This article is more than 5 years old. Information may no longer be current.
Calorie restriction did not lead to bone loss in young adults
But moderate calorie restriction did lead to changes in body composition.
Click Here to Manage Email Alerts
Moderate calorie restriction with preservation of calcium intake for six months led to changes in body composition without significant bone loss in young adults, according to the findings from a new trial.
“Our data do not support the notion that extreme weight loss (>10%) during short periods (three months) has a worse prognosis on bone health than gradual weight loss achieved during six months by moderate calorie restriction with or without exercise,” the authors wrote in a press release. “We speculate that in young individuals undergoing calorie restriction, minor adjustments in bone occur as a normal physiological adaptation to the reduced body mass.”
Researchers from Pennington Biomedical Research Center in Baton Rouge, La., conducted a trial to examine calorie restriction and its association with bone loss and fracture. Participants (n=46) were randomly assigned to one of four groups for six months:
- Group one: control group;
- Group two: 25% calorie restriction from baseline energy requirements;
- Group three: 25% energy deficit via combination of calorie restriction and increased aerobic exercise; and
- Group four: low calorie diet (890 kcal per day) followed by weight maintenance.
BMD unchanged for total body, hip
Mean body weight was reduced by –1% ± 1.1% in group one, by –10.4% ± 0.9% in group two, by –10% ± 0.8% in group three and by –13.9% ± 0.7% in group four, according to the researchers. No group showed any change in bone mineral density for total body or hip when compared with the control group.
Bone resorption increased by 23% ± 10% in group two, by 22% ± 9% in group three and by 74% ± 16% in group four compared with group one (4% ± 10%). Bone alkaline phosphatase levels were unchanged in all groups except for group two (–23% ± 10%).
“We conclude that longer studies with assessments of bone architecture are essential to future studies of calorie restriction to confirm that calorie restriction nutrient dense diets have no deleterious effect on bone health,” Leanne M. Redman, PhD, a clinical fellow instructor at Pennington Biomedical Research Center, told Endocrine Today. – by Christen Haigh
Arch Intern Med. 2008;168:1859-1866.
In addition to metabolic regulation to maintain mineral homeostasis, the skeleton also maintains homeostasis to maintain strain. As body mass declines, the loads imposed on the skeleton would also be expected to decline, but it remains an open question how large a change in loading would be sufficient to alter the point of homeostatic equilibrium. Increasing weight-bearing physical activity might be a sufficient intervention to counteract a decrease in body mass, were the weight change shown to be sufficient to provoke bone resorption. Thus, the questions addressed in this paper are important and worthy of study.
However, the study design is inadequate to answer them. Six months is too short a period to allow detection of a change in skeletal mass and the study was underpowered. That skeletal mass is in fact changing is suggested by the observation that resorption markers, but not formation markers, were increased in the weight loss groups. Moreover, their elevation at the end of the study suggests that adaptation of the skeleton to reduced body mass is a process that requires more than six months.
– Robert D. Blank, MD, PhD
Endocrine Today Editorial Board member