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We examined the impact of APOE genotype on plasma lipids and glucose in a secondary analysis of data from a five-arm, randomised controlled, parallel dietary intervention trial ('RISCK' study), to investigate the impact of replacing saturated fatty acids (SFA) with either monounsaturated fat (MUFA) or carbohydrate of high or low glycaemic index (GI) on CVD risk factors and insulin sensitivity. We tested the impact of APOE genotype (carriage of E2 and E4 alleles versus E3/E3), determined retrospectively, on plasma lipids, lipoproteins and glucose homeostasis at baseline ( n = 469), and on the change in these variables after 24 weeks of dietary intervention ( n = 389). At baseline, carriers of E2 ( n = 70), E4 ( n = 125) and E3/E3 ( n = 274) expressed marked differences in total plasma cholesterol (TC, p = 0.001), low density lipoprotein cholesterol (LDL-C, p < 0.0001), apolipoprotein B (apo B, p < 0.0001) and total to high density lipoprotein cholesterol ratio (TC:HDL-C, p = 0.002), with plasma concentrations decreasing in the order E4 > E3/E3 > E2. Following intervention, there was evidence of a significant diet x genotype interaction with significantly greater decreases in TC ( p = 0.02) and apo B ( p = 0.006) among carriers of E4 when SFA was replaced with low GI carbohydrate on a lower fat diet (TC -0.28 mmol/L p = 0.03; apo B -0.1 g/L p = 0.02), and a relative increase in TC (in comparison to E3/E3) when SFA was replaced with MUFA and high GI carbohydrates (TC 0.3 mmol/L, p = 0.03). Among carriers of E2 (compared with E3/E3) there was an increase in triacylglycerol (TAG) when SFA was replaced with MUFA and low GI carbohydrates 0.46 mmol/L p = 0.001). There were no significant interactions between APOE genotype and diet for changes in indices of glucose homeostasis. In conclusion, variations in APOE genotype led to differential effects on the lipid response to the replacement of SFA with MUFA and low GI carbohydrates.

We aimed to determine whether altering dietary glycemic index (GI) in addition to healthy eating and weight loss advice affects arterial compliance and 24-hour blood pressure (BP), both coronary heart disease (CHD) risk factors. Middle-aged men with at least 1 CHD risk were randomized to a 6-month low-GI (LGI) or high-GI (HGI) diet. All were advised on healthy eating and weight loss. They were seen monthly to assess dietary compliance and anthropometrics. Carotid-femoral pulse wave velocity (PWV), fasting blood lipid profile, and glucose and insulin concentrations were measured at baseline and at months 3 and 6. Six-hour postprandial glucose and insulin responses and 24-hour ambulatory BP were also assessed at baseline and month 6. Thirty-eight subjects (HGI group, n = 16; LGI group, n = 22) completed the study. At month 6, groups differed in dietary GI, glycemic load, and carbohydrate intake (P < .001). Fasting insulin concentration and insulin resistance (calculated by homeostatic model assessment) were lower in the LGI than the HGI group (P < .01). The reduction in total cholesterol and 24-hour BP was bigger in the LGI than the HGI group (P < .05); and only the LGI group had significant reductions (P < .05) in PWV, low-density lipoprotein cholesterol, and triacylglycerol concentration. There were no differences in postprandial glucose or insulin responses between the groups. The results suggest that an LGI diet may be more beneficial in reducing CHD risk, including PWV and 24-hour BP, even in the setting of healthy eating and weight loss; and thus, further study is warranted.

Evidence suggests that a low-glycemic index (LGI) diet has a satiating effect and thus may enhance weight maintenance following weight loss. This study was conducted at Hammersmith Hospital, London, UK, and assessed the effect of altering diet GI on weight-loss maintenance. It consisted of a weight-loss phase and a 4-month randomized weight maintenance phase. Subjects were seen monthly to assess dietary compliance and anthropometrics. Appetite was assessed bimonthly by visual analogue scales while meal challenge postprandial insulin and glucose concentrations were assessed before and after the intervention. Following a median weight loss of 6.1 (interquartile range: 5.2-7.1) % body weight, subjects were randomized to a high-glycemic index (HGI) (n = 19) or LGI (n = 23) diet. Dietary composition differed only in GI (HGI group: 63.7 +/- 9.4; LGI group: 49.7 +/- 5.7, P < 0.001) and glycemic load (HGI group: 136.8 +/- 56.3; LGI group: 89.7 +/- 27.5, P < 0.001). Groups did not differ in body weight (weight change over 4 months, HGI group: 0.3 +/- 1.9 kg; LGI group: -0.7 +/- 2.9 kg, P = 0.3) or other anthropometric measurements. This pilot study suggests that in the setting of healthy eating, changing the diet GI does not appear to significantly affect weight maintenance.

Objective: To identify associations between dietary glycaemic index (GI) and weight, body mass index and other risk factors for cardiovascular disease (CVD) - waist-to-hip ratio (WHR), lipoprotein fractions, triacylglycerols (TAG) and blood pressure (BP) - in an older British population., Design: Cross-sectional dietary, anthropometric and biochemical data from the National Diet and Nutritional Survey for adults aged over 65 years were reanalysed using a hierarchical regression model. Associations between body weight, CVD risk factors, and dietary factors including GI and fibre intakes were explored among 1152 healthy older people living in the UK between 1994 and 1995., Results: In the unadjusted model, GI was significantly and directly associated with TAG (beta = 0.008 +/- 0.003) and diastolic BP (beta = 0.325 +/- 0.164) in males. These relationships were attenuated and non-significant after adjustment for potential confounding factors. WHR (beta = 0.003 +/- 0.001) and TAG (beta = 0.005 +/- 0.002) were significantly predicted by GI in males and females combined. The association with WHR was attenuated by adjustment for sex, age, region and social class; the relationship with TAG was non-significant after adjustment for other potential dietary confounders., Conclusion: After controlling for potential confounders, no clear links were detected between GI and body weight or other CVD risk factors. This study provides little evidence for advising the consumption of a low-GI diet in the elderly to prevent weight gain or improve other CVD risk factors.

Elevated postprandial glycaemia has been linked to CVD in a number of different epidemiological studies involving predominantly non-diabetic volunteers. The MiniMed continuous glucose monitor, which measures blood glucose every 5 min, over a 24 h period, was used to investigate changes in blood glucose readings before and after instigating a diet with low glycaemic index (GI) for 1 week in free-living healthy individuals. Nine healthy people (age 27 (SEM 1.3) years, BMI 23.7 (SEM 0.7) kg/m2, one male, eight females) completed the study. A reduction in GI (59.7 (SEM 2) v. 52.1 (SEM 2), P<0.01) occurred in all nine subjects while energy and other macronutrients remained constant. A significant reduction was also observed in fasting glucose at 06.00 hours (5.4 (SEM 0.2) v. 4.4 (SEM 0.3) mmol/l, P<0.001), mean glucose (5.6 (SEM 0.2) v. 5.1 (SEM 0.2) mmol/l, P=0.004), area under the 24 h glucose curve (8102 (SEM 243) v. 750 (SEM 235) mmol/l per min, P=0.004) and area under the overnight, 8 h glucose curve (2677 (SEM 92) v. 2223 (SEM 121) mmol/l per min, P=0.01). The present study provides important data on how a simple adjustment to the diet can improve glucose profiles that, if sustained in the long term, would be predicted from epidemiological studies to have a favourable influence on CVD.

Background Starchy foods can have a profound effect on metabolism. The structural properties of starchy foods can affect their digestibility and postprandial metabolic responses, which in the long term may be associated with the risk of type 2 diabetes and obesity. Objectives This systematic review sought to evaluate the clinical evidence regarding the impact of the microstructures within starchy foods on postprandial glucose and insulin responses alongside appetite regulation. Methods A systematic search was performed in the PUBMED, Ovid Medicine, EMBASE, and Google Scholar databases for data published up to 18 January 2021. Data were extracted by 3 independent reviewers from randomized crossover trials (RCTs) that investigated the effect of microstructural factors on postprandial glucose, insulin, appetite-regulating hormone responses, and subjective satiety scores in healthy participants. Results We identified 745 potential articles, and 25 RCTs (n  = 369 participants) met our inclusion criteria: 6 evaluated the amylose-to-amylopectin ratio, 6 evaluated the degree of starch gelatinization, 2 evaluated the degree of starch retrogradation, 1 studied starch–protein interactions, and 12 investigated cell and tissue structures. Meta-analyses showed that significant reductions in postprandial glucose and insulin levels was caused by starch with a high amylose content [standardized mean difference (SMD) = −0.64 mmol/L*min (95% CI: −0.83 to −0.46) and SMD = −0.81 pmol/L*min (95% CI: −1.07 to −0.55), respectively], less-gelatinized starch [SMD = −0.54 mmol/L*min (95% CI: −0.75 to −0.34) and SMD = −0.48 pmol/L*min (95% CI: −0.75 to −0.21), respectively], retrograded starch (for glucose incremental AUC; SMD = −0.46 pmol/L*min; 95% CI: −0.80 to −0.12), and intact and large particles [SMD = −0.43 mmol/L*min (95% CI: −0.58 to −0.28) and SMD = −0.63 pmol/L*min (95% CI: −0.86 to −0.40), respectively]. All analyses showed minor or moderate heterogeneity (I2 < 50%). Sufficient evidence was not found to suggest how these structural factors influence appetite. Conclusions The manipulation of microstructures in starchy food may be an effective way to improve postprandial glycemia and insulinemia in the healthy population. The protocol for this systematic review and meta-analysis was registered in the international prospective register of systematic reviews (PROSPERO) as CRD42020190873. [ABSTRACT FROM AUTHOR]

Presents a letter to the editor regarding how diets with a low glycemic index have been shown to improve glucose tolerance in clinical studies.

Abstract: Aims: Study the effect of several boluses of a new diabetes-specific formula (DSF) during the day on 24h glucose profile. Methods: In this randomized, controlled, double-blind, cross-over study 12 ambulatory type 2 diabetic patients were included. Subjects received a new DSF and an isocaloric standard fibre-containing formula (SF) while continuing their anti-diabetic medication. Subjects received 100% of their calculated daily energy requirements as bolus feeding every 3h (5 times/day, starting at 8.00a.m.±1h). Results: Glucose profiles were significantly better after administration of DSF compared with SF determined as mean glucose concentration (±SEM) (8.7±0.5 versus 9.6±0.6mmol/L, p <0.05 during 24h; 9.4±0.6 versus 10.7±0.6mmol/L, p <0.001 during daytime) or as incremental area under the curve during daytime (−44%; p <0.05). Subjects receiving DSF experienced less hyperglycaemic time over 24h (−26%; p <0.05) and during daytime (−30%; p <0.05). Furthermore, lower individual and mean (delta) peak glucose levels were found (p <0.05). No clinically relevant differences in gastrointestinal tolerance were observed. Conclusions: Using DSF resulted in significantly better 24h and postprandial glucose profiles than fibre-containing SF after bolus administration and may therefore help to improve glycaemic control in diabetic patients. [Copyright &y& Elsevier]