Effects of exercise-induced weight loss on acylated and unacylated ghrelin in overweight children
Controversial data on ghrelin concentration during exercise in human subjects have been published. We tested the hypothesis that exercise could affect acylated ghrelin (AG) and unacylated ghrelin (UAG), which could partly explain the previously reported inconsistent findings on the association of exercise with changes in ghrelin. A prospective randomized study. We randomized 17 overweight volunteers (11-year-old boys) to a 12-week combined exercise group (EG, n = 8) or control group (CG, n = 9). At baseline, 1, 4 and 12 weeks, we measured body weight and composition, insulin, leptin, total ghrelin and acylated ghrelin. Compared with the CG, body weight, percentage body fat and homeostatic model assessment (HOMA) indices were significantly lower throughout the 12 weeks in the EG. Total ghrelin and UAG levels gradually increased to 131.9 +/- 5.2% and 130.4 +/- 5.2% of baseline, respectively, at week 12 in the EG, whereas AG concentration remained unchanged throughout the 12 weeks both within each group and between the groups. At week 12, there were differences in the total ghrelin level and UAG level between the groups. This study shows an increase in unacylated acylated ghrelin and unchanged acylated ghrelin after a 12-week combined exercise programme in overweight children. These findings provide evidence of favourable effects of exercise on improving energy metabolism.
[Show abstract] [Hide abstract] ABSTRACT: Objective. Determine the effects of exercise on body mass index (BMI in kg·m−2) among overweight and obese children and adolescents. Methods. Trial sequential meta-analysis of randomized controlled exercise intervention trials ≥ 4 weeks and published up to November 11, 2014. Results. Of the 5,436 citations screened, 20 studies representing 971 boys and girls were included. Average length, frequency, and duration of training were 13 weeks, 3 times per week, for 46 minutes per session. Overall, random-effects models showed that exercise decreased BMI by 3.6% (mean: −1.08; 95% CI: −0.52 to −1.64; Q = 231.4; p < 0.001; I2 = 90.9%; 95% CI: 87.6% to 93.4%; D2 = 91.5%). Trial sequential meta-analysis showed that changes in BMI crossed the monitoring boundary for a type 1 error in 2010, remaining stable thereafter. The number needed to treat was 5 while the percentile improvement was 26.9. It was estimated that approximately 2.5 million overweight and obese children in the US and 22.0 million overweight and obese children worldwide could reduce their BMI by participating in a regular exercise program. Overall quality of evidence was rated as moderate. Conclusions. Exercise is associated with improvements in BMI among overweight and obese children and adolescents. This trial is registered with PROSPERO Trial Registration #CRD42015017586.0Comments 1Citation
- "95% CI = 0 to 62.5; í µí°· 2 = 21.1%). With the same study deleted , reductions in percent body fat remained statistically significant along with statistically significant heterogeneity, moderate inconsistency, and large diversity (í µí±: 81.9; í µí°· 2 = 75.7%). Increases in VO 2max in mL⋅kg −1 ⋅min −1 also remained statistically significant along with statistically significant heterogeneity, moderate inconsistency, and large diversity when one outlier  No outliers were identified for changes in lower and upper body muscular strength. "
[Show abstract] [Hide abstract] ABSTRACT: Obesity, a disorder of body composition, is defined by a relative or absolute excess of body fat. In general adult population, obesity has been associated with a diverse array of adverse health outcomes, including major causes of death such as cancer, diabetes, cardiovascular disease, as well as functional impairment from problems such as osteoarthritis and sleep apnea. Ghrelin is a newly discovered peptide hormone which plays an important role in obesity. It is a powerful, endogenous orexigenic peptide and has a crucial function in appetite regulation, as well as short – and long-term energy homeostasis. In the presence of increased obesity, decreased physical activity, and high food consumption, the relationship between exercise, appetite, food intake and ghrelin levels has important implications. In this review, we discuss the effect of acute and chronic exercise performance on appetite, food intake and ghrelin and their relationships.0Comments 0Citations
- "Previous research reported that des-acyl ghrelin decreased food intake and stimulated negative energy balance by delaying gastric discharge . Kim et al.  reported that body weight, BMI, and body fat percentage decreased in obese children after 12-week resistance and aerobic exercise, while total ghrelin increased at 30.4%, des-acyl ghrelin increased at 31.9%, and acyl ghrelin did not change. There is a strong correlation between decrease in body weight and body fat and the increase in des-acyl after exercise in obese chil- dren . "
[Show abstract] [Hide abstract] ABSTRACT: The purpose of this study was to investigate the effects of 12 weeks of exercise training on gut hormone levels after a single bout of exercise in middle-aged Japanese women. Twenty healthy middle-aged women were recruited for this study. Several measurements were performed pre and post exercise training, including: body weight and composition, peak oxygen consumption (peak VO2), energy intake after the single bout of exercise, and the release of gut hormones with fasting and after the single bout of exercise. Exercise training resulted in significant increases in acylated ghrelin fasting levels (from 126.6 ± 5.6 to 135.9 ± 5.4 pmol/l, P < 0.01), with no significant changes in GLP-1 (from 0.54 ± 0.04 to 0.55 ± 0.03 pmol/ml) and PYY (from 1.20 ± 0.07 to 1.23 ± 0.06 pmol/ml) fasting levels. GLP-1 levels post exercise training after the single bout of exercise were significantly higher than those pre exercise training (areas under the curve (AUC); from 238.4 ± 65.2 to 286.5 ± 51.2 pmol/ml x 120 min, P < 0.001). There was a tendency for higher AUC for the time courses of PYY post exercise training than for those pre exercise training (AUC; from 519.5 ± 135.5 to 551.4 ± 128.7 pmol/ml x 120 min, P = 0.06). Changes in (delta) GLP-1 AUC were significantly correlated with decreases in body weight (r = -0.743, P < 0.001), body mass index (r = -0.732, P < 0.001), percent body fat (r = -0.731, P < 0.001), and energy intake after a single bout exercise (r = -0.649, P < 0.01) and increases in peak VO2 (r = 0.558, P < 0.05). These results suggest that the ability of exercise training to create a negative energy balance relies not only directly on its impact on energy expenditure, but also indirectly on its potential to modulate energy intake.0Comments 5Citations
- "However, most studies showed a compensatory increase in fasting ghrelin levels in response to reductions in body weight (Schubert et al. 2005; Kelishadi et al. 2008; Kim et al. 2008; Konopko-Zubrzycka et al. 2009; Leidy et al. 2004; Martins et al. 2010; Mizia-stec et al. 2008; Santosa et al. 2007). For example, whereas total ghrelin fasting levels were not affected by aerobic exercise training for 5 days without reductions in body weight (Mackelvie et al. 2007), fasting plasma levels gradually increased during 12 weeks of aerobic and resistance exercise with significant decreases in body weight and fat; and such reductions were strongly associated with increased fasting ghrelin levels (Kim et al. 2008; Leidy et al. 2004 ). For longer term exercise training where weight reductions were achieved over one year without caloric restriction, fasting ghrelin levels increased with weight loss, again suggesting a role for ghrelin in the adaptive response constraining weight loss (Schubert et al. 2005). "