Inborn errors of metabolism

Inborn errors of metabolism

Inborn errors of metabolism

Developing safe and effective proteins for PKU nutrition

Phenylketonuria (PKU) is what is known as an inborn error of metabolism – a rare genetic disorder that affects 1 in 10,000 to 15,000 people. Patients with PKU are unable to metabolise the amino acid phenylalanine, which is naturally present in all proteins.

If PKU patients consume a diet with a normal protein level, phenylalanine will accumulate in their blood and brain at toxic levels. If left untreated, high levels of phenylalanine can cause brain damage and intellectual disability in PKU infants and children.

Challenges of PKU nutrition

It is therefore crucial that PKU patients follow a restrictive, low-protein diet to keep phenylalanine levels within a healthy range. The PKU diet is based on low-protein foods combined with protein substitutes, which consist of artificial free amino acids devoid of phenylalanine. These free amino acid formulas often have an undesirable taste and smell. These issues can reduce the adherence of patients to protein substitutes. In contrast, the natural polypeptide, CGMP, has a neutral taste and smell that improves palatability of protein substitutes1. This can be beneficial for improving adherence to the rigorous diet of patients with PKU.

Better nutritional options with whey

Arla Foods Ingredients has collaborated with leading experts for more than a decade to develop better nutritional options for PKU patients. The focus is Lacprodan® CGMP-20 – our whey-derived, highly purified casein glycomacropeptide (CGMP) product.  Lacprodan® CGMP-20 is a suitable protein source for PKU patients due to its very low content of phenylalanine. In foods for PKU nutrition, it can replace a large share of the free amino acids and provide nutritional benefits, such as stabilising circulating phenylalanine levels in patients with PKU2.

It is essential that we continue to build up the scientific evidence and discover the full health benefits of CGMP in PKU nutrition. At Arla Foods Ingredients, we have a team of dedicated nutrition scientists who collaborate closely with universities and research partners to find the most suitable protein sources for PKU patients. We also welcome collaborations with our customers to document the health benefits of CGMP and develop further high-quality and effective foods for PKU diets.


1. Daly, A., et al., Glycomacropeptide in PKU-Does It Live Up to Its Potential? Nutrients, 2022. 14(4).

2. Daly, A., et al., The Effect of Glycomacropeptide versus Amino Acids on Phenylalanine and Tyrosine Variability over 24 Hours in Children with PKU: A Randomized Controlled Trial. Nutrients, 2019. 11(3).


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