Caloric Restriction: Friend or Foe?
Caloric restriction is an experimental tool that utilizes "undernutrition without malnutrition." In other words, caloric restriction refers to a diet with between 30-40 percent fewer calories than is typical, but which contains all the necessary nutrients and vitamins to support life.
Caloric restriction seems to slow down some of the destructive processes that take place in cells and tissues with aging. Scientists don't yet know exactly how or why it works, but have developed several theories.
First of all, caloric restriction seems to reduce damage from chemical metabolic processes, particularly oxidative and glycation damage, thought to be leading causes of cell aging and death.
On a larger scale, caloric restriction slows the effects of aging on the nervous system, the reproductive organs and the production of hormones in some animals. It has been shown to boost the immune system and delay the onset of certain age-related cancers.
In experimental testing, caloric restriction showed promise only in experimental animals. Caloric restriction has been shown to increase both the average and the maximal life spans in paramecia, worms, spiders, insects, and rodents. Preliminary results suggested that calorie-restricted monkeys are healthier and tend to live longer than their freely fed counterparts.
Even if caloric restriction does not work in humans, studying its mechanisms is still very important. Caloric restriction seems to prevent or delay many age-associated diseases and conditions, such as heart disease, dementia, and cancer. If scientists can figure out how it works, they might be able to develop drugs that mimic its effects without requiring people to drastically reduce their calorie intake and risk potentially dangerous side effects. The main goal of mimicking caloric restriction through drugs is not necessarily to increase lifespan, but to reduce the incidence or delay the onset of age-related diseases and conditions and thereby improve the quality of later life.
The Other Side: Starving Won't Make People Live Longer
Researchers at various universities and the national Institutes of Health are testing the theories but there are groups already cutting calories by up to a third in the hope they can live to be 120 or 125, while staying healthy.
"Our message is that suffering years of misery to remain super-skinny is not going to have a big payoff in terms of a longer life," said Phelan, an evolutionary biologist, in a statement.
The idea of caloric restriction has been gaining credence as scientists test it in more and more animals. It is easy to show that creatures that have short life spans such as mice, fish and spiders live longer if they eat less.
Most Recent Studies Still Support Caloric Restriction
New studies in Germany enforce the fact that restricting calories does have benefits for animals, but a new study is indicating that humans can improve their memory when they cut back on food.
Researchers from Germany advised some people to cut their calorie consumption by 30 percent, while others increased unsaturated fat intake without cutting calories and a third group made no dietary changes (study participants ranged in age from 50 to 72). Over the course of three months, those who restricted their calories saw a 20 percent improvement in memory, on average, while the other groups had no significant change. Researchers think the difference may be lower levels of insulin in the blood of people who consume fewer calories, which may improve brain function.
You may also find of interest...
- Calories Shown to Improve Memory in the Elderly
- Growing Older, Eating Better
- The Elderly and Eating Well
- Nutritional Needs As We Age
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