Studying the serum ghrelin levels of the elite athletes and sedentary controls fasting at the time of Ramadan

TurkishJournal of SportandExercise http://selcukbesyod.selcuk.edu.tr/sumbtd/index Year: 2014 - Volume: 16 - Issue: 1 - Pages: 25-31 DOI:10.15314/TJSE.201416015 ISSN: 2147-5652 Studying the serum ghrelin levels of the elite athletes and sedentary controls fasting at the time of Ramadan Hasan EKER1, Ibrahim CICIOGLU2, Ilhan YETKIN3, Ozlem GULBAHAR4, C. Berkan Alpay5 1Department of Physical Education and Sports,Hitit University, Turkey. 2Department of Physical Education and Sports, Gazi University, Turkey. 3Department of Medicine, Division of Metabolism, Endocrinology and Nutrition, Gazi University, Turkey. 4Department of Biochemistry Lab., Gazi University, Turkey. 5Department of Physical Education and Sports, Nigde University, Turkey. Address correspondence to Hasan Eker, . Abstract The Ghrelin is produced primarily by enteroendocrine cells in the gastric mucosa, and increases gastric emptying in normal subjects. The purpose of this study is to determine the differences in the Ghrelin level during different times along the day, and to assess the differences between the athletes and sedentary at the end of Ramadan fasting period of one month. The results indicated that there were no significant difference among the Ghrelin levels of athletes and sedentary during different times through the day (p>0.05). Significant differences were observed between pre- and post-tests mean Ghrelin scores of subjects (p<0.05) without making a separation as an athlete and sedentary. Also, the results indicated no significant difference between repeated Ghrelin measurements of athletes and sedentary (p>0.05). A significant and positive relationship was found in the middle level at the percentages of BMI and body fat of both groups. Moreover, there were significant differences among BMI scores (p<0.01) and body fat % (p<0.05) of the athletes and sedentary. Consequently, fasting during Ramadan did not cause any differentiation on the serum Ghrelin level of athletes and sedentary, but without group differentiation there was significant increase from the initial measurement to the last measurement of the serum Ghrelin level. There was a significant and positive relationship at middle level between BMI and body fat % of both groups of athletes and sedentary. There was a significant relationship, on the other hand, between BMI and repeated Ghrelin measurements of subjects. Keywords: Athletes, Ramadan, fasting, ghrelin. INTRODUCTION Each year during the lunar month of Ramadan, adult Muslims refrain from eating, drinking, smoking or having sexual relationships during the daytime. This fasting is complete, intermittent, and does not require caloric restriction. Free eating is allowed from sunset to dawn. Since Ramadan is a lunar month, its occurrence changes with time. Each year the Ramadan month occurs 11 days earlier. Consequently, each 9 years, Ramadan happens in a different season; the length and the temperature of the fasting days also change (1). During the last 20 years, several studies were undertaken to elucidate the effects of Ramadan fasting in healthy subjects. Ghrelin, a peptide secreted by endocrine cells in the gastrointestinal tract, is thought to play a significant role in the regulation of energy balance due to its effects on the stimulation of food intake (27,28) and weight gain (5,24,27,28) in rodents. It has been suggested that ghrelin may also play a role in meal initiation in humans, since the concentration of ghrelin increases immediately prior to a meal (5) and decreases after eating (5,7,25). In addition to having a powerful effect on the secretion of growth hormone, ghrelin stimulates food intake and transduces signals to hypothalamic regulatory nuclei that control energy homeostasis. Thus, it is interesting to note that the stomach may play an important role in digestion and central feeding regulation (11). Furthermore, ghrelin infusions are associated with feelings of hunger and increased energy intake during a buffet-style lunch (26). Despite the evidence indicating a role in acute food intake, little is known about the factors regulating ghrelin and its effects on long-term energy balance in humans. One hypothesis is that ghrelin secretion is up-regulated in periods of Eker et al. 2014 negative energy balance and down-regulated in periods of positive energy balance (20). Since energy balance is a function of both energy intake and energy consumption, Ghrelin concentrations should increase or decrease with fluctuations in food intake (macronutrient composition and/or energy intake) and/or energy expenditure. In turn, decreased ghrelin concentrations should be associated with lower food intake. However, the effects of monthly change in food intake and energy expenditure on ghrelin have not been investigated in humans. Ghrelin stimulates secretion of GH, food intake, and body weight gain when administrated peripherally or centrally (2,24). Ghrelin activates neuropeptide Y (NPY) and agouti-related protein (AGRP)- producing neurons localized in the arcuate nucleus of the hypothalamus (3,13,19,21), which is one of the brain regions of primary importance in the regulation of feeding. The secretion of ghrelin increases under conditions of negative energy balance, such as starvation, cachexia, and anorexia nervosa, whereas its expression decreases under conditions of positive energy balance, such as feeding, hyperglycemia, and obesity (18,24). Obesity and related disorders are among the leading causes of illness and mortality in the developed world (17). The problem of obesity has reached epidemic proportions in the United States. More than 50% of adults are overweight or obese, and 5% are severely obese (body mass index [BMI]>35) (8). In Turkey in 2000, the prevalence of obesity was 22.3% (BMI>30) (4). In 2004, this prevalence was 25.2% (36.7% in women, and 21.6% in men) (9). To better understand the pathophysiological mechanisms that underlie metabolic disorders, increasing attention has been paid to central regulatory elements in energy homeostasis, including food intake and energy expenditure. The purpose of this study was to determine Ghrelin level differences during different times through the day and to assess differences among the athletes and sedentaries at the end of Ramadan fasting period that was one month. In this study, a critical analysis of these results was undertaken in order to elucidate the Ramadan effects on ghrelin parameters of changes. Turk J SportExe 2014; 16(1): 25–31 © 2014 Department of PhysicalEducationandSport, SelcukUniversity MATERIALS & METHODS Subjects The study exclusion criteria were totally 30 male subjects who were 15 elite physically active athletes and 15 sedentary university students. The volunteers who fast during Ramadan have been taken into consideration in the study. The mean age, height and body weight of subjects were as follows: 21.33 ± 2.58 yrs., 173.0 ± 8.08 cm, 75.80 ± 15.15 kg for athletes, and 19.86 ± 1.72 yrs, 172.5 (...truncated)