Weight-related differences in glucose metabolism and free fatty acid production in two South African population groups

Punyadeera, C., van der Merwe, M. T., Crowther, N. J., Toman, M., Immelman, A. R., Schlaphoff, G. P. and Gray, I. P. (2001) Weight-related differences in glucose metabolism and free fatty acid production in two South African population groups. International Journal of Obesity, 25 8: 1196-1205. doi:10.1038/sj.ijo.0801660

Author Punyadeera, C.
van der Merwe, M. T.
Crowther, N. J.
Toman, M.
Immelman, A. R.
Schlaphoff, G. P.
Gray, I. P.
Title Weight-related differences in glucose metabolism and free fatty acid production in two South African population groups
Journal name International Journal of Obesity   Check publisher's open access policy
ISSN 0307-0565
Publication date 2001-08
Sub-type Article (original research)
DOI 10.1038/sj.ijo.0801660
Volume 25
Issue 8
Start page 1196
End page 1205
Total pages 10
Place of publication London, United Kingdom
Publisher Nature Publishing
Language eng
Formatted abstract
OBJECTIVE: The effects of free fatty acids (FFA), leptin, tumour necrosis factor (TNF) α and body fat distribution on in vivo oxidation of a glucose load were studied in two South African ethnic groups.

DESIGN AND MEASUREMENTS: Anthropometric and various metabolic indices were measured at fasting and during a 7 h oral glucose tolerance test (OGTT). Body composition was measured using bioelectrical impedance analysis and subcutaneous and visceral fat mass was assessed using a five- and two-level CT-scan respectively. Glucose oxidation was evaluated by measuring the ratio of 13CO 2 to 12CO 2 in breath following ingestion of 1- 13C-labelled glucose.

SUBJECTS: Ten lean black women (LBW), ten obese black women (OBW), nine lean white women (LWW) and nine obese white women (OWW) were investigated after an overnight fast.

RESULTS: Visceral fat levels were significantly higher (P < 0.01) in obese white than black women, despite similar body mass indexes (BMIs). There were no ethnic differences in glucose oxidation however; in the lean subjects of both ethnic groups the area under the curve (AUC) was higher than in obese subjects (P < 0.05 for both) and was found to correlate negatively with weight (r = -0.69, P < 0.01) after correcting for age. Basal TNFα concentrations were similar in all groups. Percentage suppression of FFAs at 30min of the OGTT was 24 ± 12% in OWW and -38 ± 23% (P < 0.05) in OBW, ie the 30min FFA level was higher than the fasting level in the latter group. AUC for FFAs during the late postprandial period (120-420 min) was significantly higher in OWW than OBW (P < 0.01) and LWW (P < 0.01) and correlated positively with visceral fat mass independent of age (r = 0.78, P < 0.05) in the OWW only. Leptin levels were higher (P < 0.01) both at fasting and during the course of the OGTT in obese women from both ethnic groups compared to the lean women.

CONCLUSIONS: Glucose oxidation is reduced in obese subjects of both ethnic groups; inter- and intra-ethnic differences were observed in visceral fat mass and FFA production and it is possible that such differences may play a role in the differing prevalences of obesity-related disorders that have been reported in these two populations.
Keyword Glucose oxidation
Free fatty acids
Visceral fat
Ethnic differences
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Non-UQ

Document type: Journal Article
Sub-type: Article (original research)
Collection: Australian Institute for Bioengineering and Nanotechnology Publications
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