Ghrelin levels before and after reduction of overweight due to a low-fat high-carbohydrate diet in obese children and adolescents

Abstract

BACKGROUND: There are conflicting results for ghrelin changes in reduction of overweight. Increasing ghrelin levels in weight reduction are considered to be responsible for compensatory mechanisms that make the reduction of overweight unlikely to be sustained. METHODS:We have analyzed fasting serum ghrelin levels, weighed dietary record and, as biochemical markers of clinically relevant reduction of overweight, leptin, adiponectin and insulin levels and insulin resistance measured by homeostasis model assessment (HOMA) at baseline and after a 1-y outpatient weight reduction program based on a high-carbohydrate and low-fat diet in 37 obese children (median age 10 y). We divided these children into two subgroups according to their degree of weight loss (substantial reduction of overweight: decrease in SDS-BMIZ0.5). Furthermore, we analyzed ghrelin levels in 16 normalweight children. RESULTS: Obese children demonstrated significant (Po0.001) lower ghrelin levels compared to normal-weight children. Daily caloric intake (P ¼ 0.004) and percentage fat content decreased significantly (Po0.001), while percentage carbohydrate content increased significantly (P ¼ 0.003) between baseline and 1-y follow-up in the obese children. The substantial reduction of overweight in 16 children (median SDS-BMI ¼ À0.7) was associated with significant changes in insulin resistance (median decrease of HOMA 27%; P ¼ 0.013), insulin (median decrease 25%, P ¼ 0.036), adiponectin (median increase 15%; P ¼ 0.003), and leptin levels (median decrease 19%; P ¼ 0.023), while there were no significant changes in ghrelin levels (median increase 4%; P ¼ 0.326). In the 21 children without substantial reduction of overweight (median SDS-BMI ¼ À0.3), there were no significant changes in insulin resistance and in insulin, adiponectin, leptin and ghrelin levels. CONCLUSIONS: We conclude that in obese children, low-fat high-carbohydrate diet-induced weight loss does not change ghrelin secretion, but significantly decreases leptin levels, increases adiponectin levels and improves insulin resistance determined by significantly decreased insulin resistance indices as well as lowered serum insulin levels.

Impact of weight loss on markers of systemic inflammation in obese Saudi children with asthma

“…Current study showed that the plasma adiponectin increases following 8 weeks of aerobic training. The changes in the level of adiponectin because of adaptation with the aerobic exercises in most of the previous studies have shown the same results as of this study 30,31,32,32,33,34 . In a study on young and middle-aged women, doing ten weeks of aerobic training resulted in an increase in the plasma levels of adiponectin alongside with a decrease in insulin resistance 30 .…”

“…While Esposito and colleagues who reported that weight loss in obese women resulted in significant decreases in previously elevated IL-6, IL-8 in addition to a significant increase in the anti-inflammatory adipokine and adiponectin 33 . Also, Reinher etal, proved that weight loss was accompanied by a 15% increase in adiponectin and 19% reduction in leptin 34 . In another study, nine overweight children performed a progressive aerobic program for 8 weeks.…”

Resistin concentrations before and after weight loss in obese children

“…This amount of weight loss led to a significant improvement of insulin resistance, cardiovascular risk factors, adiponectin, and leptin levels as demonstrated in our previous studies. [29][30][31][32] Therefore, a too small degree of weight loss seems unlikely as an explanation for the missing effect of weight loss on resistin concentrations. Since resistin is expressed at higher levels in intraabdominal than subcutaneous fat, 12,27 body fat distribution may play an important role in human resistin levels.…”

Ghrelin, Nitrite and Paraoxonase/Arylesterase Concentrations in Cement Plant Workers

“…Serum immunoreactive ghrelin levels were measu red in duplicate using a commercial radio immunoassay (RIA) that uses 125 I-labeled bioactive ghrelin as a tracer and a rabbit polyclonal antibody raised against full-length octanoylated human ghrelin (Phoenix, Europe, Karlsruhe, Germany), as described previously (25,31). The assay detects both octanoylghrelin and des-octanoyl-ghrelin.…”