Dr Melony Fortuin-de Smidt

Her research project is titled “The effect of exercise training on insulin secretion and sensitivity in obese black South African.” The escalating prevalence of type 2 diabetes among black individuals, who are at particular risk for type 2 diabetes, insulin resistance, and hyperinsulinemia is concerning. However, the mechanisms are still not fully understood. Therefore, the research aim is to use exercise as a model to explore changes in insulin sensitivity, hyperinsulinemia and pancreatic beta cell function and to determine whether these changes are associated with body composition, body fat distribution and hepatic, pancreatic and skeletal muscle fat deposition. Her research group conducted a randomized controlled exercise intervention study enrolling 45 healthy, young (20–35 years old), black (self-reported Xhosa descent), obese (BMI 30–40 kg/m2) women. The exercise group (n=23) participated in a 12-week supervised moderate-vigorous aerobic and resistance training intervention. Heart rate was monitored to ensure that the prescribed exercise intensity was achieved. The control group (n=22) was asked to continue with habitual dietary and physical activity. Energy expenditure and diet were monitored at 4-weekly intervals. Pre- and post-intervention testing included:

  1. A frequently sampled intravenous glucose tolerance test - glucose, insulin and c-peptide were measured at various time points over 4 hours. Mathematical modelling was then used to obtain measures of insulin sensitivity, insulin secretion in response to glucose, and hepatic insulin extraction.
  2. Magnetic resonance imaging to determine abdominal subcutaneous and visceral adipose tissue, hepatic, pancreatic and skeletal muscle fat content.
  3. Whole body DXA scan to determine total body, trunk and leg fat mass. 
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