Press Release, 03.12.2009

The correct combination of proteins is decisive for healthy ageing, not reducing the calories in our diet.

A new study of the Max Planck Institute for Biology of Ageing could help to understand the positive effect of dietary restriction on healthy ageing. Previous evidence from different organisms (the fruit fly and mouse) have shown that dietary restriction increases longevity, but with a potential negative side effect of diminished fertility. So the female fruit fly reproduces less frequently with a reduced litter size on a low calorie diet, but its reproductive span lasts longer. This is the result of an evolutionary trait, as scientists believe: essential nutrients are diverted towards survival instead of reproduction.

If the health benefit stem from a reduction on specific nutrients or calorie intake in general, researchers of the newly founded Max Planck Institute for Biology of Ageing (Cologne) - currently still working at the University College, London - studied in manipulating the diet of female fruit flies. The results will be published today in the journal Nature.

The fruit flies were fed a diet of yeast, sugar and water, but with differing amounts of key nutrients, as vitamins, lipids and amino acids. The scientists could show that longevity and fertility are affected by the combination of type and amount of amino acids; whilst varying the amount of the other nutrients had little or no effect. Furthermore the researchers found out in previous studies that levels of a particular amino acid – methionine – were crucial to increasing lifespan without decreasing fertility. In carefully manipulating the balance of amino acids both lifespan and fertility were maximised. For the first time, this indicates that it is possible to extend lifespan without wholesale dietary restriction without lowering reproductive capacity.

As the effects of dietary restriction on lifespan is evolutionary conserved - observed in different organisms - researchers believe that the essential mechanisms apply to it as well. Even though the human genome has about four times the number of genes as the fruit fly, there are many similarities on genetic levels, which let these results turn out to be significant for human biology too.

Honour of 'Dame Commander of the Order of the British Empire' for Prof. Linda Partridge