Does perioperative nutrition and oral carbohydrate load sustainably preserve muscle mass after bariatric surgery? A randomized control trial.

BACKGROUND: Perioperative nutrition and preoperative oral carbohydrate loading (CHL) have a beneficial impact on the outcomes of gastrointestinal oncological surgery. However no data exists on their effect on morbidly obese patients. OBJECTIVES: Our aim was to establish the short-term and long-term impact of these modalities, notably on metabolically active lean body mass (LBM) - an important factor in maintaining long-term weight loss. METHODS: Patients undergoing laparoscopic Roux-en-Y gastric bypass were randomized to standard management or intervention: CHL drinks consumed 12 and 2 hours presurgery, and immediate postoperative peripheral parenteral nutrition. The primary outcome measured was LBM, measured by Bioelectrical Impedance Analysis (BIA), one and 12 months postsurgery. Secondary outcomes included excess weight loss (EBWL), 30-day complication rate, and length of stay. RESULTS: Of the 203 randomized patients, 198 were included in the analysis. All 101 patients in the control group completed the one-year follow up and 76 completed the BIA. In the intervention group, 93 of 97 patients completed the one-year follow-up and 71 completed the BIA. At one and 12 months follow-up, body composition, LBM, or EBWL were comparable. There was no difference in operative outcomes, complications rates, or length of stay. There was no adverse effect in the intervention group. CONCLUSIONS: In a highly homogeneous group of morbidly obese patients with one-year follow-up, CHL and short-term parenteral nutrition did not lead to significant or sustained LBM preservation or modification in EBWL. There was no significant decrease in complications or length of stay. Our study confirms the safety of these interventions, even in previously unstudied Type 2 diabetic patients.

Age-related differences in fat-free mass, skeletal muscle, body cell mass and fat mass between 18 and 94 years.

OBJECTIVE: To determine (1) lean and fat body compartments, reflected by fat-free mass (FFM), appendicular skeletal muscle mass (ASMM), body cell mass (BCM), total body potassium (TBK), fat mass and percentage fat mass, and their differences between age groups in healthy, physically active subjects from 18 to 94 y of age; and (2) if the rate of decrease in any one of the parameters by age might be accelerated compared to others. METHODS: A total of 433 healthy ambulatory Caucasians (253 men and 180 women) aged 18--94 y were measured by dual-energy X-ray absorptiometry (DXA) and whole body scintillation counter (TBK counter) using a large sodium iodide crystal (203 mm diameter). RESULTS: The ASMM change (-16.4 and -12.3% in men and women, respectively) in >75 y-old compared to 18 to 34-y-old subjects was greater than the FFM change (-11.8 and -9.7% in men and women, respectively) and this suggests that skeletal muscle mass decrease in older subjects was proportionally greater than non-skeletal muscle mass. BCM (-25.1 and -23.2% in men and women, respectively) and TBK differences were greater than the differences in FFM or ASMM suggesting altered composition of FFM in older subjects. Women had lower peak FFM, ASMM, BCM and TBK than men. CONCLUSIONS: The decline in FFM, ASMM, BCM and TBK is accelerated in men and women after 60 y of age and FFM, ASMM, BCM and TBK are significantly lower than in younger subjects. Fat mass continued to increase until around 75 y.

Single prediction equation for bioelectrical impedance analysis in adults aged 20--94 years.

Existing equations for bioelectrical impedance analysis (BIA) are of limited use when subjects age or become overweight because these equations were developed in young, normal-weight subjects and are not valid in elderly or overweight people. The purpose of this study was to validate a single BIA equation in healthy white subjects aged 22--94 y with a body mass index between 17.0 and 33.8 kg/m(2). Healthy subjects (202 men and 141 women) aged 20--94 y were measured by two methods: fat-free mass (FFM) was measured by dual-energy x-ray absorptiometry (Hologic QDR-4500) and by a bioelectrical impedance analyzer (Xitron 4000B). Validity of BIA was assessed by double cross validation. Because correlations were high (r = 0.986--0.987) and prediction errors low, a single equation was developed using all subjects, as follows: FFM = -4.104 + (0.518 x height(2)/resistance) + (0.231 x weight) + (0.130 x reactance) + (4.229 x sex: men = 1, women = 0). FFM predicted with dual-energy x-ray absorptiometry was 54.0 +/- 10.7 kg. BIA-predicted FFM was 54.0 +/- 10.5 kg (r = 0.986, standard error of the estimate = 1.72 kg, technical error = 1.74 kg). In conclusion, the new Geneva BIA equation was valid for prediction of FFM in healthy adults aged 22--94 y with body mass indexes between 17.0 and 33.8 kg/m(2). Inclusion of reactance in the single prediction equation appeared to be essential for use of BIA equations in populations with large variations in age or body mass.