Protein quality affects bone status during moderate protein restriction in growing mice.
Adequate protein intake during development is critical to ensure optimal bone gain and to attain a higher peak bone mass later on. We hypothesized that the quality of the dietary protein is of prime importance for bone physiology during moderate protein restriction. The target population was growing Balb/C mice. We compared two protein restricted diets (6% of total energy as protein), one based on soy (LP-SOY) and one based on casein (LP-CAS). For comparison, a normal protein soy-based control group (NP-SOY) and a low protein group receiving an anabolic daily parathyroid hormone (PTH) 1-34 injection (LP-SOY+PTH) were included in the protocol. After 8weeks, LP-SOY mice had reduced body weights related to a lower lean mass whereas LP-CAS mice were not different from the NP-SOY group. LP-SOY mice were characterized by lower femoral cortical thickness, bone volume, trabecular number and thickness and increased medullar adiposity when compared to both the LP-CAS and NP-SOY groups. However, the dietary intervention had no effect on the vertebral parameters. The negative effect of the LP-SOY diet was correlated to an impaired bone formation as shown by the reduced P1NP serum level as well as the reduced osteoid surfaces and bone formation rate in the femur. PTH injection in LP-SOY mice had no effect on total weight or lean mass, but improved all bone parameters at both femoral and vertebral sites, suggesting that amino acid deficiency was not the primary reason for degraded bone status in mice consuming soy protein. In conclusion, our study showed that under the same protein restriction (6% of energy), a soy diet leads to impaired bone health whereas a casein diet has little effect when compared to a normal protein control.
UMR 914 INRA-AgroParisTech, Nutrition Physiology and Ingestive Behavior, 75005 Paris, France; Yoplait France, 92641 Boulogne-Billancourt, France. Electronic address: emilien.rouy@gmail.com.
Emilien
E
Rouy
INSERM U1059/LBTO, Université Jean Monnet, Université de Lyon, 42023 Saint-Étienne, France.
Laurence
L
Vico
INSERM U1059/LBTO, Université Jean Monnet, Université de Lyon, 42023 Saint-Étienne, France.
Norbert
N
Laroche
Yoplait France, 92641 Boulogne-Billancourt, France.
Valérie
V
Benoit
Yoplait France, 92641 Boulogne-Billancourt, France.
Brigitte
B
Rousseau
UMR 914 INRA-AgroParisTech, Nutrition Physiology and Ingestive Behavior, 75005 Paris, France.
François
F
Blachier
UMR 914 INRA-AgroParisTech, Nutrition Physiology and Ingestive Behavior, 75005 Paris, France.
Daniel
D
Tomé
UMR 914 INRA-AgroParisTech, Nutrition Physiology and Ingestive Behavior, 75005 Paris, France.
Anne
A
Blais
D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D001823:Body Composition / Q000187:drug effects; D015519:Bone Density / Q000187:drug effects; D001846:Bone Development / Q000187:drug effects*; D016723:Bone Remodeling / Q000187:drug effects; D001842:Bone and Bones / Q000033:anatomy & histology / Q000187:drug effects*; D002364:Caseins / Q000494:pharmacology*; D018753:Diet, Protein-Restricted; D051379:Mice; D008807:Mice, Inbred BALB C; D009929:Organ Size / Q000187:drug effects; D010012:Osteogenesis / Q000187:drug effects; D030262:Soybean Proteins / Q000494:pharmacology*
D015415:Biomarkers; D002364:Caseins; D030262:Soybean Proteins
Bone architecture; Bone turnover; Parathyroid hormone; Protein quality; Protein undernutrition