Interactive effects of milk basic protein supplements and habitual physical activity on bone health in older women: A 1-year randomized controlled trial

A 1-year randomized controlled trial examined effects of milk basic protein (MBP) supplementation (40 mg day−1) and daily physical activity (step count and duration of exercise > 3 metabolic equivalents [METs]) on bone metabolism, forearm bone mineral density (BMD) and a calcaneal osteosonic index (OSI) in 79 females aged 65–86 years. MBP did not affect osteocalcin or bone-specific alkaline phosphatase, but at 12 months, excretion of deoxypyridinoline and cross-linked N-teleopeptides of type I collagen (NTx) were significantly less than in controls. Experimental subjects also maintained BMD and had a 1.5% increase of OSI at 12 months. After adjustments for age and baseline bone parameters, osteocalcin, deoxypyridinoline, NTx and/or OSI at 12 months were significantly related to step count and/or duration of activity > 3 METs. MBP reduced markers of bone loss, particularly in the lower extremities. Reduced resorption of bone was also associated with moderate-intensity/duration exercise, MBP therapy interacting significantly with habitual physical activity.