Aims Whey protein may improve bone turnover and have anti-osteoporotic effects. The aim of the present randomised, controlled, crossover trial was to evaluate the effects of a whey protein pre-meal on bone turnover in people with type 2 diabetes and controls.

Methods Two groups, matched on sex, age and body mass index, comprising 12 participants with and 12 participants without type 2 diabetes were randomly given a pre-meal of whey protein (20 g) or water, which was consumed 15 min before a fat-rich meal or a fat-rich meal supplemented with 20 g whey protein. During a 360-min period, postprandial responses in bone turnover were examined.

Results Osteocalcin, P-procollagen type 1 amino terminal propeptide (P1NP), C-terminal cross-linked telopeptide of type-I collagen (CTX) and parathyroid hormone (PTH) were lower at baseline and PTH, osteocalcin and P1NP were lower during the entire postprandial phase in participants with type 2 diabetes than in participants without type 2 diabetes. We observed similar postprandial responses in bone turnover markers between persons with and without type 2 diabetes. We observed no effect of the whey protein or the water pre-meal on bone turnover markers. The changes were unrelated to secretion of hormones of the gut-bone axis.

Conclusion Osteocalcin, P1NP, CTX and PTH all decreased following meal ingestion. We observed no convincing effect of a whey protein pre-meal on bone turnover. However, these results confirm that people with type 2 diabetes have low bone turnover and that the decreased bone formation markers are also extend into the postprandial responses.