B-41 Free Communication/Poster - Physical Activity Interventions in Youth Wednesday, May 28, 2014, 1:00 PM - 6:00 PM Room: WB1
Low-intensity physical activity (LIPA) reduces postprandial glucose and insulin concentrations in adults, but it is unknown if LIPA improves postprandial glucose and insulin concentrations in obese adolescents consuming high-fructose (HF) or high-glucose (HG) diets.
PURPOSE: To determine if LIPA would improve postprandial glucose and insulin concentrations in obese adolescents consuming HF and HG diets.
METHODS: Seven obese male and female adolescents (18 ± 1 yr, 97th BMI percentile) performed four, 15 d trials in random order including 1) HF diet (50 g fructose/d added to normal diet) with only normal activities of daily living (7,548 ± 285 steps/d), 2) HG diet (50 g glucose/d) with only normal activities of daily living (7,915 ± 680 steps/d), 3) HF diet with LIPA added (13,730 ± 796 steps/d), and 4) HG diet with LIPA added (12,918 ± 721 steps/d). On the 15th d of each trial, the participants reported to the lab for mixed meal testing in which they consumed three liquid shakes (one shake every 4 h, either HF or HG, each shake 450 Calories, 45% Carbohydrate [16.7 g fructose or 20.1 g glucose], 40% fat, 15% protein), over a 12 h period with frequent blood samples taken throughout each trial and assayed for glucose, insulin, and c-peptide concentrations. During the HF and HG trials, the participants took < 2,000 steps while in the lab. During the HF + LIPA and HG + LIPA trials, the participants performed treadmill walking at a self-selected pace (walked for 5 min every h and for 1 h straight prior to the last shake) so that they took > 13,000 steps during testing. Insulin secretion rates (ISR) were calculated using the ISEC deconvolution program and hepatic insulin clearance was calculated as the molar ratio of insulin to c-peptide.
RESULTS: Postprandial glucose, ISR, or insulin clearance was not different between HF and HG diets. LIPA did not alter postprandial glucose concentrations or insulin clearance (P > 0.05). However, the ISR was 52% and 34% greater during the HF and HG sedentary trials, respectively, compared to the HF + LIPA and HG + LIPA trials (P < 0.05).
CONCLUSIONS: Replacing some sitting time with walking at a low intensity reduces postprandial insulin secretion while consuming a HF and HG diet. Independent of diet, LIPA is potentially an important clinical strategy for reducing an adolescent’s risk of developing diabetes.