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Context Sustained hyperglycemia triggers chronic disease, including type 2 diabetes. A considerable volume of research has explored the effects of brown seaweed on plasma glucose control, but equivocal findings have been reported. Objective A systematic review and meta-analysis was conducted to assess the evidence from human randomized controlled trials (RCTs) on the effects of brown seaweed on plasma glucose in healthy, at-risk, and individuals with type 2 diabetes. Data Sources MEDLINE/PubMed, EMBASE, and the Cochrane Library were searched for reports published between 2000 and 2020. Data Extraction Population, intervention, comparator, outcome, and study design data were extracted. Data Analysis Eighteen RCTs met our inclusion criteria. The reported results varied across and between populations. Meta-analyses showed a significant effect, favoring the intervention group for both fasting (mean difference –4.6 [95% CI –7.88, –1.33]) and postprandial (mean difference –7.1 [95% CI –7.4, –6.9]) plasma glucose. Conclusion Brown seaweed and its extracts show potential for preventing and managing hyperglycemia. Our meta-analysis confirms that brown seaweed positively affects plasma glucose homeostasis, with particularly promising postprandial plasma glucose effects. However, further research is needed because no high-quality RCT was identified. Species-specific and dose–response research is also required. Systematic Review Registration PROSPERO registration no. CRD42020187849.

Scope Green leafy vegetables (GLV) may improve postprandial glycaemic responses (PGR) and metabolic health. However, inter-individual variations (IIV) preclude conclusive evidence. Sirtuin system is emerging as a key player in blood glucose control. This study investigated IIV in PGR in women co-ingesting GLV with a carbohydrate meal and interactions with the sirtuin system. Methods and results Volunteers (n = 31 women) consumed rice, rice with bok choy or spinach (75g available carbohydrate) on separate occasions. Postprandial glucose, insulin, adropin and lipid levels were measured. Anthropometric measurements and sex hormones were measured. GeXP assay measured whole blood postprandial gene expression profiles of 25 markers involved in sirtuin signalling. GLV consumption had no significant effect on PGR which showed high variation. PGR correlated with age, but no other consistent associations were observed. Sirtuin gene expression profiles revealed distinct stratified subgroups associated with PGR, lipid, insulin, fat mass, waist/hip circumferences and adropin levels. Conclusion PGR to co-ingesting GLV with a carbohydrate meal were highly variable in this cohort and failed to reveal a significant reduction in PGR. Variable responses were largely independent of menopausal status and meal consumed. However, lower expression of sirtuin gene targets was associated with higher PGR and with markers linked to health status. This article is protected by copyright. All rights reserved.

Green tea catechins are potent inhibitors of enzymes for carbohydrate digestion. However, the potential of developing low glycaemic index bakery food using green tea extract has not been investigated. Results of this study showed that addition of green tea extract (GTE) at 0.45%, 1%, and 2% concentration levels significantly reduced the glycaemic potential of baked and steamed bread. The average retention levels of catechins in the baked and steamed bread were 75.3-89.5% and 81.4-99.3%, respectively. Bread fortified with 2% GTE showed a significantly lower level of glucose release during the first 90 min of pancreatic digestion as well as a lower content of rapidly digested starch (RDS) content. A significantly negative correlation was found between the catechin retention level and the RDS content of bread. The potential of transforming bread into a low GI food using GTE fortification was proven to be promising.

The glycemic response (GR) to food is influenced by both intrinsic and extrinsic factors. A consistent observation in GR studies is the wide within- and between-individual variations. The authors hypothesize that between-individual variations in the GR, insulin response (IR) and gastric emptying occur even when food particle size is standardized. Volunteers were tested on 2 nonconsecutive days after an overnight fast in randomized order. On 1 day, the volunteers consumed large (>2000 μm) rice particles, and on the second day, small rice particles (500-1000 μm). Subsequently, gastric emptying using the sodium [(13)C] acetate breath test (for 240 minutes) and GR and IR (for 120 minutes) from finger-prick blood samples were measured. The incremental area under the curve (IAUC) for the GR for small particles varied 45% more compared with whole rice. The small particles elicited a significantly greater GR IAUC than the large particles. The standard deviations associated with the IR IAUC for the small particles was 140% greater than that of the large particles. The total IAUC for IR was also significantly greater for the small particles than the large particles. The between-individual variations associated with gastric emptying times were similar for both samples. The gastric emptying latency phase, lag, and half time were significantly shorter for the small particles. Ingesting small particles causes faster gastric emptying and produces greater glycemic and IRs. Between-individual variations in GR and IR can be observed even when all the food associated factors including ingested particle size (mastication) are controlled for in humans.

The degree of mastication varies significantly between individuals and may be a cause for the considerable interindividual variation observed in the glycemic response (GR) to a single food. Using rice as the model, the aim of this study was to determine if interindividual differences in mastication and resulting degree of particle breakdown affected in vitro and in vivo glycemic potency. In a randomized crossover design, using 15 subjects, the particle size distribution and in vitro digestibility of individuals' chewed rice were determined along with their in vivo blood GR. The rapidly digested starch (RDS) content in the masticated boluses, moreover, was measured during in vitro digestion. The particle size distribution of masticated rice differed significantly interindividually. In vitro digestion of rice decreased as particle size increased. The degree of particle size breakdown as a result of mastication correlated with the RDS content in the chewed food bolus and initial digestion rate in vitro. The quantity of undigested material remaining at the end of 120-minute in vitro digestion correlated significantly with the percentage of particles greater than 2000 microm in masticated rice. The percentage of particles smaller than 500 microm correlated significantly with in vivo GR at 30 minutes postingestion but not with the total incremental area under the blood glucose curve. The degree of habitual mastication may therefore potentially influence both the magnitude and pattern of the GR and may partly explain interindividual differences in it. Although the study sets the base for future research, firm conclusions can be reached only upon the completion of additional work.

The objective of the present study was to determine the glycaemic index (GI) and glycaemic load (GL) values of standard portion sizes of Southeast Asian traditional foods. A total of fifteen popular Southeast Asian foods were evaluated. Of these foods, three were soft drinks, while the other twelve were solid foods commonly consumed in this region. In total, forty-seven healthy participants (eighteen males and twenty-nine females) volunteered to consume either glucose at least twice or one of the fifteen test foods after a 10–12 h overnight fast. Blood glucose concentrations were analysed before consumption of the test food, and 15, 30, 45, 60, 90 and 120 min after food consumption, using capillary blood samples. The GI value of each test food was calculated by expressing the incremental area under the blood glucose response curve (IAUC) value of the test food as a percentage of each participant's average IAUC value, with glucose as the reference food. Among the fifteen foods tested, six belonged to low-GI foods (Ice Green Tea, Beehoon, Pandan Waffle, Curry Puff, Youtiao and Kaya Butter Toast), three belonged to medium-GI foods (Barley Drink, Char Siew Pau and Nasi Lemak), and the other six belonged to high-GI foods (Ice Lemon Tea, Chinese Carrot Cake, Chinese Yam Cake, Chee Cheong Fun, Lo Mai Gai and Pink Rice Cake). The GI and GL values of these traditional foods provide valuable information to consumers, researchers and dietitians on the optimal food choice for glycaemic control. Moreover, our dataset provides GI values of fifteen foods that were not previously tested extensively, and it presents values of foods commonly consumed in Southeast Asia.

Limited research exists on how different oil types and time of addition affect starch digestibility of rice. This study aimed to assess the starch digestibility of white and red rice prepared with 2 oil types: vegetable oil (unsaturated fat) and ghee (clarified butter, saturated fat) added at 3 different time points during the cooking process ("before": frying raw rice in oil before boiling, "during": adding oil during boiling, and "after": stir-frying cooked rice in oil). Red rice produced a slower digestion rate than white rice. White rice digestibility was not affected by oil type, but was affected by addition time of oil. Adding oil "after" (stir-frying) to white or red rice resulted in higher slowly digestible starch. Red rice cooked using ghee showed the lowest amount of glucose release during in vitro digestion. The addition of ghee "during" (that is boiling with ghee) or "before" (that is frying rice raw with ghee then boiling) cooking showed potential for attenuating the postprandial glycemic response and increasing resistant starch content. This is the first report to show healthier ways of preparing rice. White rice with oil added "after" (stir-fried) may provide a source of sustained glucose and stabilize blood glucose levels. Boiling red rice with ghee or cooking red rice with ghee pilaf-style may provide beneficial effects on postprandial blood glucose and insulin concentrations, and improve colonic health. The encouraging results of the present study justify extending it to an in vivo investigation to conclusively determine the effect of time of addition of fat when rice is cooked on blood glucose homeostasis.Rice is a predominant source of energy in most of Asia with excessive consumption of rice being implicated in the rise of type 2 diabetes. Stir-frying white rice can be a source of sustained glucose and provide a stabilizing effect on blood glucose levels. Boiling red rice with ghee or cooking red rice with ghee pilaf-style may provide beneficial effects on postprandial blood glucose and insulin concentrations. This suggests how a single technique of adding fat in the cooking of rice at certain time points may be a useful method in providing taste and lowering glycemia.

Singapore is an island state that is composed of three major ethnic groups, namely Chinese, Malay and Indian. Its inhabitants consume food either using chopsticks (Chinese), fingers (Malay and Indian) or spoon (Chinese, Malay and Indian). Previous work by our group showed that the degree of mastication significantly influenced the glycemic response. The degree of mastication in turn may depend on the eating method as the amount of food taken per mouthful and chewing time differs between eating methods. Eleven healthy volunteers came in on six non-consecutive days to the laboratory and evaluated three methods of eating white rice (spoon, chopsticks and fingers) once and the reference food (glucose solution) three times in a random order. Their glycemic response (GR) was measured for the subsequent 120 min. Mastication parameters were determined using surface electrode electromyography. The GR to white rice eating with chopsticks was significantly lower than spoon. The GI of eating rice with chopsticks was 68 which is significantly lower than eating with spoon (GI=81). However there were no differences between fingers and spoon, and between fingers and chopsticks either in GR 120 min or GI. The inter-individual number of mouthful, number of chews per mouthful, chewing time per mouthful and the total time taken to consume the whole portion of rice were significantly different between spoon and chopsticks groups. Significant correlations between the number of mouthful to take the entire portion of rice and amount of rice per mouthful during mastication and the GR were observed for eating rice with spoon and chopsticks, but not for fingers. The results suggest that individual differences in number of mouthful and amount of rice per mouthful may be two of the causes for inter-individual differences in the GR between spoon and chopsticks. The present study suggests that eating rice with different feeding tools has different chewing times and amount of food taken per mouthful and then alters the GI of the rice.

White rice is the main staple for the majority in the world. The effects of protein, fat and vegetables on the glycaemic and insulinaemic responses to a white rice-based meal have not been reported. The aim of this study was to determine the effect of co-ingesting a high-protein food (breast chicken), a fat (ground nut oil), a leafy vegetable or all three on the glycaemic and insulinaemic responses of white rice in healthy adults.This was a randomized crossover trial conducted at the Clinical Nutrition Research Centre in Singapore. Twelve healthy volunteers were given five test meals (white rice alone, white rice with chicken, white rice with oil, white rice with vegetable and white rice with chicken, oil and vegetable) once and the reference food (glucose solution) three times in a random order at 1-week intervals. Capillary blood samples were then drawn serially for 3 h, and glucose and insulin were analysed.The glycaemic response (GR) to white rice with chicken breast, ground nut oil and vegetable was significantly lower than to white rice alone. The glycaemic index (GI) of pure white rice was 96, whereas combined with chicken breast, ground nut oil and vegetable, it was 50. The addition of oil delayed the peak glucose response and reduced the iAUC, resulting in a GI value of 67. The addition of chicken and vegetable resulted in a GI value of 73 and 82, respectively. The insulinaemic index (II) of the white rice-based meals varied between 54 and 89. Chicken breast in the meal increased the insulinaemic response and decreased the GR. White rice II was lower than the glucose control, which indicated that the former was not as insulinogenic as the latter. White rice with vegetable had the lowest II.Co-ingesting chicken, oil or vegetable with white rice considerably influences its glycaemic and insulinaemic responses. Co-ingesting white rice with all three components attenuates the GR to a greater degree than when it is eaten with any single one of them, and that this is not at the cost of an increased demand for insulin.

Dietary proteins are essential for the life of all animals and humans at all stages of the life cycle. They serve many structural and biochemical functions and have significant effects on health and wellbeing. Dietary protein consumption has shown an upward trend in developed countries in the past two decades primarily due to greater supply and affordability. Consumption is also on the rise in developing countries as affluence is increasing. Research shows that proteins have a notable impact on glucose homeostasis mechanisms, predominantly through their effects on insulin, incretins, gluconeogenesis, and gastric emptying. Since higher protein consumption and impaired glucose tolerance can be commonly seen in the same population demographics, a thorough understanding of the former's role in glucose homeostasis is crucial both toward the prevention and management of the latter. This chapter reviews the current state of the art on proteins, amino acids, and their effects on blood glucose and insulin secretion.

It is speculated that the physical form (liquid or solid) of the food substrate has an independent effect on the body's satiety mechanisms. Using a balanced and controlled design, the objective of the present study was to determine the glycemic response (GR), insulin response (IR) and subjective feelings of satiety to two solid (rice [BR] and spaghetti) and two liquid (orange juice and a sugar-sweetened fruit drink [SSD]) foods. Ten healthy participants consumed volume (576 ml) and carbohydrate (50 g) matched portions of the above test foods following a 12-h fast. Blood samples were obtained for the ensuing 120 min for glucose and insulin determination. The subjects also completed visual analog scales (VAS) providing data on subjective feelings of hunger, fullness and satiety. Although there were some significant differences in the total incremental areas under the curve for the GR and IR to liquids and solids, there were notable distinctions in the pattern of the response curves. The BR and SSD elicited significantly different levels of subjective hunger, fullness and satiety. The VAS ratings for all four treatments were at or below baseline by 30 min post-consumption. There were no associations between the GR/IR and VAS ratings. Although the GR and IR were not different between liquids and solids, their differential response patterns could have an impact on satiety and merits further investigation.

Objective The postprandial glycemic response and glycemic index (GI) of spaghetti made with semolina and the addition of two β-glucan barley concentrates, Glucagel (GG) and Barley Balance (BB), was studied. Methods For each type of β-glucan concentrate, six spaghetti samples containing increasing percentages (0%, 2%, 4%, 6%, 8%, and 10%) of β-glucan were made. Nine healthy subjects were recruited for measuring the glycemic response and GI. Subjects were served portions of the test foods (50 g of available carbohydrates) and a reference food (50 g of glucose) on separate occasions. Capillary blood glucose was measured up to 120 min after consuming the spaghetti. The total glycemic response was calculated geometrically as the incremental areas under the curve (IAUC) using the trapezoid rule. The GI was calculated geometrically by expressing the IAUC for the test food as a percentage of each subject’s average IAUC for the glucose. Results The IAUC for spaghetti with and without β-glucan was significantly less compared with glucose. The GG spaghetti had IAUC values similar to the spaghetti without β-glucan concentrate. The BB spaghetti showed IAUC values lower than that of the spaghetti without β-glucan. In particular, the spaghetti with 10% BB had an IAUC 52% lower ( P ≤ 0.017) than the spaghetti with β-glucan. The GI values for spaghetti with GG were statistically similar to the control. The GI of BB spaghetti decreased with increasing BB concentrations. In particular, the GI of 10% BB spaghetti was 54% lower ( P ≤0.02; GI = 29) than that of the control (GI = 64). Conclusion The BB concentrate significantly decreases the IAUC and GI of spaghetti at a dose of 10%. GI at the same concentrations does not.