In this article it was speculated that calorie restriction reduces the production of free radicals. We have found that food deprivation almost doubles concentrations of melatonin in various parts of the gastrointestinal system. Melatonin, a very potent scavenger of free radicals, has increased the lifespan of mice in several studies. It could be that the increase in longevity of mice, rats, and dogs kept on a calorie-restricted diet is due to increased melatonin in the digestive tract.

George A. Bubenik
University of Guelph, Ontario