Navigation Links
Unique whey protein is promising supplement for strict PKU diet
Date:2/4/2008

MADISON Individuals with a rare genetic condition known as phenylketonuria, or PKU, receive a difficult-to-follow prescription. They must severely limit their consumption of protein, completely avoiding mealtime staples such as meat, cheese and even bread. Not surprisingly, for many, diet is a constant struggle.

In an effort to expand their dietary options, a team of University of Wisconsin-Madison scientists is assessing a unique protein found only in whey, the liquid byproduct of cheese-making, that appears to be safe for this group to eat. As published today in the Journal of Nutrition, the team found that this proteinwhen supplemented with a few amino acidssupports the growth of young, normal mice. More importantly, mice with a version of PKU fared well on this whey protein diet and had relatively low levels of PKU-associated toxins in their brain tissue and blood.

These findings open the door to the possibility that individuals with PKU will be able to eat foods enriched with the whey protein.

We did these studies in mice to show that (eating this protein) is going to be feasible in humans, says Denise Ney, a professor of nutritional sciences who headed up the study, which was funded by the UW-Madison Graduate School and the U.S. Department of Agriculture. Its so important to individuals on this diet to have new options, to have their diet liberalized. Its a quality-of-life issue.

There are around 15,000 people in the United States with PKU. From birth, they lack the enzyme responsible for breaking down phenylalanine, one of the 20 major amino acids that form the proteins we eat in everyday foods. They must avoid protein because, while small amounts of phenylalanine are required for life, excess amounts stay in their bodies indefinitely and interfere with brain function. Those who go off-diet often suffer from concentration problems and depression. A few even sustain permanent brain damage.

Instead of eating protein directly, people with PKU drink a foul-tasting cocktail of amino acids to meet most of their bodys daily protein needs. It tastes so bad that many struggle to drink enough to meet their doctors orders.

Ney hopes to reduce reliance on this cocktail by offering an alternativefoods and beverages made with glycomacropeptide, the only known dietary protein that is phenylalanine-free. Mark Etzel, a UW-Madison food engineer and fellow co-author on the paper, developed a method to purify this unique protein from cheese whey.

Glycomacropeptide is lousy from the standpoint of protein quality. It doesnt have the right proportion of essential amino acids, says Ney. However, we show that by supplementing it with the right amino acids, the mice grow just fine. This establishes the nutritional adequacy of this diet.

Her team also looked at the brains of mice with PKU, where phenylalanine causes problems. Perhaps the most interesting observation about the mice that were fed glycomacropeptide is that they had a 20 percent decrease in phenylalanine in their brains (compared to those fed the equivalent of the traditional amino-acid diet prescribed to humans). Thats a pretty good drop, and we saw it consistently in five different areas of the brain.

Phenylalanine was also lower in the blood of these mice, by about 11 percent.

Upon learning about these positive results, various grassroots organizations that support the PKU community decided to fund this project, helping the UW-Madison team move more quickly in the direction of real-world applications. Already, Kathy Nelson, a researcher at the Wisconsin Center for Dairy Research, has created a line of glycomacropeptide-fortified foods, including pudding, fruit rolls, crackers and an assortment of flavorful drinks. Prototypes are currently being tested in a human clinical study funded by the National Institutes of Health, and the preliminary results look promising, says Ney.

In the future, Ney thinks this protein could replace about half of a persons daily dose of the amino acid drink. Most people with PKU drink two or three cups per day. By consuming a glycomacropeptide-fortified pudding cup, fruit roll or sports drink, they may be able to drink just one or two.

This is exactly what Ann Zimmerman of Middleton, Wis. would like to see. Her 10-year old daughter Jessica recently began refusing to drink her amino acid drink at school, after getting teased a few times. While we wait for treatments that address the underlying problem of PKU, says Zimmerman, glycomacropeptide is what we need.


'/>"/>

Contact: Denise Ney
ney@nutrisci.wisc.edu
608-262-4386
University of Wisconsin-Madison
Source:Eurekalert

Related biology news :

1. A unique arrangement for egg cell division
2. Scientists spy enzyme that makes us unique
3. A unique experiment with chlorine -- and a new way of teaching
4. Unique pattern of gene expression can indicate acetaminophen overdose
5. Starters orders for unique Ph.D.s in sport
6. Unique porous copper structure enables new generation of military micro-detonators
7. Unique fungal collection could hold key to future antibiotics
8. Protein chatter linked to cancer activation
9. Scientists link fragile X tremor/ataxia syndrome to binding protein in RNA
10. Researchers identify proteins involved in new neurodegenerative syndrome
11. Low levels of key protein may indicate pancreatic cancer risk
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:8/23/2017)... N.Y. , Aug. 23, 2017  The general public,s help is ... human microbiome—the bacteria that live in and on the human body –and ... The ... in the human microbiome, starting with the gut. The project's goal is ... disease. Photo credit: IBM ...
(Date:7/20/2017)... -- Delta (NYSE: DAL ) customers now can use fingerprints ... Washington National Airport (DCA). ... Delta launches biometrics to board aircraft at Reagan Washington National ... Delta,s biometric boarding pass experience that launched ... into the boarding process to allow eligible Delta SkyMiles Members who are ...
(Date:6/23/2017)... and ITHACA, N.Y. , ... and Cornell University, a leader in dairy research, today ... bioinformatics designed to help reduce the chances that the ... the onset of this dairy project, Cornell University has ... for Sequencing the Food Supply Chain, a food safety ...
Breaking Biology News(10 mins):
(Date:10/12/2017)... ... October 12, 2017 , ... They call it the ... network, a depiction of a system of linkages and connections so complex and ... professor of computer science at Worcester Polytechnic Institute (WPI) and director of the ...
(Date:10/12/2017)... ... 12, 2017 , ... AMRI, a global contract research, development ... patient outcomes and quality of life, will now be offering its impurity solutions ... new regulatory requirements for all new drug products, including the finalization of ICH ...
(Date:10/11/2017)... Alto, CA, USA (PRWEB) , ... October 11, 2017 , ... ... set to take place on 7th and 8th June 2018 in San Francisco, CA. ... policy influencers as well as several distinguished CEOs, board directors and government officials from ...
(Date:10/11/2017)... ... 11, 2017 , ... A new study published in Fertility ... fresh in vitro fertilization (IVF) transfer cycles. The multi-center matched cohort ... After comparing the results from the fresh and frozen transfer cohorts, the authors ...
Breaking Biology Technology: