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Impact of fat, protein, and glycemic index on postprandial glucose control in type 1 diabetes: implications for intensive diabetes management in the continuous glucose monitoring era.
Bell, KJ, Smart, CE, Steil, GM, Brand-Miller, JC, King, B, Wolpert, HA
Diabetes care. 2015;(6):1008-15
Abstract
BACKGROUND Continuous glucose monitoring highlights the complexity of postprandial glucose patterns present in type 1 diabetes and points to the limitations of current approaches to mealtime insulin dosing based primarily on carbohydrate counting. METHODS A systematic review of all relevant biomedical databases, including MEDLINE, Embase, CINAHL, and the Cochrane Central Register of Controlled Trials, was conducted to identify research on the effects of dietary fat, protein, and glycemic index (GI) on acute postprandial glucose control in type 1 diabetes and prandial insulin dosing strategies for these dietary factors. RESULTS All studies examining the effect of fat (n = 7), protein (n = 7), and GI (n = 7) indicated that these dietary factors modify postprandial glycemia. Late postprandial hyperglycemia was the predominant effect of dietary fat; however, in some studies, glucose concentrations were reduced in the first 2-3 h, possibly due to delayed gastric emptying. Ten studies examining insulin bolus dose and delivery patterns required for high-fat and/or high-protein meals were identified. Because of methodological differences and limitations in experimental design, study findings were inconsistent regarding optimal bolus delivery pattern; however, the studies indicated that high-fat/protein meals require more insulin than lower-fat/protein meals with identical carbohydrate content. CONCLUSIONS These studies have important implications for clinical practice and patient education and point to the need for research focused on the development of new insulin dosing algorithms based on meal composition rather than on carbohydrate content alone.
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Effect of the glycemic index of carbohydrates on day-long (10 h) profiles of plasma glucose, insulin, cholecystokinin and ghrelin.
Reynolds, RC, Stockmann, KS, Atkinson, FS, Denyer, GS, Brand-Miller, JC
European journal of clinical nutrition. 2009;(7):872-8
Abstract
BACKGROUND Low glycemic index (GI) carbohydrates have been linked to increased satiety. The drive to eat may be mediated by postprandial changes in glucose, insulin and gut peptides. OBJECTIVE To investigate the effect of a low and a high GI diet on day-long (10 h) blood concentrations of glucose, insulin, cholecystokinin (CCK) and ghrelin (GHR). DESIGN Subjects (n=12) consumed a high and a low GI diet in a randomized, crossover design, consisting of four meals that were matched for macronutrients and fibre, and differed only in carbohydrate quality (GI). Blood was sampled every 30-60 min and assayed for glucose, insulin, CCK and GHR. RESULTS The high GI diet resulted in significantly higher glucose and insulin mean incremental areas under the curve (IAUC, P=0.027 and P=0.001 respectively). CCK concentration was 59% higher during the first 7 h of the low GI diet (394+/-95 pmol/l min) vs the high GI diet (163+/-38 pmol/l min, P=0.046), but there was no difference over 10 h (P=0.224). GHR concentration was inversely correlated with insulin concentration (Pearson correlation -0.48, P=0.007), but did not differ significantly between the low and high GI diets. CONCLUSIONS Mixed meals of lower GI are associated with lower day-long concentrations of glucose and insulin, and higher CCK after breakfast, morning tea and lunch. This metabolic profile could mediate differences in satiety and hunger seen in some, but not all, studies.
3.
Can a low-glycemic index diet reduce the need for insulin in gestational diabetes mellitus? A randomized trial.
Moses, RG, Barker, M, Winter, M, Petocz, P, Brand-Miller, JC
Diabetes care. 2009;(6):996-1000
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Abstract
OBJECTIVE A low-glycemic index diet is effective as a treatment for individuals with diabetes and has been shown to improve pregnancy outcomes when used from the first trimester. A low-glycemic index diet is commonly advised as treatment for women with gestational diabetes mellitus (GDM). However, the efficacy of this advice and associated pregnancy outcomes have not been systematically examined. The purpose of this study was to determine whether prescribing a low-glycemic index diet for women with GDM could reduce the number of women requiring insulin without compromise of pregnancy outcomes. RESEARCH DESIGN AND METHODS All women with GDM seen over a 12-month period were considered for inclusion in the study. Women (n = 63) were randomly assigned to receive either a low-glycemic index diet or a conventional high-fiber (and higher glycemic index) diet. RESULTS Of the 31 women randomly assigned to a low-glycemic index diet, 9 (29%) required insulin. Of the women randomly assigned to a higher-glycemic index diet, a significantly higher proportion, 19 of 32 (59%), met the criteria to commence insulin treatment (P = 0.023). However, 9 of these 19 women were able to avoid insulin use by changing to a low-glycemic index diet. Key obstetric and fetal outcomes were not significantly different. CONCLUSIONS Using a low-glycemic index diet for women with GDM effectively halved the number needing to use insulin, with no compromise of obstetric or fetal outcomes.