Consuming diet very low in nutrients could extend lifespan in humans

A new evolutionary theory claims that consuming a diet very low in nutrients can extend lifespan in laboratory animals, a finding which could hold clues to promoting healthier ageing in humans.

Scientists have known for decades that severely restricted food intake reduces the incidence of diseases of old age, such as cancer, and increases lifespan.

"This effect has been demonstrated in laboratories around the world, in species ranging from yeast to flies to mice. There is also some evidence that it occurs in primates," lead author, Dr Margo Adler, an evolutionary biologist at UNSW Australia, said.

The most widely accepted theory is that this effect evolved to improve survival during times of famine.

"But we think that lifespan extension from dietary restriction is more likely to be a laboratory artefact," Dr Adler said.

The UNSW researchers' new theory is that this effect evolved to help animals continue to reproduce when food is scarce; they require less food to survive because stored nutrients in the cells can be recycled and reused.

It is this effect that could account for the increased lifespan of laboratory animals on very low-nutrient diets, because increased cellular recycling reduces deterioration and the risk of cancer.

"This is the most intriguing aspect, from a human health stand point. Although extended lifespan may simply be a side effect of dietary restriction, a better understanding of these cellular recycling mechanisms that drive the effect may hold the promise of longer, healthier lives for humans," she says.

The study is published in the journal BioEssays.