Masking of diabetic phenotype on a low-energy diet despite persistence of impaired insulin response.
Type 2 diabetes has been postulated to be a "thrifty genotype" that aids fuel conservation; to investigate this hypothesis, type 2 diabetic and nondiabetic subjects, normal weight and obese, were studied after both 6 days on a 700-calorie diet and 6 days on a 2,800-calorie diet. On 2,800 calories per day, the median basal plasma glucose was raised in diabetics compared with nondiabetic subjects (median, 5.5 and 4.5 mmol/L, respectively; P = .003), but on the low-energy diet there was no difference (4.1 and 3.7 mmol/L, respectively; P greater than .05). Basal plasma insulin levels were similar in the diabetic and nondiabetic subjects and were twofold to threefold higher on the high- than low-energy diet in both diabetic (median, 7.8 and 3.1 mU/L on high- and low-energy diets, respectively; P = .007) and nondiabetic subjects (6.8 and 2.6 mU/L, respectively; P = .005). Similarly, the postprandial insulin concentrations increased to the same degree on the high- compared with the low-energy diet in diabetic (median postprandial increment, 14.9 and 3.4 mU/L; P = .005) and nondiabetic patients (9.5 and 3.0 mU/L; P = .005) and the beta cells in type 2 diabetes appeared to modulate normally to different calorie intakes. On both diets, the diabetic subjects had an impaired first-phase insulin response to an intravenous glucose load compared with nondiabetic subjects (high-energy diet median first-phase increment, 4.3 and 21.2 mU/L in diabetic and nondiabetic subjects, P = .0007; low-energy diet, 4.0 and 20.4 mU/L, respectively, P = .003).(ABSTRACT TRUNCATED AT 250 WORDS)
Levy
J C
JC
Diabetes Research Laboratories, Radcliffe Infirmary, Oxford, UK.
Ward
G M
GM
Naylor
B A
BA
Williamson
D H
DH
Turner
R C
RC
D000328:Adult; D000368:Aged; D001786:Blood Glucose / Q000032:analysis; D003920:Diabetes Mellitus / Q000097:blood / Q000235:genetics* / Q000378:metabolism; D004032:Diet; D004435:Eating / Q000502:physiology; D004734:Energy Metabolism; D005260:Female; D005947:Glucose / Q000378:metabolism / Q000494:pharmacology; D005951:Glucose Tolerance Test; D006801:Humans; D007275:Injections, Intravenous; D007328:Insulin / Q000097:blood / Q000378:metabolism*; D000078790:Insulin Secretion; D007657:Ketone Bodies / Q000097:blood; D008297:Male; D008875:Middle Aged; D009994:Osmolar Concentration; D010641:Phenotype
D001786:Blood Glucose; D007328:Insulin; D007657:Ketone Bodies; D005947:Glucose