Changes in bone density and bone quality caused by single fasting for 96 hours in rats

Area of Science:

• Biomedical Science
• Bone Biology
• Nutritional Science

Background:

• Dietary restrictions and fasting are common weight-loss practices among young women.
• Osteoporosis is a growing public health concern, particularly in industrialized nations.
• Understanding the impact of fasting on bone quality is crucial.

Purpose of the Study:

• To investigate the effects of short-term fasting on bone quality and fragility.
• To assess bone architecture and mechanical properties following a fasting and refeeding period.

Main Methods:

• Male Wistar rats were divided into control and fasting groups.
• The fasting group underwent 4 days of fasting followed by 10 days of ad libitum feeding.
• Bone quality was evaluated using contrast-enhanced micro-CT imaging of the lumbar spine, focusing on bone architecture and mechanical parameters like minimum cross-sectional moment and polar moment.

Main Results:

• Fasting (96 hours) significantly decreased bone density and reduced strength against bending (minimum cross-sectional moment) and torsion (polar moment).
• Bone mineral content rapidly recovered after refeeding, showing no difference from controls by day 4.
• However, the reduced minimum cross-sectional moment and polar moment did not recover and worsened over the refeeding period.

Conclusions:

• Fasting can negatively impact bone quality, specifically reducing bone's resistance to bending and torsion.
• These bone strength parameters (minimum cross-sectional moment and polar moment) are sensitive indicators of fasting-induced bone changes.
• These findings highlight the potential long-term skeletal risks associated with fasting, even after nutritional recovery.