title: Metabolic response to a mixed meal in obese and lean women from two South african populations.
abstract: OBJECTIVE
  Lower lipid and insulin levels are found during a glucose-tolerance test in obese black than obese white South African women. Therefore, beta-cell function and lipid metabolism were compared in these populations during a mixed meal.
  
  
  METHODS
  Blood concentrations of glucose, free fatty acids (FFAs), insulin, lipograms, and in vivo FFA oxidation were determined at fasting and for 7 hours after oral administration of a mixed emulsion containing glucose-casein-sucrose-lipid and [1-(13)C] palmitic acid in 8 lean black women (LBW), 10 obese black women (OBW), 9 lean white women (LWW), and 10 obese white women (OWW). Subcutaneous and visceral fat mass was assessed by computerized tomography.
  
  
  RESULTS
  Visceral fat area was higher in OWW (152.7 +/- 17.0 cm(2)) than OBW (80.0 +/- 6.7 cm(2); p < 0.01). In OBW, 30-minute insulin levels were higher (604.3 +/- 117.6 pM) than OWW (311.0 +/- 42.9 pM; p < 0.05). Total triglyceride was higher in OWW (706.7 +/- 96.0 mM x 7 hours) than OBW (465.7 +/- 48.2 mM x 7 hours; p < 0.05) and correlated with visceral fat area (beta = 0.38, p = 0.05). Palmitate oxidation was higher in lean than obese women in both ethnic groups and correlated negatively with fat mass (beta = -0.58, p < 0.005).
  
  
  CONCLUSIONS
  The higher 30-minute insulin response in OBW may reflect a higher insulinotropic effect of FFAs or glucose. The elevated triglyceride level of OWW may be due to their higher visceral fat mass and possibly reduced clearance by adipose tissue.
authors.affiliation: Department of Chemical Pathology, National Health Laboratory Service, University of the Witwatersrand Faculty of Health Sciences, Johannesburg, South Africa.
authors.forename: Chamindie
authors.initials: C
authors.lastname: Punyadeera
authors.forename: Nigel J
authors.initials: NJ
authors.lastname: Crowther
authors.forename: Maria-Terésa
authors.initials: MT
authors.lastname: van der Merwe
authors.forename: Marketa
authors.initials: M
authors.lastname: Toman
authors.forename: Andrew Ronnie
authors.initials: AR
authors.lastname: Immelman
authors.forename: Glen P
authors.initials: GP
authors.lastname: Schlaphoff
authors.forename: Ian Peter
authors.initials: IP
authors.lastname: Gray
mesh_terms: D000273:Adipose Tissue; D044383:Black People; D001786:Blood Glucose / Q000032:analysis; D001823:Body Composition; D001824:Body Constitution; D002247:Carbon Isotopes; D002364:Caseins / Q000008:administration & dosage; D004041:Dietary Fats / Q000008:administration & dosage; D004655:Emulsions; D005215:Fasting; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005260:Female; D005502:Food; D005947:Glucose / Q000008:administration & dosage; D005951:Glucose Tolerance Test; D006801:Humans; D007328:Insulin / Q000097:blood; D008055:Lipids / Q000097:blood; D008875:Middle Aged; D009765:Obesity / Q000378:metabolism*; D010084:Oxidation-Reduction; D019308:Palmitic Acid / Q000008:administration & dosage; D013019:South Africa; D013395:Sucrose / Q000008:administration & dosage; D014057:Tomography, X-Ray Computed; D014280:Triglycerides / Q000097:blood; D014781:Viscera; D044465:White People
chemical_list: D001786:Blood Glucose; D002247:Carbon Isotopes; D002364:Caseins; D004041:Dietary Fats; D004655:Emulsions; D005230:Fatty Acids, Nonesterified; D007328:Insulin; D008055:Lipids; D014280:Triglycerides; D019308:Palmitic Acid; D013395:Sucrose; D005947:Glucose