Dietary restriction and life span

A calorie restriction effect on longevity is a very well documented topic of experimental biology. It is important to know that life span researchers deal mostly with small size any meals since their generations change much faster than in larger size animal species. It is also important that only restriction as serious as 30 to 60 percent of "all you can eat" amount can cause significant improvement in health and longevity.

It was first demonstrated in insects, where it yielded up to a 300% increase in life span; then in young small size mammals such as mice and rats, where results were more modest but still impressive. Later the results on adult animals appeared, yet more modest, but still significant. As to the human outcome, published epidemiological studies have reported evidence of reduced mortality rates in persons who have lost weight, regardless of whether the weight loss was due to decreased calorie intake or increased energy expenditure (1). These data are consistent with experimental results where exercise increased average longevity of female rats, despite increased food intake (2).

This consistency is probably the reason for hopes arising from numerous animal data showing benefits of calorie restriction in animals, including improvement in immune status, anti-cancer defense system and decrease in the occurrence of general disease. The hope, if not for increased longevity, is at least for decreased mortality.

Can we use calorie restriction to improve health and to live longer? A daily calorie

restriction of 30 to 60 percent seems to be too hard a sacrifice. Perhaps this is why new hope arose when preliminary information about developing an anti-aging drug mimicking effects of semi-starvation leaked into mass media.

Dr. Masoro from the Department of Physiology and Aging Research, University of Texas, reviewed 54 scientific articles and concluded: "A spectrum of findings indicates that dietary restriction retards the aging processes of mice and rats. It also maintains many physiological processes in a youthful state and, most strikingly, retards or prevents almost all age-associated disease processes." (3) However, it's too soon to use the calorie restriction as a strategy to improve health and prolong life.

"Due to the interrelationships between disease and older age, and the limitations of existing research in this area, most life extension strategies are untested hypotheses. Many strategies merit scientific inquiry, but they cannot be recommended for use. More extensive research is necessary to assess their safety, effectiveness, and socio-economic impact, and to resolve ethical controversies before they can be considered applicable in humans." (Pharmacotherapy, 16(2):183-200, 1996)

More on the topic

Dietary restriction and life span

Can Adults Benefit from Calorie Restriction?

Is calorie restriction stressful?

References