It is possible the findings could apply to the human diet

The discovery, by scientists at Glasgow University, applies to zebra finches but experts believe the same could apply to humans.

Scientists found that birds with a low quality diet in the first two weeks of their lives developed fewer anti-ageing anti-oxidants and died sooner.

Anti-oxidants form part of the body's defence against ageing by reducing the damage caused by "free radicals".

Animals cannot make anti-oxidants, which include Vitamins A and E, and get them instead from their food.

'Shorter lives'

All the birds were fed unlimited quantities of birdseed, but in the case of some of the birds, this was of low quality and lacking in protein and vitamins.

Professor Pat Monaghan and Professor Neil Metcalfe, authors of the study, said at first glance they all grew up into apparently normal adult birds.

But they soon discovered the birds given the low-quality diet in infancy were then less able to make use of the anti-oxidants they had eaten, and had shorter lives.

Some birds were fed with low-quality bird seed

Prof Metcalfe said: "I think it's not yet clear whether the same things happen in humans, but it's possible.

"This mechanism is pretty common across species so it's possible.

"What is true is that early conditions are very important in later life."

In the case of zebra finches, he said, the two-week period covered by the survey was the equivalent to the first 10 years of a human being's life.

But Prof Metcalfe added that the junk food analogy is not exact.

"In the case of the bird food, the poor quality diet was low in vitamins and proteins - but human junk food is high in fat and can be high in protein", he said.