Diet treatment of newly presenting type 2 diabetes improves insulin secretory capacity, but has no effect on insulin sensitivity.
Fifteen newly diagnosed obese Type 2 diabetic subjects were treated with diet alone for 3 months with a median 1.5 kg weight loss. Each had a Continuous Infusion of Glucose with Model Assessment (CIGMA) test, at diagnosis and at 3 months, measuring insulin and C-peptide responses, and deriving mathematically modelled measures of beta-cell function and insulin sensitivity. Median fasting glucoses were 9.6 mmol l-1 at diagnosis and 8.5 mmol l-1 at 3 months (NS). Median fasting insulin was 9.3 mU l-1 at diagnosis and 11.7 mU l-1 at 3 months (NS). Median fasting C-peptide was 0.58 nmol l-1 at diagnosis and 0.64 nmol l-1 at 3 months (p < 0.05). Median achieved plasma insulin increased from 13.8 mU l-1 at diagnosis to 17 mU l-1 at 3 months (p < 0.02); median achieved plasma C-peptide increased from 0.72 nmol l-1 at diagnosis to 0.81 nmol l-1 at 3 months (p < 0.002). Modelled beta-cell function rose from median 26% at diagnosis to 37% at 3 months (p < 0.02). Modelled insulin sensitivity showed no significant change (median 0.31 at diagnosis, 0.27 at 3 months, NS). Elevation of achieved C-peptide was positively correlated with weight loss (Rs = 0.53, p < 0.05), but not with change in fasting glucose. Diet treatment of newly diagnosed Type 2 diabetes, with modest weight loss, results primarily in improvement of insulin secretory capacity, rather than insulin sensitivity.
Hosker
J P
JP
Department of Medicine, Manchester Royal Infirmary, UK.
Kumar
S
S
Gordon
C
C
Bhatnagar
D
D
France
M
M
Boulton
A J
AJ
D000328:Adult; D001786:Blood Glucose / Q000032:analysis; D002096:C-Peptide / Q000097:blood / Q000378:metabolism; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000178:diet therapy* / Q000503:physiopathology*; D005215:Fasting; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005260:Female; D015309:Glucose Clamp Technique; D006029:Glycosuria; D006801:Humans; D007328:Insulin / Q000097:blood / Q000378:metabolism*; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D013997:Time Factors
D001786:Blood Glucose; D002096:C-Peptide; D005230:Fatty Acids, Nonesterified; D007328:Insulin