Serum Fibroblast Growth Factor-21 Levels During Prolonged Fasting

Fluctuations of Serum Fibroblast Growth Factor-21 Levels During Prolonged Fasting in Male Adults

The investigators hypothesized that serum FGF21 levels would increase with prolongation of the fasting period. The investigators also hypothesized that food intake and body composition would change. The study was conducted with 12 healthy male adults. A questionnaire was administered at the beginning of the study. Anthropometric measurements, dietary intake and physical activities were recorded and blood samples were taken before, during and after Ramadan.

The aim of this study was to determine the effects of hunger on serum Fibroblast Growth Factor 21 (FGF21) levels, nutritional status and anthropometric measurements of adult males during fasting. FGF21 is a significant protein in the process of adaption to fasting due to its effects on liver, adipose tissue, and brain. A total of 12 healthy individuals with normal body mass index, between the ages of 18 to 35 participated to this cross-sectional study. All participants provided written informed consent. Sample size determined with power analysis. A questionnaire was administered in order to determine individuals' general characteristics, nutrition habits, and smoking and alcohol habits. Anthropometric measurements, 24 hours dietary recall and physical activities were recorded and blood samples were taken four times in following periods; before Ramadan, first week of Ramadan, third week of Ramadan and two weeks after Ramadan. Serum FGF21 levels were determined by ELISA (Enzyme-Linked Immunosorbent Assay). Mean energy and nutrient intake were calculated by BEBIS (Nutrition Information System) and results were compared with Recommended Dietary Allowances (RDA). Paired samples t-test and Wilcoxon-signed rank test were used to explore differences. The study was approved by Hacettepe University Non-Interventional Clinical Research Ethics Board.

Inclusion Criteria:

• Being healthy male,
• Being between the ages of 19-35,
• Fasting regularly during Ramadan.

Exclusion Criteria:

• Being females,
• Being younger than 19 years and older than 35 years of age,
• Having a BMI less than 18.5 kg/m2 and greater than 24.9 kg/m2,
• Having any chronic metabolic disease,
• Individuals who not fast regularly during Ramadan.