Going for the Copper

Aug. 11–Joseph Prohaska has heard the question many times: Why study copper?

“We like to call it the Rodney Dangerfield of the elements because it doesn’t get much respect compared to the other trace elements,” he said.

Dangerfield, the late comedian, made a show business career out of a fruitless search for respect.

Professor Prohaska has made a 35-year career out of a fruitful search for the role copper plays in human nutrition, finding it plays a critical role in early development.

That search has taken the 60-year old professor in the Medical School at the University of Minnesota Duluth to the frontier of scientific knowledge.

“He’s one of the premier researchers in the copper field,” said Jack Saari, a scientist at the Grand Forks Human Nutrition Research Center, one of six such centers operated by the U.S. Department of Agriculture.

Saari, who also specializes in studying copper and nutrition, said Prohaska’s name rightly belongs on a top-five list of experts in the field.

“He’s probably even closer to the top than that indicates,” Saari said.

Copper is one of the trace elements — iron, zinc and manganese are some others — that humans need in minute quantities to power the internal cellular processes necessary for life.

Dietary copper is crucial to the function of certain proteins called enzymes, which promote biochemical reactions within cells. Enzymes, for example, aid digestion, starting with an enzyme in saliva that begins breaking down big molecules in the food we chew into smaller molecules.

Humans contain about a dozen enzymes that need copper to work properly, and that’s why we need to ingest some copper every day, Prohaska said.

But not much. In 2001, the National Academy of Sciences lowered its recommended dietary allowance for copper — the RDA numbers are often printed on vitamin bottles — to just 0.9 of a milligram a day. A standard aspirin tablet is 325 milligrams.

“So this is truly a trace element,” Prohaska said.

Drinking water supplies tiny amounts of copper, and copper is widely distributed in the food supply. Copper-rich foods include organ meats, shellfish, mushrooms, chocolate, soy and bran products, just to name a few.

It would be very difficult to find adults in Duluth or elsewhere who are copper deficient because a normal diet is almost certain to supply enough, Prohaska said. But the 0.9 mg recommendation is aimed at the general population.

“I’m interested in copper during early development,” Prohaska said.

And that’s the story unfolding in his laboratory on the second floor of UMD’s School of Medicine Building. Prohaska has been able to show that baby rats deprived of copper for very brief periods while breast feeding never attain the motor skills of rats who get adequate copper.

The deprivation only lasted a few weeks, after which the rats ate a copper-rich diet for a year.

“And yet, there was an impact on brain development,” Prohaska said. “That was a pretty significant discovery.”

The discovery has important implications for human nutrition.

“If you can extrapolate that to the human situation, if we didn’t get enough copper during early development, then we would have minimized our opportunity to achieve full physical and cognitive function,” Prohaska said.

The biggest concern: Teenage girls who become pregnant. “Their diets are lousy,” he said. “They’re one of the few population groups that we know don’t take in enough copper.”

Breast milk of copper-deficient mothers may not supply adequate copper to infants. Research with rats also suggests that the last third of gestation is the period when the preborn gets most of its copper from the mother.

“A teenage girl, delivering prematurely and not having enough to eat — then that baby is really at risk for having a (copper) deficiency,” Prohaska said.

His success has brought millions in research grants to UMD. Grants are the lifeblood of scientific research. They’re earned in an intensely competitive system of proposal writing.

Earlier this year, Prohaska won two grants from the National Institutes of Healthtotalling $950,000 for continuation of his research.

“I feel extremely blessed that I was able to pull this off,” he said.

Five others — two undergraduates, two graduate students and an assistant scientist — work under Prohaska’s direction.

Anya Gybina, a Ph.D. candidate in biochemistry, is one of Prohaska’s assistants.

“What we’re getting here is good experience in basic research,” Gybina said.

Prohaska credited his students with much of his success.

“They do the work,” he said. “I just have to write it up.”

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