Dietary protein and bone health: a systematic review and meta-analysis from the National Osteoporosis Foundation,

Abstract

Background: Considerable attention has recently focused on dietary protein's role in the mature skeleton, prompted partly by an interest in nonpharmacologic approaches to maintain skeletal health in adult life. Objective: The aim was to conduct a systematic review and metaanalysis evaluating the effects of dietary protein intake alone and with calcium with or without vitamin D (Ca6D) on bone health measures in adults. Design: Searches across 5 databases were conducted through October 2016 including randomized controlled trials (RCTs) and prospective cohort studies examining 1) the effects of "high versus low" protein intake or 2) dietary protein's synergistic effect with Ca6D intake on bone health outcomes. Two investigators independently conducted abstract and full-text screenings, data extractions, and risk of bias (ROB) assessments. Strength of evidence was rated by group consensus. Random-effects meta-analyses for outcomes with $4 RCTs were performed. Results: Sixteen RCTs and 20 prospective cohort studies were included in the systematic review. Overall ROB was medium. Moderate evidence suggested that higher protein intake may have a protective effect on lumbar spine (LS) bone mineral density (BMD) compared with lower protein intake (net percentage change: 0.52%; 95% CI: 0.06%, 0.97%, I2 : 0%; n = 5) but no effect on total hip (TH), femoral neck (FN), or total body BMD or bone biomarkers. Limited evidence did not support an effect of protein with Ca6D on LS BMD, TH BMD, or forearm fractures; there was insufficient evidence for FN BMD and overall fractures. Conclusions: Current evidence shows no adverse effects of higher protein intakes. Although there were positive trends on BMD at most bone sites, only the LS showed moderate evidence to support benefits of higher protein intake. Studies were heterogeneous, and confounding could not be excluded. High-quality, long-term studies are needed to clarify dietary protein's role in bone health. This trial was registered at www.crd.york.ac.uk as CRD42015017751.Am J Clin Nutr 2017;105:1528-43.

James Lind Alliance research priorities: what role do carbohydrates, fats and proteins have in the management of Type 2 diabetes, and are there risks and benefits associated with particular approaches?

“…Other studies have supported these findings but are confounded by marked carbohydrate restriction . Historically, health concerns regarding increasing the protein content of the diet have included accelerated decline in renal function and osteoporosis caused by excessive calcium loss. These concerns have not been substantiated in trials in individuals with Type 2 diabetes without renal disease .…”

Consumption of Greek yogurt during 12 weeks of high-impact loading exercise increases bone formation in young, adult males – a secondary analysis from a randomized trial

“…Nonetheless, the components of dairy, namely protein and calcium, have been extensively studied in relation to bone health. Metaanalyses indicate that higher protein (above the current recommended dietary allowance of 0.8 (g•kg -1 •d -1 )) and calcium intakes are associated with increased BMD and favourable changes in bone turnover markers across the lifespan (Darling et al 2009;Behringer et al 2014;Silk et al 2015;Tai et al 2015;Antoniak and Greig 2017;Shams-White et al 2017;Wallace and Frankenfeld 2017;Wu and Sun 2017). Only 1 meta-analysis in 2015 was conducted exclusively in healthy males (n = 867 from 6 studies, age range 16-84 years) and it determined that calcium supplementation (with and without vitamin D) improved BMD in this population (Silk et al 2015).…”

AGS and NIA Bench‐to Bedside Conference Summary: Osteoporosis and Soft Tissue (Muscle and Fat) Disorders

“…Protein supplementation in healthy adults also increases muscle strength and muscle mass or quality in healthy older adults and can improve functional recovery from illness . High dietary protein intakes have no adverse effects on bone health, and moderate evidence supports a protective effect on lumbar spine BMD . However, protein's effects on lean body mass and physical performance diminish with age .…”

“…1,36 High dietary protein intakes have no adverse effects on bone health, and moderate evidence supports a protective effect on lumbar spine BMD. 37 However, protein's effects on lean body mass and physical performance diminish with age. 38 The protein recommended daily allowance is based on nitrogen balance studies, an inadequate outcome for older adults at risk of sarcopenia.…”