Metabolic response to a mixed meal in obese and lean women from two South african populations

Obes Res. 2002 Dec;10(12):1207-16. doi: 10.1038/oby.2002.165.

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.

Research methods and procedures: 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).

Discussion: 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.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adipose Tissue
  • African Continental Ancestry Group*
  • Blood Glucose / analysis
  • Body Composition
  • Body Constitution
  • Carbon Isotopes
  • Caseins / administration & dosage
  • Dietary Fats / administration & dosage
  • Emulsions
  • European Continental Ancestry Group*
  • Fasting
  • Fatty Acids, Nonesterified / blood
  • Female
  • Food*
  • Glucose / administration & dosage
  • Glucose Tolerance Test
  • Humans
  • Insulin / blood
  • Lipids / blood
  • Middle Aged
  • Obesity / metabolism*
  • Oxidation-Reduction
  • Palmitic Acid / administration & dosage
  • South Africa
  • Sucrose / administration & dosage
  • Tomography, X-Ray Computed
  • Triglycerides / blood
  • Viscera

Substances

  • Blood Glucose
  • Carbon Isotopes
  • Caseins
  • Dietary Fats
  • Emulsions
  • Fatty Acids, Nonesterified
  • Insulin
  • Lipids
  • Triglycerides
  • Palmitic Acid
  • Sucrose
  • Glucose