Effect of Wholegrain Flour Particle Size in Bread on Glycaemic and Insulinaemic Response Among People with Risk Factors for Type 2 Diabetes: A Randomised Crossover Trial

Wholegrain flour produced by roller-milling is predominantly comprised of fine particles, while stoneground flour tends to have a comparatively smaller proportion of fine particles. Differences in flour particle size distribution can affect postprandial glycaemia in people with type 2 diabetes and postprandial insulinaemia in people with and without type 2 diabetes. No prior studies have investigated the effect of wholegrain flour particle size distribution on glycaemic or insulinaemic response among people with impaired glucose tolerance or risk factors for type 2 diabetes. In a randomised crossover study, we tested the 180-min acute glycaemic and insulinaemic responses to three wholegrain breads differing in flour particle size and milling method: (1) fine roller-milled flour, (2) fine stoneground flour, and (3) coarse stoneground flour. Participants (n = 23) were males and females with risk factors for type 2 diabetes (age 55–75 y, BMI >28 kg/m2, completing less than 150 min moderate to vigorous intensity activity per week). Each test meal provided 50 g available carbohydrate, and test foods were matched for energy and macronutrients. There was no significant difference in blood glucose iAUC (incremental area under the curve) between the coarse stoneground flour bread and the fine stoneground flour bread (mean difference −20.8 (95% CI: −51.5, 10.0) mmol·min/L) and between the coarse stoneground flour bread and the fine roller-milled flour bread (mean difference −23.3 (95% CI: −57.6, 11.0) mmol·min/L). The mean difference in insulin iAUC for fine stoneground flour bread compared with the fine roller-milled flour bread was −6.9% (95% CI: −20.5%, 9.2%) and compared with the coarse stoneground flour bread was 9.9% (95% CI: −2.6%, 23.9%). There was no evidence of an effect of flour particle size on postprandial glycaemia and insulinaemia among older people with risk factors for type 2 diabetes, most of whom were normoglycaemic.

Effect of Acute Acai (Euterpe oleracea Mart.) Supplementation on Postprandial Glycaemia in Healthy Adults: A Pilot Randomised Controlled Study

Objectives Anthocyanin rich foods may ameliorate postprandial glycaemia. Postprandial glycaemia is associated with Type 2 Diabetes and a risk factor for cardiovascular disease. Acai berry is high in anthocyanins and has received attention for its health benefits. However, human trials are limited. The objective of the present study was to investigate the effect of acai berry extract on postprandial glycaemia responses in healthy adults. Methods Ten healthy participants, aged 18–65 years (mean 33 ± 16), with a body mass index (BMI) of 18.5–24.9 kg/m2 (mean 22.2 ± 1.5) completed a randomized, controlled, double-blind, crossover, acute dietary intervention trial. Participants consumed either an acai-based smoothie (AS) containing 150g acai pulp or a macronutrient-matched control placebo smoothie (PS). The primary endpoint was blood glucose concentration (BGC) which was determined by a capillary sampling method at baseline and at regular intervals up to 2 hours postprandially. Results Consumption of acai resulted in lower mean BGC compared to placebo (5.38 ± 0.46mmol/l vs. 5.40 ± 0.63mmol/l), but this was not significant (p = 0.888), even after controlling for age and BMI. There was no significant difference in BGC incremental area under the curve (iAUC) for acai relative to placebo. Conclusions In this acute study on heathy adults of a wide age range, acai consumption was not associated with improvements in postprandial glycaemia. Future long-term, adequately powered intervention studies, assessing additional biomarkers of disease risk are needed to fully elucidate the benefits of acai to health. Funding Sources None.

Gut-Based Strategies to Reduce Postprandial Glycaemia in Type 2 Diabetes

Postprandial glycemic control is an important target for optimal type 2 diabetes management, but is often difficult to achieve. The gastrointestinal tract plays a major role in modulating postprandial glycaemia in both health and diabetes. The various strategies that have been proposed to modulate gastrointestinal function, particularly by slowing gastric emptying and/or stimulating incretin hormone GLP-1, are summarized in this review.

Effects of intragastric administration of L-tryptophan on the glycaemic response to a nutrient drink in men with type 2 diabetes — impacts on gastric emptying, glucoregulatory hormones and glucose absorption

Background The rate of gastric emptying and glucoregulatory hormones are key determinants of postprandial glycaemia. Intragastric administration of L-tryptophan slows gastric emptying and reduces the glycaemic response to a nutrient drink in lean individuals and those with obesity. We investigated whether tryptophan decreases postprandial glycaemia and slows gastric emptying in type 2 diabetes (T2D). Methods Twelve men with T2D (age: 63 ± 2 years, HbA1c: 49.7 ± 2.5 mmol/mol, BMI: 30 ± 1 kg/m2) received, on three separate occasions, 3 g (‘Trp-3’) or 1.5 g (‘Trp-1.5’) tryptophan, or control (0.9% saline), intragastrically, in randomised, double-blind fashion, 30 min before a mixed-nutrient drink (500 kcal, 74 g carbohydrates), containing 3 g 3-O-methyl-D-glucose (3-OMG) to assess glucose absorption. Venous blood samples were obtained at baseline, after tryptophan, and for 2 h post-drink for measurements of plasma glucose, C-peptide, glucagon and 3-OMG. Gastric emptying of the drink was quantified using two-dimensional ultrasound. Results Tryptophan alone stimulated C-peptide (P = 0.002) and glucagon (P = 0.04), but did not affect fasting glucose. In response to the drink, Trp-3 lowered plasma glucose from t = 15–30 min and from t = 30–45 min compared with control and Trp-1.5, respectively (both P < 0.05), with no differences in peak glucose between treatments. Gastric emptying tended to be slower after Trp-3, but not Trp-1.5, than control (P = 0.06). Plasma C-peptide, glucagon and 3-OMG increased on all days, with no major differences between treatments. Conclusions In people with T2D, intragastric administration of 3 g tryptophan modestly slows gastric emptying, associated with a delayed rise, but not an overall lowering of, postprandial glucose.

Food order and glucose excursion in Indian adults with normal and overweight/obese Body Mass Index: A randomised crossover pilot trial

Background: Postprandial glycaemia has an impact on health but there is limited data about the effect of food order on postprandial glycaemia by body weight status. Aim: To investigate the effects of food order on postprandial glucose (PPG) excursion, in Indian adults with normal (NL) and overweight/obese (OW) Body Mass Index. Methods: This randomised crossover study was conducted at a Malaysian university among Indian adults without diabetes. The participants consumed isocaloric test meals at three study visits based on randomised food orders: carbohydrate first/protein last (CF); protein first/carbohydrate last (CL); and a composite meal containing carbohydrate and protein (CM). Capillary blood glucose was measured at baseline, 30, 60, 90 and 120 minutes after starting the meal. Results: The CL food order had a blunting effect on PPG excursion at 30 and 60 minutes ( p < 0.01). The CL food order resulted in lower glucose peak when compared with the CF and CM food order ( p < 0.001). The CL food order resulted in lower incremental glucose peak (mmol/L) (NL: CF 3.9 ± 0.3, CM 3.0 ± 0.3, CL 2.0 ± 0.2; OW: CF 2.9 ± 0.3, CM 2.5 ± 0.3, CL 1.8 ± 0.2) and iAUC 0–120 min (mmol/Lxmin) (NL: CF 272.4 ± 26.7, CM 206.2 ± 30.3, CL 122.0 ± 14.8; OW: CF 193.2 ± 23.1, CM 160.1 ± 21.7, CL 113.6 ± 15.3) when compared with the CF food order ( p < 0.001). The effect of food order on postprandial excursion did not differ between the NL ( n = 14) and the OW ( n = 17) groups. Conclusion: In participants with normal and overweight/obese BMI, consuming food in the protein first/carbohydrate last order had the biggest effect in reducing PPG excursion.

Blackcurrant (Ribes nigrum) lowers sugar-induced postprandial glycaemia independently and in a product with fermented quinoa: a randomised crossover trial

Berries rich in anthocyanins have beneficial effects on postprandial glycaemia. We investigated whether blackcurrant (75 g in a portion) independently and in a product with fermented quinoa induced similar effects on the sugar-induced postprandial glucose metabolism as observed before with 150 g of blackcurrant. Twenty-six healthy subjects (twenty-two females and four males) consumed four test products after fasting overnight in a randomised, controlled crossover design. Each test product portion contained 31 g of available carbohydrates and had similar composition of sugar components: 300 ml water with sucrose, glucose and fructose (SW; reference), blackcurrant purée with added sugars (BC), a product consisting of the blackcurrant purée and a product base with fermented quinoa (BCP) and the product base without blackcurrant (PB). Blood samples were collected at 0, 15, 30, 45, 60, 90, 120 and 180 min after eating each test product to analyse the concentrations of glucose, insulin and NEFA. In comparison with the SW, the intake of both the BC and BCP resulted in reduced glucose and insulin concentrations during the first 30 min, a more balanced decline during the first hour and improved glycaemic profile. The BCP induced more efficient effects than the BC due to the product base with fermented quinoa. A rebound of NEFA after the sugar-induced hypoglycaemic response was attenuated at the late postprandial phase by the BC and BCP. In conclusion, we showed that 75 g of blackcurrant and the product with fermented quinoa were able to lower postprandial glycaemia and insulinaemia.

Effect of chia seeds (Salvia hispanica) on postprandial glycaemia, body weight and hematological parameters in rats fed a high fat and fructose diet

Chia seeds (Salvia hispanica) are currently consumed by varied populations as superfoods due to their protective, functional and antioxidant properties. The aim of this study was to determine the effect of ground chia seeds/extracts on postprandial glycaemia, body weight, hematological parameters and cellular morphology in rats. Twenty male Wistar rats were assigned into three experimental groups and a control (n =5). Each experimental group received 10 g/20 g fructose/lard. Additionally, 90 g rat pellet was fed to group 1 and 3 which was supplemented with 20 g chia seed extract, group 2 received ground chia seeds only. Control group received 90 g rat pellet only for 28 days. The results on body weight changes indicated a gradual increase in body weight of chia seeds/extract fed rats as compared to fructose/lard group. There was an increase in postprandial blood glucose levels in group 1 from week I to IV contrary to groups supplemented with chia seeds/extract. Complete blood counts showed a significant increase (p = 0.008) in mean corpuscular hemoglobin concentration, basophils (p = 0.035), platelets (p = 0.025) and red cell distribution width (p = 0.008) in experimental groups compared to control. These results pinpoint the benefits of chia seeds.Keywords: Blood composition, functional food, glucose concentration, metabolic diseases, omega-3 fatty acids