Dietary protein supplementation increases peak bone mass acquisition in energy-restricted growing rats.
Peak bone mass is a major determinant of osteoporosis pathogenesis during aging. Respective influences of energy and protein supplies on skeletal growth remains unclear. We investigated the effect of a 5-mo dietary restriction on bone status in young rats randomized into six groups (n = 10 per group). Control animals were fed a diet containing a normal (13%) (C-NP) or a high-protein content (26%) (C-HP). The other groups received a 40% protein energy-restricted diet (PER-NP and PER-HP) or a 40% energy-restricted diet (ER-NP and ER-HP). High-protein intake did not modulate bone acquisition, although a metabolic acidosis was induced and calcium retention impaired. PER and ER diets were associated with a decrease in femoral bone mineral density. The compensation for protein intake in energy-restricted conditions induced a bone sparing effect. Plasma osteocalcin (OC) and urinary deoxypyridinoline (DPD) assays revealed a decreased OC/DPD ratio in restricted rats compared with C animals, which was far more reduced in PER than in ER groups. Circulating IGF-1 levels were lowered by dietary restrictions. In conclusion, both energy and protein deficiencies may contribute to impairment in peak bone mass acquisition, which may affect skeleton strength and potentially render individuals more susceptible to osteoporosis.
Mardon
Julie
J
Unité de Nutrition Humaine UMR1019, INRA Clermont-Ferrand/Theix, Saint Genès Champanelle, France. mardon@enitac.fr
Trzeciakiewicz
Anna
A
Habauzit
Véronique
V
Davicco
Marie-Jeanne
MJ
Lebecque
Patrice
P
Mercier
Sylvie
S
Tressol
Jean-Claude
JC
Horcajada
Marie-Noëlle
MN
Demigné
Christian
C
Coxam
Véronique
V
D000596:Amino Acids / Q000652:urine; D000821:Animal Feed; D000818:Animals; D001696:Biomechanical Phenomena; D015519:Bone Density; D001842:Bone and Bones / Q000473:pathology*; D019587:Dietary Supplements; D005269:Femur / Q000033:anatomy & histology; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D007477:Ions; D008297:Male; D015675:Osteocalcin / Q000097:blood; D010024:Osteoporosis / Q000473:pathology; D051381:Rats; D017208:Rats, Wistar
D000596:Amino Acids; D007477:Ions; D015675:Osteocalcin; D007334:Insulin-Like Growth Factor I; C036020:deoxypyridinoline