UW finds better alternative to protein replacement

by Carolyn Potts

Tuesday, February 5, 2008 22:31

People suffering from a diet restricting disease will soon have an alternative to the foul-tasting concoction that replaces protein in their diets, thanks to researchers at University of Wisconsin.

Individuals inflicted with phenylketonuria must severely restrict their intake of protein, including meat, fish and cheese because they lack the enzyme required to break down phenylalanine, one of 20 major amino acids that form the proteins in everyday foods, according to a UW statement.

Small amounts of phenylalanine are required for life, but excess amounts interfere with brain function. However, those who go off the special diet often suffer from concentration problems and depression, and may even sustain permanent brain damage, said Denise Ney, UW nutritional sciences professor.

With a grant to research whey, a byproduct of cheese-making, UW food engineer Mark Etzel unexpectedly found a safe form of protein that could significantly improve the diets of people diagnosed with PKU, Ney said.

“So far, the [whey] treatment is the only protein that doesn’t have high levels of phenylalanine,” Ney said.

According to the UW statement, the unpleasant taste of the amino acid drink that provides most of PKU patients’ protein is a major reason many struggle to drink enough to meet their doctor’s prescriptions, roughly two to three cups a day.

“This should make it much easier for these people to stay on their diets,” Ney said. “The amino acid formula that most of their protein comes from has a very strong taste.”

Researchers at the Wisconsin Center for Dairy Research have begun creating products that contain glycomacropeptide, a protein found in whey that is phenylalanine free. Although it is not the best quality protein, these foods will help to supplement the amino acid concoction and will decrease the amount people with PKU will have to drink, the statement said.

“We have a variety of foods,” Ney said. “We have sports drinks and milkshakes, pudding, crackers and fruit roll-ups. We are also working on a puffed breakfast cereal.”

Because glycomacropeptide is a food ingredient currently sold by two different companies on the market, it has already been deemed safe for consumption. This makes Ney’s research a lot easier because there won’t be a wait for approval by the FDA.

Ney applied for a grant Monday to conduct large-scale human clinical trials. The request is for more than $2 million and will allow researchers to test a diet with the new products on patients with PKU in four different locations across the country.