Exercise and Protein Effects on Strength and Function with Weight Loss in Older Women.

Obesity negatively affects lower extremity physical function (LEPF) in older adults. Exercise and a higher protein diet are both known to positively and independently affect body composition, muscle strength, and LEPF during weight loss; however, their potential interactive effects have not been well characterized in older women. PURPOSE: The aim of this study was to determine the relative efficacy of a higher protein diet with or without exercise to improve body composition, muscle strength, and LEPF in older inactive overweight/obese women after weight loss. METHODS: Postmenopausal women (body mass index = 31.1 ± 5.1 kg·m, 69.2 ± 3.6 yr) completed a 6-month weight loss program after randomization to three groups (n = 72 randomized; 15% dropout): 1) higher protein diet (PRO, ~30% energy from protein; n = 20), 2) PRO plus exercise (PRO + EX; n = 19), or 3) a conventional protein control diet plus EX (CON + EX, ~18% energy from protein; n = 22). EX was supervised, multicomponent (aerobic, muscle strengthening, balance, and flexibility), and three sessions per week. Body composition was measured via dual-energy x-ray absorptiometry, leg strength by isokinetic dynamometry, and LEPF via 6-min walk, 8-ft up and go, and 30-s chair stand tests. RESULTS: Changes in weight (-7.5 ± 4.1 kg; -9.2% ± 4.8%), fat mass, and leg lean mass did not differ among groups (all P > 0.50). Despite weight loss, muscle strength improved in the exercise groups (PRO + EX and CON + EX) but it declined in the PRO group (P = 0.008). For all LEPF measures, the PRO group had attenuated improvements compared with both PRO + EX and CON + EX (all P < 0.01). CONCLUSION: Exercise during weight loss is critical to preserve strength and enhance LEPF; however, a higher protein diet does not appear to influence body composition, muscle strength, or LEPF changes when combined with multicomponent exercise.

The bivalent ligand, MMG22, reduces neuropathic pain after nerve injury without the side effects of traditional opioids.

ABSTRACT: Functional interactions between the mu opioid receptor (MOR) and the metabotropic glutamate receptor 5 (mGluR5) in pain and analgesia have been well established. MMG22 is a bivalent ligand containing MOR agonist (oxymorphamine) and mGluR5 antagonist (MPEP) pharmacophores tethered by a 22-atom linker. MMG22 has been shown to produce potent analgesia in several models of chronic inflammatory and neuropathic pain (NP). This study assessed the efficacy of systemic administration of MMG22 at reducing pain behavior in the spared nerve injury (SNI) model of NP in mice, as well as its side-effect profile and abuse potential. MMG22 reduced mechanical hyperalgesia and spontaneous ongoing pain after SNI, with greater potency early (10 days) as compared to late (30 days) after injury. Systemic administration of MMG22 did not induce place preference in naive animals, suggesting absence of abuse liability when compared to traditional opioids. MMG22 also lacked the central locomotor, respiratory, and anxiolytic side effects of its monomeric pharmacophores. Evaluation of mRNA expression showed the transcripts for both receptors were colocalized in cells in the dorsal horn of the lumbar spinal cord and dorsal root ganglia. Thus, MMG22 reduces hyperalgesia after injury in the SNI model of NP without the typical centrally mediated side effects associated with traditional opioids.

Reduced body weight or increased muscle quality: Which is more important for improving physical function following exercise and weight loss in overweight and obese older women?

The purpose of this study was to examine the relative contributions of changes in muscle quality and body composition to changes in lower-extremity physical function (LEPF) following a 6-month exercise and weight loss intervention in overweight and obese older women. Thirty-eight overweight and obese (BMI = 30.0 ±â€¯4.4 kg/m2) older (age = 69.3 ±â€¯4.1 y) women completed 6 months of multicomponent exercise (cardiorespiratory, resistance, balance and flexibility training) and weight loss (hypocaloric diet that reduced energy intake by ~500 kcal/d). Body composition was measured via dual-energy X-ray absorptiometry and muscle quality (N-m/kg) was defined as maximal concentric isokinetic knee torque divided by upper-leg lean mass. The standardized scores of four objective measures of physical function were summed to yield a composite LEPF Z-score. At 6 months, there were significant reductions in body weight (-9.6 ±â€¯3.5%, p < 0.01), absolute fat mass (-6.8 ±â€¯2.4 kg, p < 0.01) and relative adiposity (-4.9 ±â€¯2.1%, p < 0.01). There were also improvements in both muscle quality (+1.6 ±â€¯1.8 N-m/kg, p < 0.01) and individual measures of LEPF (11-57%, p < 0.01). Multivariate linear regression indicated that increased muscle quality was the strongest independent predictor of an improvement in LEPF Z-score (standardized ß = 0.64, p < 0.01) and explained 34% of the variance. A reduction in body weight also predicted an improvement in LEPF, independent of the change in muscle quality. In conclusion, muscle quality can be increased in the presence of clinically meaningful weight loss, and is the primary determinant of improved physical function in overweight/obese older women.

Flexible Eating Behavior Predicts Greater Weight Loss Following a Diet and Exercise Intervention in Older Women.

Eating behaviors (cognitive restraint, flexible and rigid restraint, disinhibition, hunger) have been associated with obesity and weight loss success in middle-aged individuals, but little is known about these relationships in older adults. This study examined relationships between eating behaviors and weight loss in overweight/obese older women (n = 61; 69 ± 3.6 years; body mass index = 31.1 ± 5.0 kg/m2) completed a 6-month behavioral weight loss intervention. Baseline, postintervention, and change measures of eating behaviors (51-items Three-Factor Eating Questionnaire) were assessed for relationships with weight loss. In the final regression model, an increase in flexible restraint accompanied by a decrease in rigid restraint predicted greater weight loss (adjusted R2 = 0.21, Model F (4, 56) = 4.97, P < 0.01). No associations were found with disinhibition or hunger and degree of weight loss (all P > 0.05). Results suggest encouraging a flexible approach to eating behavior and discouraging rigid adherence to a diet may lead to better intentional weight loss for overweight and obese older women.