By Polly Curtis

London (Guardian News Service): Use of hormone could be only 10 years away - Research raises medical, legal and ethical questions

British scientists are working on a baby formula which would chemicallyrestructure the metabolic system of children to ensure they never becameobese.

Studies in mice have found that large doses of the appetite-controllinghormone leptin during infancy permanently prevent excess weight gain andreduce the chances of type 2 diabetes.

Now researchers at the University of Buckingham say a leptin-enrichedbaby milk which does exactly the same is less than 10 years away, raising aplethora of medical, legal and ethical questions.

Other specialists in the field condemned the search for a medical answerto obesity, saying it is a modern social ill and that people need toaddress their lifestyles, not look for an artificial quick fix.

More suggested the translation to baby food would be impossible aspeople would not put their children forward for trials of the formula whenthey did not know the risks involved.

The research is reported in the journal Chemistry and Industry today.

Leptin turns off appetite throughout life, but the scientists last yearproved that high doses in mice through pregnancy and early life permanentlyreduced weight. They now believe it plays a role in hard-wiring the brain'sappetite response in infancy.

Mike Cawthorne, who led the researchers, said: "The supplemented milksare simply adding back something that was originally present: breast milkcontains leptin and formula feeds don't.

"Yes, it raises ethical questions. Obesity is a social problem, but it'salso a health problem which costs us millions of pounds a year and isgetting worse. It's not just a social problem.

"New ideas always face scepticism, but I think this is very, very likelywithin several years' time."

Previous experiments in treating obese people with leptin have failed aspeople continued to overeat. And though some research has linked bottle-fedbabies to childhood obesity, none has concluded that breast-fed babiesresist obesity throughout life.

Nick Finer, clinical director at the Wellcome Clinical Research Facilityat Addenbrookes Hospital, Cambridge, said: "The concept that addingsomething to a food that could permanently alter brain development isexciting but at the same time so scary that it would mean a wholly newapproach about how such treatments can be tested and approved for use.Would the first trials be in newly born children?

"The importance of leptin (and other hormones) at determining thedevelopment of brain circuits that control energy balance is an area ofcurrent research interest. The leap to a functional food being effective orsafe is enormous."

Stephen O'Rahilly, head of the Diabetes, Obesity & Insulin Action departmentat Cambridge University, described it as "science fiction". FrancescoCappuccio, professor of cardiovascular medicine and epidemiology at WarwickUniversity said: "Leptin is very easily destroyed by stomach acids so I'mnot sure how they think they will get it ingested through baby milk."

Prof Cawthorne, whose work is being funded by a government research counciland a private individual who has no connections with industry, said babiescould ingest leptin because their digestive systems were less developed.

Whether or not infant formula with leptin should be classified as a foodor medicine was a question that would have to be resolved, he said.

"It is still a grey area," he added. "One could argue that as you'rereplacing something that should be there, it's not pharmaceutical."

A spokesman for the UK?s Food Standards Agency said: "If you make afunctional food using ingredients that are already on the market, then youwouldn't have to go through a safety assessment. But if it includes newingredients then you would, and it depends on the sort of ingredients."