San Francisco Examiner, 16April1996
By Lauren Neergaard
Associated Press

WASHINGTON -- A dietary supplement developed for use in cattle feed appears to help male athletes build twice as much muscle as exercise alone, Iowa State University scientists report.

It's too soon to know all the effects of HMB, which the body naturally produces every time a person eats protein. But clinical trials involving large supplements of HMB are generating excitement among fitness buffs. The supplement's distributor even claims to have sold it to some Olympians and professional football players.

"If you take HMB and a bag of potato chips and sit on a couch, you're not going to see any effects," cautioned Iowa State veterinarian Steven Nissen, who presented his research to biologists meeting Monday in Washington.

But combined with exercise, 3 grams of HMB a day -- the amount derived if anyone could stand eating 500 grams (almost 1 1/4 pounds) of meat -- helped men develop more muscle and lose more fat, he said.

Is HMB, known chemically as beta-hydroxy methlylbutyrate, more than just another dietary supplement fad? Time will tell, said Elizabeth Applegate, a researcher at UC-Davis, who had not seen Nissen's results.

She noted, though, that researchers had long touted high protein diets for athletes, and specifically a protein amino acid called leucine. HMB is a metabolite -- a product of the metabolization -- of leucine.

"We're becoming more sophisticated" in searching for muscle-building aids, Applegate said. "First we eat meat, then we take amino acids, now we're taking metabolites of amino acids."

HMB appears safe but needs more research to prove how it affects muscle, added Rick Sharp, sports medicine director for the U.S. Olympic swimming team, who is following Nissen's research.

Nissen discovered HMB in 1988 while searching for ways to grow leaner cattle. Too much leucine was required to make supplements feasible, so he looked at leucine's byproducts. HMB apparently is the metabolite responsible for leucine's muscle-building effects.

A colleague at Vanderbilt University, who was interested in the human metabolism of protein, in 1991 tested HMB in 20 regular exercisers. The half who took HMB build more muscle than those who took dummy pills, so Nissen set out to prove that result wasn't a fluke.

He unveiled his fifth and largest clinical trial Monday. Forty men ate 3 grams of HMB or a placebo daily while undergoing strenuous exercise for four weeks. The HMB takers increased muscle by 3.1 percent and lost 7.3 percent of body fat, while those on placebo built only 1.9 percent more muscle and lost 2.2 percent of body fat.

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