"calorie restriction, CRON, calorie restriction with optimal nutrition."

Today I would like to share with you some interesting new findings that were announced recently by scientists at the University of California concerning calorie restriction.

Scientists have known for more than sixty years that by reducing the calorie intake of laboratory animals to about 60% of normal, while still maintaining adequate nutrition, they can actually slow the aging process and dramatically increase life expectancy. And the nice thing is that this process increases life expectancy not by extending old age, but by extending youthfulness.

Most of the research on this subject has been done with rodents and rhesus monkeys, and some with chimpanzees, because it would be almost impossible to conduct randomized controlled trials of human beings covering their entire life spans.

But very good studies have been done with human beings showing convincingly that the same general benefits from calorie restriction can be obtained by humans. (See references at the end of this article.)

In the February 28, 2003, issue of Science, several experts discussed the various techniques that have been attempted to slow the aging process, and every one of them ended by concluding that calorie restriction is the only method that works.

The maximum life span of rats has been extended more than 60% through calorie restriction, and the maximum life span of fish more than 300%.

Up until now the longest any human being has ever lived is somewhere around 113 years. That is what is meant by maximum life span. It is easy to increase maximum life span 50% in animals through calorie restriction. That would correspond to a maximum life span of between 150 and 160 years in humans.

It is unlikely that the maximum life in humans would ever be increased that much through calorie restrictions alone because most people would not want to subject themselves to that degree of restriction.

But many gerontologists, the scientists who study these things, believe the human life span might be extended to between 120 and 140 years through calorie restriction alone -- and not by extending old age, but by extending youthfulness at all ages. That has been the way it has consistantly worked with laboratory animals over the past 60 years.

Aside from the weight loss that results from calorie restriction I think the most interesting benefit is not the impressive increase in life span but the dramatic increases in learning ability, youthful appearance, energy levels, libido, immune function, kidney function, and female fertility to mention just a few.

Equally impressive are the corresponding decreases in insulin levels, skin aging, heart disease, cancer, diabetes, autoimmune disease, body fat, bone loss, free radical levels, and cortisol levels. The probability of most illnesses occurring is decreased, and if they do occur it tends to be at an older age.

It is important to remember that calorie restriction only provides these benefits if adequate nutrition is maintained. Dieting that results in malnutrition can, of course, be very harmful.

Scientists often use the term CRON diet. CRON is an acronym for calorie restriction with optimal nutrition.

Reducing calorie intake while still maintaining adequate nutrition requires careful attention. In future issues I'll show you some of the ways that scientists have found to accomplish this goal without experiencing hunger, but today I want to focus on some new research that was announced recently.

I don't think many people are prepared to engage in full-scale calorie restriction, but even a small step in that direction would be very beneficial to almost anyone. And I thought you might find this research interesting.

As I said before, scientist have long known that calorie restriction can greatly slow the aging process in laboratory animals, but they thought it had to be practiced from the time of birth. Then in the 1970's scientists at UCLA (Weindrich R., Walford RL, et al) showed that calorie restriction can accomplish this feat even if begun in middle age, provided that calorie intake is reduced gradually.

And now, on March 22, 2004, to be exact, Dr. Stephen Spindler and associated scientists at the University of California, Riverside, announced in the Proceedings of the National Academy of Sciences USA, research which shows that caloric restriction prolongs the life span of mice even when started very late in life, and the benefits begin almost immediately.

Their first study showed that in only two months of calorie restriction a three-fold reduction in age-associated mortality was achieved.

In their second study it was shown that mice that were put on a calorie-restricted diet at seven months of age showed the same patterns of beneficial gene expression as mice that had been put on calorie restricted diets at a very early age. And when these mice were taken off of the calorie-restricted diets, 90% of the beneficial gene expression was lost within eight weeks.

A lot of important new information such as the above is published every month in scientific journals. Much of this information never makes it to the general news media.

As a follow-up to our weight-loss and smoking-cessation programs, we are going to be passing along to you from time to time some of the more interesting and important new findings from these publications . If you have any questions, let us know, and I'll be happy to try to find the answers.

References:

1- Weindruch, R., and R. Sohal. 1997. Caloric intake and aging. N Engl J Med 337(14):986-94

2- Hursting, S.D., et al., "Caloric restriction, slowing aging, and cancer prevention: mechanisms of action and applicability to humans." Annu Rev Med 54: p131-52, 2003.

3- Walford, R.L., Harris, and M.W. Gunion. "The calorically restricted low-fat nutrient-dense diet in Biosphere 2 significantly lowers blood glucose, total leukocyte count, cholesterol and blood pressure in humans." Proc Natl Acad Sci USA 89:11533-11537 (1992)

4- Heilbronn, L.K. and E. Ravussin, "Caloric restriction and aging: review of the literature and implications for studies in humans" Am J Clin Nutr 78(3) 361-9, 2003

5- Kagawa, Y. "Impact of westernization on the nutrition of Japanese: Changes in physique, cancer, longevity, and centenarians," Prev Med7: 205-217 (1978)