Colossal kid may hold key to muscle

At five years old, he can lift seven-pound dumbbells with arms extended. He possesses twice the normal muscle density and half the body fat for his age. What kind of protein shakes is mum feeding him?

Unfortunately, it's all genetic, as five years of scientific investigation has uncovered. It was in 1999 that doctors first studied the German infant, amazed at his unusually noticeable upper arm and leg muscles. Concerned for his health, the medics tracked the bulging baby's development for five years, reporting their findings in the recent New England Journal of Medicine.

DNA analysis revealed the cause of the muscle growth. Myostatin is a protein produced by the body to regulate the growth of muscles. Scientists found that the baby had a genetic mutation that shut down myostatin production, allowing freer rein for muscles to grow.

The boy's herculean heritage includes a somewhat muscular mother (a 24-year-old former professional sprinter), her brother and three other close male relatives, all reported to be unusually strong. Unlike his relatives, the boy was found to have two mutated copies of the gene.

This is the first time a human has been identified with the mutation. In 1997, Belgian Blue Cattle, a particularly muscular breed, were found to have the gene. Since then, doctors have been keen to explore the possibilities of myostatin blockade in treating HIV, muscular dystrophy, obesity and diabetes.

But after news of the muscle-controller first broke, it wasn't long before bodybuilding supplements, claiming to block myostatin, surfaced on the black market. The supplements to date have been widely dismissed both within the scientific and bodybuilding communities as useless and potentially harmful. Scientists predict the recent human discovery will reignite commercial interest in myostatin-blocking agents.

"Myostatin blockade will probably work its way into professional and amateur athletics, as well as into the ever-growing business of physical enhancements," Elizabeth McNally of the University of Chicago, Illinois, reported in the New England Journal of Medicine.

Wyeth, a pharmaceuticals company in Pennsylvania, has created a protein that disables myostatin and is conducting a human safety trial of the substance. The company has a patent on all human therapeutic uses of myostatin and plans to make muscular dystrophy its first focus.

But the good news is you don't have to be a genetic freak, nor a pharmaceutical guinea pig, to naturally suppress myostatin. Nutritionist Luke Summers says there is still hope for ordinary muscle babies.

"Myostatin tends to correlate with cortisol release, so most of the basic measures that help keep cortisol low are likely to also keep myostatin in check," Summers said.

"Regular exercise, for example, will help contain myostatin, whereas overtraining would stimulate high levels. Infrequent eating can also result in high myostatin as the body focuses on breaking down muscle protein for more important needs.

"Some believe glucosamine supplementation has a binding effect that helps block myostatin, but this is yet to be conclusively demonstrated."

Summers said it's important not to think of myostatin as the "bad guy" in muscle development.

"The problem with having to lug around surplus muscle tissue is that it works against the body's ultimate aim, to be as efficient as possible. Without myostatin, your weight training efforts would be a constant stimulus for unbridled muscle growth, which sounds great up until the moment you split like an overripe grape. Myostatin ensures optimal muscle size in relation to strength and activity."

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