Exercise boosts benefits of calorie restriction on longevity

Exercise boosts the benefits of calorie restriction which is turn kickstarts the human metabolism to extend lifespan.

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Scientists at the Buck Institute for Research on Aging report in the magazine Cell Metabolism the outcome of experiments, that suggest that it may be necessary to be physically active in order to derive maximum benefit from dietary restriction (DR). 
Significant restriction of the intake of a particular nutrient or total calories has extended the life span of numerous species in laboratory experiments; however, researchers are still clarifying the mechanisms involved in the techniqueIn research involving fruit flies, Pankaj Kapahi, PhD and colleagues observed that the insects became more physically active when their protein source was restricted. The increased physical activity observed in the dietary-restricted flies was associated with greater fat synthesis and breakdown. 
When fat synthesis in muscle tissue was blocked, so was the life-extending benefit of dietary restriction. And in flies whose motion was limited, the extended life span that normally results from a restricted diet did not occur. 
“Ours is the first study to suggest that for dietary restriction to enhance lifespan, you need increased fat turnover in the muscle and an associated increase in physical activity,” Dr Kapahi announced. “Furthermore, it also suggests that dietary changes may enhance motivation to exercise and help derive maximal benefits of exercise.”In flies genetically engineered to overexpress the hormone AKH, metabolism and activity levels were enhanced and lifespan was extended, even without dietary restriction.
 “Our data suggests that DR may induce changes in muscle similar to those observed under endurance exercise and that molecules like AKH could serve as potential mimetics for DR that enhance activity and healthspan,” remarked lead author and Buck Institute staff scientist Subhash D. Katewa, PhD. 
“A better understanding of the dynamics of fat metabolism is needed in order to clarify its role in aging and disease. These current results suggest that enhanced fat metabolism could help slow aging and the onset of age-related disease.
“Dietary restriction is known to enhance spontaneous movement in a variety of species including primates, however this is the first examination of whether enhanced physical activity is necessary for its beneficial effects,” Dr Kapahi added.
 “This study establishes a link between DR-mediated metabolic activity in muscle, increased movement and the benefits derived from restricting nutrients. Our work argues that simply restricting nutrients without physical activity may not be beneficial in humans.”
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Does calorie restriction boost brain power?


Berlin: Cutting calories may boost memory as well as increasing lifespan, according to a new study from Germany.

Older adults who cut down on the amount of calories they consume get a two-for-one special: weight loss and better memory, say scientists from the University of Munster, in a study published in the journal Proceedings of the National Academy of Sciences.

They found that healthy women ranging in age from 50 to 80 who reduced their calorie intake by 30 percent for three months not only lost weight, but their scores on verbal memory tests also increased by 20 percent,

The study included 50 women, all of whom were either normal weight or slightly overweight. (The average body mass index was 28, which is about 175 pounds for a woman who is 5’6″.)

Twenty went on a calorie-cutting diet, another 20 upped their intake of unsaturated fatty acids (which some studies suggest may help ageing brains), and the remaining 10 kept to a normal diet.

Unlike the women who cut down on calories, the women who ate more unsaturated fatty acids showed no improvement in their memories, nor did those in the control group.

The researchers showed that women who cut calories became more sensitive to the blood sugar– regulating hormone insulin and had a drop in the inflammation-associated molecule C-reactive protein. Both factors have been linked to an improvement in brain function.

The findings add to growing evidence that calorie restriction can benefit health and longevity, but this shouldn’t prompt already skinny seniors to start dieting. Older people who lose too much weight increase their risk of falls and fractures.

And eating less isn’t the only way to get this effect. Exercise appears to exert similar effects on brain function by boosting insulin sensitivity and fighting inflammation.

Participants in the study who reduced their calorie intake met several times with dietitians for advice and were instructed not to eat less than 1,200 calories.

Experts believe that, increased inflammation and a drop in insulin sensitivity (which is known as insulin resistance) may help explain why obesity and type 2 diabetes have been linked to worse mental performance and a greater risk of Alzheimer’s disease.

Meanwhile, studies in animals dating back to the 1980s show caloric restriction can extend lifespan and slow aging. The current findings is another piece of evidence that what we see in laboratory rodents on caloric restriction translates to humans

Most studies in humans have looked at people who choose to sharply reduce their calorie intake long-term, he noted. This research has found clear signs of reduced cardiovascular disease risk, and perhaps slower ageing, in these individuals. But this kind of lifestyle change isn’t easy and is best done with professional help, Weindruch said. Health.com: 6 diet trends you should never try

Researchers who study caloric restriction have two main theories on how it might slow aging. One argument is that eating less slows down metabolism, so that the body produces fewer free radicals, which are byproducts of oxygen metabolism that can harm body tissues.

Another is that reducing calorie intake keeps cells under a constant low level of stress, which makes them better able to cope with higher levels of stress when it comes along similar to how the moderate stress induced by exercise can improve people’s health.

The German study will continue with larger studies of calorie restriction and mental function and will perform MRI brain scans on participants before and after they reduce their food intake in order to better understand what’s happening in the brain’s gray matter.

In the meantime, the findings offer yet another reason for people to try eating a little less.