Age gracefully with low calorie diets

The study conducted at Harvard T.H. Chan School of Public Health suggested that Targeting mechanisms in the central nervous system that sense energy generated by nutrients might yield the beneficial effects of low-calorie diets on healthy aging without the need to alter food intake.

The study focused on a molecule called "AMP-activated protein kinase," or AMPK, which acts as a molecular fuel gauge to detect energy levels. It's been known that AMPK plays important roles in all cell types, but researchers didn't understand which of these activities were most critical to regulating longevity.

The researchers found that AMPK inhibited the activity of a protein called CRTC-1 in neurons. This process, in turn, controlled the behavior of mitochondria the primary energy-producing organelles in cells throughout the organism, by altering production of a neurotransmitter. The researchers were struck by the fact that altering the AMPK pathway in just a limited set of neurons was sufficient to override its effects on metabolism and longevity in other tissues. Aging was influenced more by what the animals perceived they were eating than what they actually ate.

The study suggested that manipulating this energy-sensing pathway can cause organisms to perceive their cells to be in a low-energy state, even if they are eating normally and energy levels are high. Drugs targeting the cells' energy-sensors in this way could potentially address age-related diseases, including cancer and neurodegeneration, and may offer an alternative to caloric restriction.

The study is published in the journal Cell.