New research from Aarhus University, Denmark demonstrates that specific milk proteins such as osteopontin can protect essential minerals through digestion and increase their absorption in the gut. This opens up new perspectives for ingredient development for infant formula and clinical nutrition.
The absorption of essential minerals such as iron and zinc is today often limited by so-called anti-nutrients – for example phytic acid, which is found in plant-based foods such as wholegrains, vegetables and legumes. Phytic acid binds the minerals in insoluble complexes, preventing the body from absorbing them effectively.
A new research project carried out at the Department of Molecular Biology and Genetics at Aarhus University points to a possible solution, however: milk proteins already isolated in dairy production could potentially help increase the absorption of these minerals.
Protecting minerals through digestion
The researchers examined the milk proteins osteopontin and α-lactalbumin and found that osteopontin in particular has a marked ability to bind large quantities of iron and zinc.
The project’s results show that the complex formed by osteopontin and minerals remains intact through the enzymes and changing pH levels of the digestive system. This means the milk protein functions as an effective carrier, protecting the minerals from phytic acid and delivering them directly for absorption in the intestinal cells. In trials using intestinal cell models, osteopontin showed significantly higher iron absorption compared with both α-lactalbumin and the well-known iron carrier lactoferrin.
According to the researchers behind the project, the results indicate that osteopontin in particular may play a role in the absorption of essential minerals, and that the protein could potentially be used in clinical nutrition and infant formula to increase mineral absorption.
Read more in Mælkeritidende no. 5, published on 21 August – or read the digital version of the research article (in Danish) HERE.
By Maja Løvstrup
Photo: mejeri.dk/Niels Åge Skovbo
