A methionine-restricted diet and endurance exercise decrease bone mass and extrinsic strength but increase intrinsic...

Area of Science:

• Bone Biology
• Nutritional Science
• Exercise Physiology

Background:

• Dietary methionine restriction (MR) is proposed to offer health benefits comparable to endurance exercise.
• Investigating the combined effects of MR and exercise on growing bone is crucial for understanding skeletal adaptations.

Purpose of the Study:

• To examine the impact of varying dietary methionine levels and endurance exercise on bone health in growing rats.
• To compare the effects of methionine restriction and exercise on bone mass, density, strength, and biomechanical properties.

Main Methods:

• Male Sprague-Dawley rats (7 weeks old) were assigned to diets with different l-methionine concentrations (0.86%, 0.52%, 0.17%) with or without endurance exercise for 8 weeks.
• Evaluated body weight, serum bone biomarkers (osteocalcin, C-terminal telopeptide of type 1 collagen), bone mineral content (BMC), bone mineral density (BMD), and femoral biomechanical properties.

Main Results:

• Both methionine restriction (0.17% Met) and endurance exercise significantly reduced body weight and whole bone mass (BMC, BMD).
• Methionine restriction and exercise decreased bone mineralization activity and trabecular osteoclast density.
• Femora from restricted and exercised rats showed reduced size and extrinsic strength but enhanced intrinsic biomechanical properties.

Conclusions:

• Dietary methionine restriction and endurance exercise lead to decreased overall bone mass and size in growing rats.
• Despite reduced mass, these interventions may improve intrinsic bone strength, indicating a nuanced effect on skeletal integrity.
• Further research is needed to elucidate the long-term skeletal implications of these interventions.