Most of our free radical production comes from the energy-producing activities in the cell organelles known as mitochondria. The rate of mitochondrial damage could be a key factor in determining the rate of aging. Calorie restriction translates into lower levels of free radical production in the mitochondria. But other physiological phenomena associated with calorie restriction are also likely to play a role in promoting longevity. Dr. Mark Lane of the National Institute on Aging in Baltimore presented a summary of the effects of calorie restriction.
Calorie restriction is known to reduce serum glucose and insulin levels.
Both of these typically rise with age and age-related increased obesity. High glucose levels lead to the formation of harmful glycation products as glucose cross-links with body proteins such as collagen. Elevated insulin in turn has a number of harmful effects, including more production of inflammatory prostaglandins, which suppress the immune response, among many other negative consequences. Dr. Lane stressed that there is a huge difference in baseline insulin levels between old calorie-restricted animals as compared to controls. The lowering of serum glucose and insulin is one of the earliest and most dramatic results of calorie restriction, and is perhaps the primary way in which calorie restriction works to extend life span.