Food for thought

We used to call it puppy fat. If you were a fat toddler, you wouldn't necessarily become a fat adult: now, you probably would," says Dr Atul Singhal, a consultant paediatrician and advisor to the UK's Infant and Toddler Forum, set up last year to supplement health professionals' diet of glossy nutritional advice from manufacturers with some impartial, albeit less consumer-friendly science.

But is the telly tubby generation really doomed to an obese middle age and, if so, must mums take the blame, or is formula milk the real culprit?

According to Earnest, the nickname for the EU's Childhood Obesity Programme, which earlier this year linked faster growth rates among babies fed high-protein formula with later obesity, what we eat in the first six months can determine our future health and life expectancy. Get it wrong, and your child could be on a one-way ticket to high blood pressure, type-2 diabetes and cardiovascular disease, potentially fatal disorders known as the metabolic syndrome that are threatening to logjam doctors' surgeries across Europe.

"While you get a heart attack in your 50s or 60s, the process is continuous almost from birth," says Singhal, who is conducting one of 20 randomised trials on 1,000 infants in Europe in the hope of decoding what's known as early nutrition programming. "The faster a baby grows in the first six months, the more likely that person will be obese in adulthood," he says. "We don't know what's going on in the body but it's a hypothesis seen in every animal species: if you promote growth you have a much shorter lifespan."

Size matters

Singhal would like to see a change in thinking among health workers "obsessed with making babies bigger", an across-the-board lowering of protein in formula milk and urgent revision of baby growth charts that for more than a decade have taken the rapid weight gain displayed by formula fed infants as the norm. Earlier this year, Munich University's Bert Koletzko, who heads up Earnest, blamed the charts for creating "avoidable obesity", while the World Health Organisation is now canvassing paediatric opinion on revised growth guidelines based on a study of 8,500 breastfed babies.

But the dietary rot could be setting in even earlier, warns Lucilla Poston, professor of maternal and foetal health at the baby charity Tommy's and director of division, reproduction, and endocrinology at King's College, London, where researchers are about to embark on the first study into the effect pregnant women's food choices have on the future welfare of their offspring.

The study may help to explain the enigma of the 'u-shaped curve', a statistical tendency for small and heavyweight babies to show the same diet-related problems, whether mum was skinny or obese. "We think the mechanism at work is quite similar," says Poston. The theory is that whatever a baby's birthweight, if it emerges from a nutritionally impoverished environment in the womb into a world of comparative plenty, the famine to feast experience will press the countdown button to metabolic syndrome, especially when babies are encouraged to play catch-up fast.

While results of trials in India show the theory has legs, Poston's studies concentrate on the nutritional balance of obese women in the developed world - predicted to represent 25% of the UK's pregnant mums alone by 2010 - and their often oversized juniors.

"If the women have a low-GI (glycaemic index) diet they will avoid surges in insulin and glucose and it's the glucose that makes the children grow. If you can get them to adopt a diet in pasta and fruit and to stay away from white bread and cakes, saturated fat is not so much a problem."

She sees an opportunity for manufacturers to identify foods for pregnant women. "Towards the end of the study we will be working with manufacturers to market advice and help women make choices," says Poston, who has already talked to major supermarkets about labelling pregnancy-friendly foods. "It's something they are taking quite seriously, but it's a long way down the line."

Nutrient deficiency

Poston's study will move the debate on, especially among sceptics, like Singhal, who argue that it's post-natal feeding rather than experiences in the womb that dictate your food choices as an adult. Others, meanwhile, are busy unravelling the mechanics of the placenta and the complex chemical signals that might predispose a child to dietary disease.

At the Rowett Institute in Scotland an artificial placenta could shed light on how the real thing copes with deficiencies in the mother's diet and how nutrients, such as copper and iron, interact. Already it has shown that mothers who fail to eat a balanced diet panic the placenta into evasive action: within an hour of detecting shortages of any one nutrient, it has installed a rapid transport system to speed up delivery of amino acids, the building blocks of life, to the foetus. "This could have evolutionary advantages, since it is likely that one nutritional restriction would not happen on its own, so iron deficiency would be associated with amino acid restriction, if not immediately, then soon," the researchers conclude. They believe putting the placenta under such stress can have a significant impact on foetal development.

"It is also clear that the effect of any one nutrient is much more widespread than previously thought," says Rowett's Professor Harry McArdle.

This could explain a 2003 Nepalese study that demonstrated taking folic acid boosts the effect of iron supplementation in pregnant women, reducing anaemia by 54%, but taking zinc or multiple micronutrients appeared to diminish it.

Not only would McArdle's team like to see iron supplementation "more or less in parallel with folate supplementation" but it would also like advice refined on the best time to take supplements. "For example, an iron supplement is generally recommended in the last trimester so that iron can be transferred to the baby and stored for after birth, when iron intake is quite low. But we would suggest that the early period is also as important because the foetus needs iron, not so much as a nutrient, but for cell growth and development."

Links between micronutrient deficiency and problems in childhood are well documented. "Offspring of iron deficient mothers become obese. That's showing up quite clearly. Rats born to mothers given a low-protein diet have higher blood pressure and babies born to mothers with an unbalanced diet, have a sensitivity to unbalanced diet later," says McArdle. But influencing outcomes is a different matter.

The Children of the Nineties study, co-ordinated by Bristol University, UK, has already rubbed up against World Health Authority advice for mothers to continue breast feeding until their babies are six months old. Not only does that miss crucial chances to introduce foods that will lay the foundation for healthy eating in later life, but it has also stymied advice on other feeding regimes, according to the project's head of nutrition, Pauline Emmett.

Worryingly, her studies show that 13% of UK mothers are feeding cows' milk by eight months. This risks anaemia because it is much higher in calcium, which antagonises the absorption of iron in the gut.

"People doing the right thing are all well educated. The least educated have less money and they perceive healthy eating as more expensive. They don't have the cooking skills or confidence in what they think is right," says Emmett.

And what's right has not been helped by received dietary wisdom over the past decade, according to Gillian Harris, a paediatric psychologist at Birmingham Children's Hospital.

"When you look at weaning foods, most of them start with a rusk or a biscuit. How many green or red foods do we give them?"

It's not surprising then, she says, that, for most kids, the default binge in later life is "beige carbs", an endless diet of chips, bread and crisps.

"A lot more money should be spent on promoting foods in their first year," says Harris.