BioEd Online

The World Health Organization (WHO) has issued new guidelines showing how babies should ideally grow. Controversially, the new charts mean that more children in Western countries could be labelled as overweight.

Doctors and parents already use charts to gauge if kids are gaining height and weight healthily. But they have flaws; they were drawn up in the 1970s and based on surveys of American children, when most babies were fed formula rather than the breast milk recommended today.

The WHO's new Child Growth Standards are designed to show how children from birth to age 5 should grow when given a model healthy start in life. Researchers selected 8,440 children from Brazil, Ghana, India, Norway, Oman and the United States who were breast-fed, received good medical care and had mothers who did not smoke. They collected information on their height, weight and other growth milestones over 5 years.

The WHO team members say that they want national health organizations, doctors and parents to adopt the new standards in order to recognize signs of poor nutrition or obesity as soon as they rear their head.

"I would say it's an extremely important event in the history of growth monitoring," says Tim Cole, a professor of medical statistics at the Institute of Child Health in London, who was on the steering group for the standards. "It's vastly better than anything that's come before."

Big babies

One major finding from the study is that children from all corners of the globe follow almost exactly the same growth trajectory. This lays to rest the idea that genetic differences make the babies of some ethnic groups bigger or smaller than others. It shows instead that different populations tend to grow the same when given the chance.

In Western countries, the new charts could also show that as many as 20-30% more children should be classed as overweight, because breast-fed children tend to be leaner and grow more slowly than the formula-fed babies represented by the old growth references. "It's going to be very controversial," says Frank Greer, a member of American Academy of Pediatrics' committee on nutrition. "There will be more babies off the curve."

Some specialists say that the old references may have contributed to the rise in child obesity because breast-feeding mothers were inappropriately advised to add formula or solid food when their children seemed to be underweight.

Over or under?

Greer says that there will now be debate among experts in the United States about whether to adopt the WHO standards, because so many children are formula-fed in that country. If many such babies are on the heavy side of the new standards, it might cause parents to worry that their children are overweight. But it is unclear, Greer says, how to change formula feeding in order to slow growth, or whether this difference in weight causes any major health problems over the long term.

Cole disagrees. He points to mounting evidence that babies who grow very quickly in the first year may be at increased risk of chronic diseases later in life, such as obesity and heart disease. The new standards would serve as a red flag for children at risk, he says: "It's critical that these ballooning babies get some feedback."

Visit our newsblog to read and post comments about this story.