CALORIC RESTRICTION AND AGING AS VIEWED FROM BIOSPHERE-2

The low-calorie nutrient-dense diet consumed for 2 yr by the eight per sons sealed inside the closed ecological space known as Biosphere 2, n ear Tucson, AZ, constituted a unique ''experiment of nature,'' amounti ng to the first well-monitored application of a nutritional regimen pr oven in animals to substantially inhibit and delay time of onset of mo st age-related diseases, induce physiological changes characteristic o f a functionally ''younger'' age, and extend both average and maximum lifespans. Over the 2 yr the eight persons demonstrated a substantial weight loss, remarkable fall in blood cholesterol, blood pressure, fas ting blood sugar, and low white blood cell counts-exactly as seen in r odents on such a regimen. Studies in progress involving levels of cort isol, insulin, and glycosylated hemoglobin support the rodent similari ty. Further studies will seek to determine whether additional among th e large battery of physiologic changes induced in animals by calorie r estriction are also induced in humans on a similar nutrient-dense, cal orie-limited diet. Such evidence will pertain to the question whether the increased disease resistance and aging retardation shown by calori e-restricted rodents might also be expected to occur in humans.