PROBONE – Role of dairy proteins in bone health

As our diets are expected to become significantly more plant-based in the future, the content of calcium is expected to be reduced, and our dietary protein sources will change. The supply of calcium in our diet is decisive for bone health, but inadequate protein supply can also affect bone growth and bone health. The aim of PROBONE is to investigate how inclusion of milk proteins in a plant-based diet, with an otherwise low content of protein and calcium, can facilitate bone mineralization and thereby improve bone health.

By: Anne Lau Heckmann

Adequate calcium intake and absorption are important to ensure bone mineralization during growth. Furthermore, research indicates that an adequate protein supply of the right composition is also crucial to ensure optimal bone growth. Here the type and origin of the protein seems to be relevant. 

The PROBONE project will test the hypothesis that milk contains proteins that are particularly beneficial for calcium bioavailability and bone mineralization. To test this, intervention studies will be conducted in rats who will be receiving a diet that exclusively contains plant protein, or two different diets where milk protein constitutes 50 % of the protein. Different proportions of casein and whey will also be tested in different treatment groups to investigate variations in effect of different dairy proteins. Subsequently, bone mineralization, bone structure and mechanical bone strength will be determined. To further elucidate mechanisms affecting calcium uptake in the gut and thereby impacting bone health, gut microbiome composition and metabolic activity will also be examined by using 16s rRNA gene amplicon sequencing and NMR-based metabolomics analyses, respectively. 

The study will contribute with important knowledge about the role of milk proteins in bone health, ensuring both high calcium bioavailability and the right amino acid profile to stimulate bone growth. Furthermore, it will also generate knowledge about how specific milk protein fractions may stimulate calcium absorption and bone growth. This knowledge will be useful for the dairy industry, as evidence-based knowledge about optimized calcium availability and stimulation of bone growth can be used in both product development and marketing.