Eating restraint is negatively associated with biomarkers of bone turnover but not measurements of bone mineral density in young women.

Relationships among bone mineral density (BMD), bone turnover markers, cortisol, calcium and vitamin D intakes, and cognitive eating restraint score were examined. Sixty-five healthy women, ages 18 to 25 years, had total body, spine, hip, and forearm BMD measured by dual-energy x-ray absorptiometry. Serum osteocalcin, urinary cross-linked N-telopeptide of type I collagen (NTx), and salivary cortisol were measured, and intakes of calcium and vitamin D were estimated from questionnaires. Cognitive eating restraint scores were determined from the Eating Inventory. Associations between measures were analyzed by Pearson correlations; predictors of BMD and bone turnover markers were tested using stepwise regression. Serum osteocalcin (P<0.01) and urinary NTx (P<0.05) were negatively related to cognitive eating restraint score. Intakes of calcium (P<0.05) and vitamin D (P<0.05) were associated with forearm BMD. Regression analyses indicated that vitamin D intake predicted total body (P<0.08) and forearm (P<0.01) BMD. Negative associations between cognitive eating restraint score and bone biomarkers suggest a reduction in bone remodeling, not reflected in current BMD.

Effect of post-exercise supplement consumption on adaptations to resistance training.

OBJECTIVE: Athletes are interested in nutritional manipulations that may enhance lean tissue gains stimulated by resistance training. Some research demonstrates that acute consumption of food containing protein causes superior muscle protein synthesis compared to isoenergetic foods without protein. This benefit has not been verified in longer-term training studies. We compared body composition and muscle function responses to resistance training in males who consumed a carbohydrate or a multi-macronutrient beverage following each training session. METHODS: Nineteen, untrained men (18-25 years) consumed either a milk (MILK) or a carbohydrate-electrolyte (CHO) drink immediately following each workout during a 10 week resistance training program. Muscle strength (1RM for seven exercises), body composition (DXA scan), fasted, resting concentrations of serum total and free testosterone, cortisol, IGF-1, and resting energy expenditure (REE) were measured prior to and at the end of training. RESULTS: Resistance training caused an increase (44 +/- 4%, p < 0.001) in muscular strength for all subjects. The training program reduced percent body fat (8%, p < 0.05, -0.9 +/- 0.5 kg) and increased fat-free soft tissue (FFST) mass (2%, 1.2 +/- 0.3 kg, p < 0.01). MILK tended to increase body weight and FFST mass (p = 0.10 and p = 0.13, respectively) compared to CHO. Resting total and free testosterone concentrations decreased from baseline values in all subjects (16.7%, 11%, respectively, p < 0.05). Significant changes in fasting IGF-1, cortisol, and REE across training were not observed for either group. CONCLUSION: Post-resistance exercise consumption of MILK and CHO caused similar adaptations to resistance training. It is possible that a more prolonged training with supplementation period would expand the trend for greater FFST gains in MILK.

Bone mineral density in postmenopausal women: does exercise training make a difference?

Although postmenopausal women are encouraged to exercise to preserve bone mineral density (BMD), few studies have looked at what type of exercise is most effective.