Alcohol alters whole body composition, inhibits bone formation, and increases bone marrow adiposity in rats

Chronic alcohol abuse is a risk factor for osteoporosis and sarcopenia, but the long-term effects of alcohol on the immature musculoskeletal system are less clear. The present investigation in growing rats was designed to determine the effects of alcohol consumption on body composition, muscle mass, and bone mass, architecture, and turnover. Few studies have focused on the long-term effects of drinking on bone and muscle during skeletal maturation. Alcohol was included in the diet of 4-week-old male Sprague-Dawley rats (35% caloric intake) for 3 months. The controls were fed an isocaloric alcohol-free liquid diet ad libitum. A second study was performed in which the controls were pair-fed to the alcohol-fed animals. Compared to ad libitum-fed age-matched controls, alcohol-fed rats weighed less and had lower lean mass, fat mass, and percent body fat. In addition, they had lower slow- and fast-twitch muscle mass, lower total body bone mineral content and bone mineral density, and lower cancellous bone volume in the lumbar vertebra and proximal tibia. The effects of alcohol consumption on body composition were reduced when compared to the pair-fed control diet, indicating that caloric restriction was a comorbidity factor. In contrast, the effects of alcohol to decrease bone formation and serum leptin and IGF-I levels and to increase bone marrow adiposity appeared independent of caloric restriction. The skeletal abnormalities in growing alcohol-fed rats were due to a combination of effects specific to alcohol consumption and alcohol-induced caloric restriction.