Effects of Weight Loss on FGF-21 in Human Subjects: An Exploratory Study

Abstract

Fibroblast growth factor-21 (FGF-21), is a protein involved in cell growth and differentiation, development, wound repair and metabolism. Research looking at the impact of weight loss on FGF-21 levels is limited. The objective of this exploratory study was to determine changes in serum FGF-21 levels following weight loss induced by either continuous energy restriction or intermittent energy restriction. A sub cohort of participants who completed a 12-month dietary intervention trial following continuous energy restriction, or a week-on week-off energy restriction pattern, were selected for analysis. FGF-21 levels were not altered by weight loss and were not correlated with body weight or BMI at baseline or 12 months. Weight loss after 12 months either through continuous energy restriction or intermittent energy restriction was −5.9 ± 4.5 and −4.9 ± 3.4 kg, respectively. There was no change in FGF-21 levels, 0.3 ± 0.9 and 0.04 ± 0.2 ng/mL (p = 0.2). In conclusion, weight loss in healthy overweight or obesity subjects did not affect FGF-21 levels.

The Effect of Caloric Restriction with and without n-3 PUFA Supplementation on Bone Turnover Markers in Blood of Subjects with Abdominal Obesity: A Randomized Placebo-Controlled Trial

“…However, in the current trial, weight loss did not result in a change in serum FGF-21. Similar to our study, Headland et al also reported no change in blood FGF-21 concentration in individuals following an energy restriction diet (of 1000 kcal/day for women or 1300 kcal/day for men) for 12 months [33]. In the present study, there was also no change in serum osteopontin, a multifunctional protein which is distributed in many tissues and fluids.…”

Close association between lifestyle and circulating FGF21 levels: A systematic review and meta-analysis

“…Overall, CRIWL significantly decreased the cFGF21 level (SMD=-0.51 pg/ml, 95%CI: -0.92 to -0.09, p=0.02) ( Figure 5 ). Among them, cFGF21 concentrations were significantly lower in individuals who underwent hypocaloric diets with relatively high protein contents (≥30% diet calorie from protein, ≥30E% protein) than their cFGF21 levels before the diets ( 32 – 36 ) (p=0.003); while CR with <30E% protein ( 36 – 40 ) or CR with unspecified protein content ( 32 , 41 , 42 ) did not significantly affected the cFGF21 level ( Figure 5 , p=0.30 and p=0.12 respectively). The heterogeneity among these studies was significant (p<0.00001).…”

“…Eleven studies containing 367 individuals were involved in the analysis of the association between calorie restriction (CR)-induced weight loss (CRIWL) and cFGF21 concentration ( 32 – 42 ) ( Table 4 ). Overall, CRIWL significantly decreased the cFGF21 level (SMD=-0.51 pg/ml, 95%CI: -0.92 to -0.09, p=0.02) ( Figure 5 ).…”

“…Obesity is associated with elevated levels of cFGF21, and the expected beneficial effects of FGF21 for improving glucose tolerance and reducing plasma glucose and triglyceride levels are attenuated or even lost in obesity, suggesting the existence of an FGF21-resistant state ( 84 ). The effects of CRIWL on the cFGF21 level have been conflicting, with many factors involved, such as the number and type of participants, type of dietary intervention, time frame following intervention type and outcome measurement, and amount of weight loss ( 42 ). In this meta-analysis, 11 studies containing 373 individuals were involved in the analysis of the association between CRIWL and cFGF21 concentration ( Table 4 ).…”

“…Among all the factors that could affect the CRIWL-induced cFGF21 change, we found that the protein content in the diet could be a key factor with a 30% calorie from protein as a cutoff value. Most of the CRIWL-decreased cFGF21 results were obtained with relatively high dietary protein contents (≥30E% protein) ( 32 – 36 ), while controversial results were obtained with relatively low dietary protein contents (<30E% protein) ( 36 – 40 ) or with diets with unspecified protein contents ( 32 , 41 , 42 ).…”