Mothers of small babies warned against danger of over-feeding

Infants who were fed milk enriched with nutrients had higher body fat mass than those who were given standard formula, according to the study.

Previous studies have shown a link between over-nutrition in childhood and overweight adults in animals, but the researchers said this was the first demonstration in humans when other factors such as the size of mothers is ruled out.

Body fat mass in five to eight-year-olds was 22 per cent to 38 per cent greater in those who were given nutrient-enriched milk as babies than those who had standard formula, according to a team based at the University College London Institute of Child Health.

The scientists said the findings, published online in the American Journal of Clinical Nutrition, have important public health implications as Britain tackles the problem of obesity and pointed out they confirm previous estimates that more than 20 per cent of adult obesity may be caused by over-nutrition or other early excessive weight gain in infancy.

Study leader Prof Atul Singhal, from the MRC Childhood Nutrition Research Centre, UCL Institute of Child Health, said mothers should breastfeed if possible.

“It’s easier to regulate appetite and harder to overfeed breastfed babies,” he said.

“If they can’t breastfeed they shouldn’t overfeed because babies should not put on too much weight too quickly.

“Small babies will put on weight faster than other babies anyway as they try to catch up.

“Mothers should not add fuel to the fire by giving them any more to try to make them heavier than their percentile.

“Parents need to relax more about the weight.”

Researchers looked at two randomised, controlled, double blind studies – where neither they nor the mothers knew which kind of milk they were assigned – involving small newborn babies in hospitals in Cambridge, Nottingham, Leicester and Glasgow.

Mothers who had no plans to breastfeed were given either standard formula milk or a formula containing extra protein, energy-boosters, vitamins and minerals.

In the first study, which was conducted on 299 babies between 1993 and 1995, the formula was used for nine months.

Researchers then measured the body fat of 153 (51 per cent) of the children in their homes between 1999 and 2002.

The second study involved 246 infants between 2003 and 2005 – until it was stopped early due to evidence of the link between early over-nutrition and later obesity – of whom 90 (37 per cent) were followed up to assess fat levels in 2008-09.

Prof Singhal added: “This study robustly demonstrates a link between early nutrition and having more fat in later life in humans – a finding suggested by previous studies and confirmed in many other animals.

“Our findings are strong, consistent, show a dose-response effect, and are biologically plausible.”

A spokesman for the Department of Health said: “Breastfeeding is the healthiest way to feed a baby.”