Cox News Service
ATLANTA -- Everyone wants a long, healthy life. We all know that
genetic makeup is one key to longevity, but what if you are looking
for another way to live longer?
Enter caloric restriction, an idea that has been around since
the 1930s when scientists discovered that feeding mice about half
their caloric needs lived longer than the mice given standard lab
chow. Studies have shown that other animals, including apes, can
extend life by eating less. How does that apply to humans?
Perusing the Caloric Restriction Society Web site
(www.calorierestriction.org), it is clear that some people are
performing their own experiments by voluntarily restricting
calories by 30 percent to 40 percent of what is recommended by the
Dietary Reference Intakes for healthy adults.
Maximum human life span is thought to be 120 years, and the
proponents of caloric restriction hope to break through the life
span ceiling. To get the proper amount of nutrients, a CR diet has
to ensure that malnutrition isn't a side effect. Indeed,
malnutrition can shorten your life span by weakening your immune
system. Some people who follow CR diets call themselves
"CRONies," for Caloric Restriction With Optimal Nutrition. The
diet is mostly fruits and vegetables with a few whole grains and
very little meat.
CR also reduces the production of free radicals - those pesky
side effects of metabolism that some think trigger aging. CR also
helps lower the amount of insulin that your body produces, which
could prevent diabetes, and is linked to maintaining healthy brain
cells that could retard neurological diseases such as dementia and
Parkinson's disease.
Unanswered questions about CR include how severe does the
caloric restriction need to be to see the benefits shown in
animals? How long do you have to follow the diet to increase
longevity? Are the effects seen only during the calorie restriction
phase or are there long-lasting benefits? One researcher, writing
in the Journal of Gerontology, developed a mathematical model and
predicted that CR would only extend life by one to five years.
The best strategy is to achieve and maintain a healthy body
weight, be active every day and eat more fruits and vegetables,
especially those with deep, rich colors. And, if you are tempted to
try CR, remember that the oldest known human didn't live a CR
lifestyle.
Chris Rosenbloom, Ph.D., R.D., is a professor of nutrition in
the College of Health and Human Sciences at Georgia State
University. She'll answer nutrition questions of general interest.
Send your questions to her c/o The Atlanta Journal-Constitution,
Sixth Floor, 72 Marietta St. N.W., Atlanta, GA 30303. Or e-mail her
at dietitian AT ajc.com.