Healthy diet in high-chair can boost baby hopes in later life

Those who are born into a time of famine and have mothers who are struggling to eat well, meanwhile, are less likely to reproduce at all.

The research, which has been published online in the journal Ecology, is the first study of its kind to show that the food taken in by children in their early lives can have a serious influence on their long-term fertility.

Researchers, led by Dr Ian Rickard from Sheffield University's department of animal and plant sciences, used a combination of church record data on births in 18th century Finland and agricultural data on crop yields of rye and barley from the same time and place.

They found that, for men and women born into poor families at the time, the food they ate in early life, through their mother, was linked to their probability of reproducing as adults.

Approximately half of the poor people who were born in a year in which both rye and barley yields were low would not go on to have any children during their entire lives.

However, almost everyone from a poor family born in bumper harvest years, when both crops were high, would reproduce at least once in their life.

These results, the researchers say, indicate that food received during prenatal or early postnatal life – ie while babies are in the womb or being breastfed – may limit the development of the reproductive system.

Dr Rickard said: "There's a quite a lot of evidence to show that people's environment in early life can have profound consequences when it comes to things like having Type 1 diabetes.

"One of the things we were interested in, though, was reproduction.

"Our results show that the food received by children born into poor families had an influence on their later reproductive success.

"These results have implications for our understanding of early environmental effects on human and animal health and will help shed light on our current understanding of fertility and whether it is influenced by individual or social factors."

The research was done using specifically poor people, Dr Rickard said, because children from less affluent families are more likely to be vulnerable to local food availability.

He said: "For babies born in poor crop years, only half would go on to reproduce, and for babies born in good crop years, most would reproduce.

"This is interesting because until now there haven't been many studies that have linked food to reproduction.

"However, this is not going to be as major a factor in populations now because things are very, very different."

Earlier this month, another expert from Sheffield University announced that he was set to investigate whether all the sperm that men produce is equally likely to lead to fertilisation.

The 1.7m research project, led by Professor Tim Birkhead, will look at the biological significance of the size and number of sperm different species produce.

It is hoped the findings of Professor Birkhead's study, which has been funded by a five-year European Research Council grant, could lead to improvements in assisted reproductive technology for humans.

He said: "If my research confirms that all sperm are not equal, the findings could be applied to humans."