Washington, Nov 19 (IANS) How does going on a diet help fight ageing? Scientists have found some anti-ageing molecules that get activated by a low calorie diet.

Charles Mobbs, professor of neuro-science and geriatrics at Mount Sinai School of Medicine (MSSM), and colleagues unravelled a molecular conundrum to determine that in certain conditions, a lower-calorie diet slows the development of some age-related conditions such as Alzheimer's disease.

How the diet is restricted -- whether fats, proteins or carbohydrates are cut -- does not seem to matter.

Dietary restriction induces a transcription factor (DNA binding protein that turns genes on or off) called CREB-binding protein (CBP), which controls the activity of genes that regulate cellular function.

By developing drugs that mimic the protective effects of CBP -- those usually caused by dietary restriction -- scientists may be able to extend lifespan and reduce vulnerability to age-related illnesses, says an MSSM release.

The team found an optimal dietary restriction, estimated to be equivalent to a 30 percent caloric reduction in mammals, increased lifespan over 50 percent even as it slows the development of an age-related pathology similar to Alzheimer's.

These findings were published in the Nov 17 edition of Public Library of Science Biology.