Associations of Total, Dairy, and Meat Protein with Markers for Bone Turnover in Healthy, Prepubertal Boys

Abstract

We previously reported that high intake of milk, but not meat, equal in protein content, increased serum insulin-like growth factor-I (sIGF-I) in prepubertal boys. sIGF-I plays a key role in bone metabolism. Therefore, the aim of this cross-sectional study was to investigate associations of total, dairy, and meat protein intake with markers for bone turnover and sIGF-I in prepubertal, healthy boys (n = 81). We measured bone turnover (enzyme-linked immunoassay) in serum osteocalcin (sOC), bone-specific alkaline phosphatase (sBAP), and C-terminal telopeptide of collagen type-I (sCTX); dietary intake was estimated from a 3-d weighed food record. sIGF-I and its binding protein-3 were assessed (immunoassay) in a subgroup of 56 boys. All statistical models included effects of age, BMI, and energy intake. Dairy protein was negatively associated with sOC (P = 0.05) but not significantly associated with sBAP and sCTX. Further analyses showed that dairy protein decreased (P = 0.05) sOC at a high meat protein intake (>0.8 g/kg), whereas meat protein increased (P = 0.03) sOC at a low dairy protein intake (<0.4 g/kg). Total and meat protein intake was positively associated with sBAP (P < or = 0.04) but not significantly associated with sOC and sCTX. Free sIGF-I was positively associated with total (P < 0.01) and dairy (P = 0.06) protein but not with meat protein. Our results indicate that dairy and meat protein may exhibit a distinct regulatory effect on different markers for bone turnover. Future studies should focus on differential effects of dairy and meat protein on bone health during growth.

Developmental stage‐dependent influence of environmental factors on growth of rural Sundanese children in West Java, Indonesia

“…This study highlighted that a significant correlation between IGF-IZ and energy or protein intake was found only in 9 to 11-year-old males for energy intake and in 7 to 9-year-old females for energy and protein intakes immediately before their adolescence or the onset of puberty. There were two major differences between this study and previous studies that have targeted healthy children (Hoppe et al, 2004;Budek et al, 2007;Kerver et al, 2010). First, previous studies reported the relevance of animal protein intake to IGF-I level; in contrast, this study found the relevance of protein and energy intakes.…”

“…Malnutrition and a high burden of infectious diseases are involved in delaying the onset of puberty, although elucidation of the underlying physiological mechanisms through which this delay occurs has remained elusive (McDade, 2003). The determining role of nutrient intake in IGF-I level has been recognized not only among malnourished children (Nazaimoon et al, 1996;Mart ınez de Icaya et al, 2000) and children with anorexia nervosa (Misra et al, 2004) but also among healthy children (Hoppe et al, 2004;Budek et al, 2007;Kerver et al, 2010). Therefore, it is possible that the correlation between nutritional status and nutrient intake is mediated by IGF-I.…”

“…The second and more important finding concerned the timing of these effects. Hoppe et al (2004) and Budek et al (2007) targeted children in childhood or in the prepuberty stage, and Kerver et al (2010) targeted females HAZ and WAZ were independent variables, and each child's sex, age, intestinal helminthiasis, anemia, NARs for energy and protein, and IGF-IZ and IGFBP-3Z scores were dependent variables, and they were entered into the multiple regression models. Among the dependent variables, only variables with significant contributions were detected.…”

Amount and type of protein influences bone health

“…Some, but not all (22), studies have found that meat as a protein source is associated with higher serum levels of IGF-1 (20,21), which is in turn associated with increased bone mineralization and fewer fractures (23). Soy foods have been linked with lower levels of IGF-1 (21).…”

Review of Ca Metabolic Studies and a Model for Optimizing Gastrointestinal Ca Absorption and Peak Bone Mass in Adolescents

“…Dietary protein also increases IGF-I levels during growth, as milk supplementation increased serum IGF-I levels in adolescent girls (Cadogan et al, 1997). Serum IGF-I was positively associated with dietary protein in 8-year-old boys (Budek et al, 2007). Historically, dietary protein was thought to have a negative effect on Ca balance and bone mass.…”