   
   Das says.   
      
   Scientists are just beginning to understand how calorie restriction slows   
   aging at the cellular and genetic level. As an animal ages, genes linked   
   to inflammation tend to become more active, while genes that help regulate   
   metabolism become less active. Takahashi's new study found that calorie   
   restriction, especially when timed to the mice's active period at night,   
   helped offset these genetic changes as mice aged.   
      
   Question of time Recent years have seen the rise of many popular diet   
   plans that focus on what's known as intermittent fasting, such as fasting   
   on alternate days or eating only during a period of six to eight hours per   
   day. To unravel the effects of calories, fasting, and daily, or circadian,   
   rhythms on longevity, Takahashi's team undertook an extensive four-year   
   experiment. The team housed hundreds of mice with automated feeders to   
   control when and how much each mouse ate for its entire lifespan.   
      
   Some of the mice could eat as much as they wanted, while others had their   
   calories restricted by 30 to 40 percent. And those on calorie-restricted   
   diets ate on different schedules. Mice fed the low-calorie diet at   
   night, over either a two-hour or 12-hour period, lived the longest,   
   the team discovered.   
      
      
      
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   The results suggest that time-restricted eating has positive effects   
   on the body, even if it doesn't promote weight loss, as the New England   
   Journal of Medicine study suggested. Takahashi points out that his study   
   likewise found no differences in body weight among mice on different   
   eating schedules - - "however, we found profound differences in lifespan,"   
   he says.   
      
   Rafael de Cabo, a gerontology researcher at the National Institute   
   on Aging in Baltimore says that the Science paper "is a very elegant   
   demonstration that even if you are restricting your calories but you   
   are not [eating at the right times], you do not get the full benefits   
   of caloric restriction."  Takahashi hopes that learning how calorie   
   restriction affects the body's internal clocks as we age will help   
   scientists find new ways to extend the healthy lifespan of humans. That   
   could come through calorie-restricted diets, or through drugs that mimic   
   those diets' effects.   
      
   In the meantime, Takahashi is taking a lesson from his mice - he restricts   
   his own eating to a 12-hour period. But, he says, "if we find a drug   
   that can boost your clock, we can then test that in the laboratory and   
   see if that extends lifespan."   
      
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   Story Source: Materials provided by Howard_Hughes_Medical_Institute. Note:   
   Content may be edited for style and length.   
      
      
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   Journal Reference:   
      1. Victoria Acosta-Rodri'guez, Filipa Rijo-Ferreira, Mariko Izumo,   
      Pin Xu,   
         Mary Wight-Carter, Carla B. Green, Joseph S. Takahashi. Circadian   
         alignment of early onset caloric restriction promotes longevity   
         in male C57BL/6J mice. Science, 2022; DOI: 10.1126/science.abk0297   
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   Link to news story:   
   https://www.sciencedaily.com/releases/2022/05/220505143753.htm   
      
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