Numerous studies have shown that what we eat is vital to our health. New research suggests that when we eat may be just as important.
In mice, as in people, blood sugar concentration rises to a peak once a day. Mealtimes strongly influence this daily oscillation in blood sugar, or glucose, concentrations.
Previous studies have shown that when researchers damage an area of a mouse's brain known to regulate circadian rhythm, the body's 24-hour time clock, the rodents stop regulating blood sugar concentrations. To determine whether circadian-clock genes play a direct role in controlling blood sugar, Garret FitzGerald of the University of Pennsylvania in Philadelphia and his colleagues examined mutant mice in which either of two such genes, known as Bmal1 and Clock, was impaired.
Unlike normal mice, the mutants had no daily spike in blood sugar concentrations. When the researchers injected the mutant mice with insulin, which normally knocks down bloo