Liver enzymes but not free fatty acid levels predict markers of insulin sensitivity in overweight and obese, nondiabetic adults.
Although obesity is a key predisposing risk factor in the development of insulin resistance (IR) and type 2 diabetes mellitus, not all obese individuals develop IR. This study aimed to identify key anthropometric and biochemical parameters that predict insulin sensitivity in overweight and obese adults. Based on previous literature, we hypothesized that markers of insulin sensitivity would be negatively correlated with plasma concentrations of free fatty acids and liver enzymes. Forty nondiabetic adult participants (body mass index ≥ 25.0 kg/m²) were recruited. Data collection included anthropometric measurements and fasting plasma samples for the quantification of liver enzymes (alanine transaminase, aspartate transaminase, γ-glutamyl transpeptidase), blood lipid profile, and markers of insulin sensitivity. Questionnaires relating to dietary intake, physical activity, and fatigue were also completed. Insulin and Homeostasis Model of Assessment (HOMA) scores were significantly correlated with indirect measures of central obesity (P < .05). Glycosylated hemoglobin, insulin, and HOMA scores for IR were all positively correlated with selected liver function markers (P < .05). Scores of HOMA-IR were significantly positively correlated with plasma phospholipid levels of n-3 fatty acids (P = .04) and ratio of n-3/n-6 fatty acids (P < .05) and negatively correlated with n-6 fatty acids (P = .03). No significant correlations were found between markers of insulin sensitivity and cholesterol levels, physical activity, or self-reported fatigue. These results have reinforced the integral role of liver function in the development of IR. Despite previous data linking elevations in free fatty acid to the development of IR, we found no relationship between these variables in this study.
Children's Nutrition Research Centre, Queensland Children's Medical Research Institute, The University of Queensland, Royal Children's Hospital, Herston, Queensland, Australia; Centre for Integrative Clinical and Molecular Medicine, School of Medicine, The University of Queensland, Princess Alexandra Hospital, Woolloongabba, Queensland, Australia; School of Medicine, The University of Queensland, Adelaide, South Australia, Australia.
Belinda
B
Gray
Beverly Sara
BS
Muhlhausler
Peter Stephen Wynford
PS
Davies
Luis
L
Vitetta
D000328:Adult; D000410:Alanine Transaminase / Q000097:blood; D001219:Aspartate Aminotransferases / Q000097:blood; D015415:Biomarkers / Q000097:blood; D015992:Body Mass Index; D002784:Cholesterol / Q000097:blood; D003920:Diabetes Mellitus; D015444:Exercise / Q000502:physiology; D005221:Fatigue / Q000378:metabolism; D005230:Fatty Acids, Nonesterified / Q000097:blood*; D015525:Fatty Acids, Omega-3 / Q000097:blood; D043371:Fatty Acids, Omega-6 / Q000097:blood; D005260:Female; D006442:Glycated Hemoglobin / Q000378:metabolism*; D006801:Humans; D007328:Insulin / Q000097:blood*; D007333:Insulin Resistance; D008099:Liver / Q000201:enzymology / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000097:blood / Q000201:enzymology / Q000503:physiopathology*; D056128:Obesity, Abdominal / Q000097:blood / Q000201:enzymology / Q000503:physiopathology; D050177:Overweight; D010743:Phospholipids / Q000097:blood; D012016:Reference Values; D005723:gamma-Glutamyltransferase / Q000097:blood
D000410:Alanine Transaminase; D001219:Aspartate Aminotransferases; D015415:Biomarkers; D002784:Cholesterol; D005230:Fatty Acids, Nonesterified; D015525:Fatty Acids, Omega-3; D043371:Fatty Acids, Omega-6; D006442:Glycated Hemoglobin; D007328:Insulin; D010743:Phospholipids; D005723:gamma-Glutamyltransferase
ALT; AST; BMI; CV; DHA; EPA; FFAs; GGT; HOMA; Homeostasis Model of Assessment; Human; ICAM-1; IR; Insulin; LDL; Liver; NQSP; National Glycohemoglobin Standardization Program; Obesity; PUFA; Spearman correlation coefficients; T2DM; WC; WHtR; alanine transaminase; aspartate transaminase; body mass index; coefficients of variation; docosahexaenoic acid; eGFR; eicosapentaenoic acid; estimated glomerular filtration rate; free fatty acids; insulin resistance; intercellular adhesion molecule 1; low-density lipoprotein; n-3 Fatty acids; n-6 Fatty acids; polyunsaturated fatty acids; r; type 2 diabetes mellitus; waist circumference; waist-to-height ratio; γ-glutamyl transpeptidase