Postprandial changes in glucose oxidation and insulin sensitivity in metabolic syndrome: Influence of fibroblast growth factor 21 and vitamin D status

Kaveri Pathak; Mario J Soares; Yun Zhao; Anthony P James; Jillian L Sherriff; Philip Newsholme

doi:10.1016/j.nut.2016.12.007

Postprandial changes in glucose oxidation and insulin sensitivity in metabolic syndrome: Influence of fibroblast growth factor 21 and vitamin D status

Nutrition. 2017 May:37:37-42. doi: 10.1016/j.nut.2016.12.007. Epub 2016 Dec 26.

Authors

Kaveri Pathak¹, Mario J Soares², Yun Zhao³, Anthony P James¹, Jillian L Sherriff¹, Philip Newsholme⁴

Affiliations

¹ Food, Nutrition & Health, School of Public Health, Curtin Health Innovation Research Institute, Faculty of Health Sciences, Curtin University, Perth, Western Australia.
² Food, Nutrition & Health, School of Public Health, Curtin Health Innovation Research Institute, Faculty of Health Sciences, Curtin University, Perth, Western Australia. Electronic address: m.soares@curtin.ed.au.
³ Occuptation and the Environment, School of Public Health, Faculty of Health Sciences, Curtin University, Perth, Western Australia.
⁴ School of Biomedical Science, Curtin Health Innovation Research Institute, Curtin University, Perth, Western Australia.

PMID: 28359360
DOI: 10.1016/j.nut.2016.12.007

Abstract

Objective: Metabolic inflexibility due to insulin resistance has been reported in metabolic syndrome (MetS). Fibroblast growth factor 21 (FGF21) and vitamin D status may improve insulin sensitivity. The aim of this study was to investigate glucose-induced thermogenesis and oxidation in MetS, and to examine whether changes in FGF21 or prevailing vitamin D status modulated defined metabolic parameters.

Methods: Forty-eight overweight and obese older adults (14 men, 34 women; ages 51 ± 15 y) were studied. Resting metabolic rate (RMR) and respiratory quotient (RQ) were measured before and intermittently for 2 h after an oral glucose tolerance test (OGTT). The total area under the curve (TAUC) was calculated. Insulin sensitivity index (ISI) was determined as 10⁴/(insulin × glucose) for fasting and 2 h venous blood. Fat mass (FM) and fat free mass (FFM) were measured by dual-energy x-ray absorptiometry. Participants were grouped by metabolic syndrome (MetS+ for disease presence; MetS- when no disease was present) and by median 25 hydroxyvitamin D (OHD) concentration as VD_low and VD_high. 25 OHD was also tested as a continuous variable. A parsimonious 2 × 2 analysis of variance included age, FM, FFM and MetS × sex interaction.

Results: Adjusted RMR was similar between groups but an interactive effect of MetS and sex was noted. Fasting RQ was significantly different between vitamin groups (VD_low: 0.835 ± 0.008 versus VD_high: 0.810 ± 0.008; P = 0.024) and fasting ISI was significantly greater in MetS- compared with MetS+ (P = 0.037). Postglucose increases in thermogenesis, RQ, and FGF21 were significant, but ISI decreased. Adjusted postprandial TAUC_RQ (VD_low: 1.71 ± 0.01; VD_high: 1.74 ± 0.001; P = 0.041) and ISI_2 h (VD_low: 35.41 ± 0.21; VD_high: 101.90 ± 0.21; P = 0.001) were significantly different. Adjusted FGF21 was similar across all comparisons before and after OGTT.

Conclusions: Higher vitamin D status, but not FGF21, was associated with greater postprandial glucose oxidation and improved insulin sensitivity.

Keywords: Fibroblast growth factor 21; Metabolic flexibility; Metabolic syndrome; Respiratory quotient; Vitamin D.

MeSH terms

Absorptiometry, Photon
Adolescent
Adult
Aged
Basal Metabolism
Blood Glucose / metabolism*
Body Composition
Body Mass Index
Fasting
Female
Fibroblast Growth Factors / blood*
Glucose Tolerance Test
Humans
Insulin / blood
Insulin Resistance*
Male
Metabolic Syndrome / blood*
Middle Aged
Obesity / blood
Overweight / blood
Postprandial Period*
Respiratory Rate
Sample Size
Vitamin D / administration & dosage
Vitamin D / blood*
Young Adult

Substances

Blood Glucose
Insulin
fibroblast growth factor 21
Vitamin D
Fibroblast Growth Factors