Monosodium Glutamate Supplementation Improves Bone Status in Mice Under Moderate Protein Restriction

Abstract

Adequate protein intake during development is critical to ensure optimal bone gain and to attain a higher peak bone mass later. Using a mild protein restriction model in Balb/C mice consuming 6% of their total energy intake as soy protein (LP‐SOY)—for which we observed a significantly lower femoral cortical thickness, bone volume, trabecular number, and thickness reduction—we evaluated the effects of monosodium glutamate (MSG) supplementation at different concentrations (0.5, 1, 5, 10, and 20 g/kg of diet) on bone characteristics in LP‐SOY‐fed mice. After 6 and 12 weeks, LP‐SOY‐fed mice had lower BMD and reduced body weight related to lower lean mass, which was associated with a reduced IGF‐1 level. The negative effect of the LP‐SOY diet on BMD correlated with impaired bone formation. MSG supplementation, at 5, 10, and 20 g/kg of diet, and PTH injection, used as a positive control, were able to improve BMD and to increase osteoblast activity markers (P1NP and osteocalcin), as well as glutamine plasma concentration. An analysis of bone microarchitecture found that cortical bone was less sensitive to protein restriction than trabecular bone, and that MSG ingestion was able to preserve bone quality through an increase of collagen synthesis, although it did not allow normal bone growth. Our study reinforces the view that glutamate can act as a functional amino acid for bone physiology and support clinical investigation of glutamate supplementation in adults characterized by poor bone status, notably as a result of insufficient protein intake. © 2019 The Authors. JBMR Plus published by Wiley Periodicals, Inc. on behalf of American Society for Bone and Mineral Research.

Bovine lactoferrin is efficient for improving bone characteristics: a study based on a new preclinical model of marked bone fragility

“…Thus, our data are in good accordance with the results of previous studies showing that a decrease in estrogen level is associated with central obesity, insulin resistance, and decreased energy expenditure ( [29][30]). As shown in previous experiments [11][12], LP diet reduced IGF-1 level. Our data show that bLF supplementation was able to increase several endocrine and physiological parameters, namely IGF-1 level, muscle mass, and muscle strength, thus once again supporting that bLF can increase protein synthesis in target tissues [31].…”

“…Therefore, osteoporosis is a major public health concern. We have previously shown in a model with mice fed a low protein diet (6% of total energy by soy protein) that this dietary condition reduces body weight associated with lower lean mass and BMD compared with mice receiving an adequate protein supply [11][12].…”

“…Protein intakes lower than estimated protein requirements are often observed in specific groups of individuals, particularly in elderly patients with osteoporosis. In preclinical studies, the utilization of dietary supplements in the form of specific proteins such as lactoferrin or individual amino acids has been shown to improve osteoblast activity and bone status in the situation of short supply of dietary proteins [12]. Lactoferrin (LF) is known to possess various biological properties, including anti-inflammatory and immunomodulatory effects [13].…”

Performance and Physiological Response of Chickens Supplemented with Dietary L-Glutamic Acid During the Late Phase of Egg Production

“…Brakspear and Mason (2012) mentioned that Glu plays a role in bone formation and mass maintenance. Also, Blais et al (2019) found that increase in Gln plasma concentration stimulates osteoblast activity.…”