The effect of fruit consumption time on glucose regulation in pregnancy with gestational diabetes / O efeito do tempo de consumo de fruta na regulação da glicose na gravidez com diabetes gestacional

ABSTRACT Objective This study aims to determine the effect of fruit consumption time on blood glucose regulation in pregnant women with gestational diabetes. Methods The study was carried out with 64 volunteer participants diagnosed with gestational diabetes. Participants who were directed to the Department of Nutrition and Dietetics were divided into two groups according to the order of application; Group 1 was included in the nutrition treatment program for a week, consuming fruit for the main meal and Group 2 for the snack. During this process, the participants were applied a personalized nutrition plan that was adjusted equally for macronutrients of all meals containing isocaloric 3 main and 4 snacks. In this process, blood glucose values were measured six times a day by the participants and the blood glucose results of both groups before starting the nutrition therapy and on the seventh day after starting the medical nutrition therapy were compared. Results The mean age of the women participating in the study was 33.50±4.95 years and 32.28±5.18 years for the 1st and 2nd groups, respectively, and the groups were similar in terms of anthropometric measurements. The post-diet average of postprandial blood glucose levels in the morning within each group dropped from 180mg/d to 115mg/dL (p<0,001) for Group 1 and from 185mg/dL to 110mg/dL (p<0,001) for Group 2. There was a decrease in the fasting plasma glucose and postprandial blood glucose levels measured in the morning, noon and evening before and after the medical nutrition therapy of the groups, but no statistically significant difference was found between the groups (p>0.05). All participants on the gestational diabetes diet had normal blood sugar levels without the need for insulin. A statistically significant decrease was observed in the postprandial blood glucose-fasting plasma glucose difference levels of the pregnant women in the group that consumed fruit for snacks (Group 2) on the seventh day of the study (p<0,001). There was no significant difference in the pre-diet and post-diet morning fasting plasma glucose values of both groups (p>0,05). Conclusion This study found that medical nutrition therapy in pregnant women with gestational diabetes led to a decrease in blood glucose levels, but consuming fruits as a snack or at the main meal did not make a significant difference on fasting plasma glucose and postprandial blood glucose. It was concluded that the type and amount of carbohydrates consumed daily in gestational diabetes are determinative on blood glucose level.

RESUMO Objetivo O objetivo deste estudo é determinar o efeito do tempo de consumo de fruta na regulação da glucose no sangue em mulheres grávidas com diabetes gestacional. Métodos Este estudo foi realizado com 64 participantes voluntários diagnosticados com diabetes gestacional. Os participantes que foram encaminhados para o Departamento de Nutrição e Dietética foram divididos em dois grupos, de acordo com a ordem da sua aplicação. O grupo 1 foi incluído no programa de tratamento médico nutricional durante uma semana, consumindo fruta para a refeição principal e o grupo 2 para os lanches. Neste processo, foi aplicado aos participantes um plano de nutrição personalizado, com isocalórico, 3 refeições principais e 4 lanches, os macronutrientes de todas as refeições foram ajustados igualmente. Neste processo, os valores de glicemia foram medidos seis vezes por dia pelos participantes, e foram comparados os resultados da glicemia de ambos os grupos antes de se iniciar a terapia nutricional médica e no sétimo dia após o início da terapia nutricional médica. Resultados A idade média das mulheres que participaram no estudo foi de 33,50±4,95 e 32,28±5,18 anos para o 1º e 2º grupos, respetivamente, e não houve diferença entre os grupos em termos de medidas antropométricas. A glicemia média pós-prandial de manhã após terapia nutricional médica dentro dos grupos variou entre 180mg/d a 115mg/dL (p<0,001) para o Grupo 1, e de 185mg/dL a 110mg/dL para o Grupo 2 (p<0,001). Houve uma diminuição nos níveis de glicemia em jejum e glicemia média pós-prandial medidos de manhã, meio-dia e noite antes e depois da terapia nutricional médica dos grupos, mas não houve diferença estatisticamente significativa entre os grupos (p>0,05). Os níveis de açúcar no sangue de todos os participantes na dieta diabetes gestacional baixaram para níveis normais sem necessidade de terapia com insulina. Uma diminuição estatisticamente significativa foi observada no sétimo dia do estudo nos níveis de diferença do glicemia média pós-prandial-glicemia em jejum das mulheres grávidas do grupo que consumiram fruta como aperitivo (Grupo 2). (p<0.001). Não houve diferença significativa nos valores de glicemia em jejum matinal de ambos os grupos antes e depois da dieta (p>0,05). Conclusão Como resultado deste estudo, verificou-se que a terapia nutricional levou a uma diminuição do açúcar no sangue em mulheres grávidas com diabetes gestacional, mas o consumo de fruta como lanche ou refeição principal não fez uma diferença significativa no jejum e na glucose do sangue pós-prandial. Concluiu-se que o tipo e a quantidade de hidratos de carbono consumidos diariamente na diabetes gestacional são determinantes para o nível de glicose no sangue.

Postprandial Dried Blood Spot-Based Nutritional Metabolomic Analysis Discriminates a High-Fat, High-Protein Meat-Based Diet from a High Carbohydrate Vegan Diet: A Randomized Controlled Crossover Trial.

BACKGROUND: Due to the challenges associated with accurate monitoring of dietary intake in humans, nutritional metabolomics (including food intake biomarkers) analysis as a complementary tool to traditional dietary assessment methods has been explored. Food intake biomarker assessment using postprandial dried blood spot (DBS) collection can be a convenient and accurate means of monitoring dietary intake vs 24-hour urine collection. OBJECTIVE: The objective of this study was to use nutritional metabolomics analysis to differentiate a high-fat, high-protein meat (HFPM) diet from a high-carbohydrate vegan (HCV) diet in postprandial DBS and 24-hour urine. DESIGN: This was a randomized controlled crossover feeding trial. PARTICIPANTS/SETTING: Participants were healthy young adult volunteers (n = 8) in California. The study was completed in August 2019. INTERVENTION: The standardized isocaloric diet interventions included an HFPM and an HCV diet. Participants attended 2 intervention days, separated by a 2-week washout. MAIN OUTCOME MEASURES: During each intervention day, a finger-prick blood sample was collected in the fasting state, 3 hours post breakfast, and 3 hours post lunch. Participants also collected their urine for 24 hours. DBS and urine samples were analyzed by ultra-performance liquid chromatography mass spectrometry to identify potential food intake biomarkers. STATISTICAL ANALYSES PERFORMED: Principal component analysis for discriminatory analysis and univariate analysis using paired t tests were performed. RESULTS: Principal component analysis found no discrimination of baseline DBS samples. In both the postprandial DBS and 24-hour urine, post-HFPM consumption had higher (P < 0.05) levels of acylcarnitines, creatine, and cis-trans hydroxyproline, and the HCV diet was associated with elevated sorbitol (P < 0.05). The HFPM diet had higher concentrations of triacylglycerols with fewer than 54 total carbons in DBS, and 24-hour urine had higher nucleoside mono- and di-phosphates (P < 0.05). CONCLUSIONS: Nutritional metabolomics profiles of postprandial DBS and 24-hour urine collections were capable of differentiating the HFPM and HCV diets. The potential use of postprandial DBS-based metabolomic analysis deserves further investigation for dietary intake monitoring.

Addition of Caffeine to a Carbohydrate Feeding Strategy Prior to Intermittent Exercise.

The ergogenic effect of caffeine is well established, although no investigations providing a high carbohydrate feeding strategy (pre-exercise meal=2 g/kg BM) co-ingested with caffeine exist for soccer. This investigation examines the effect of caffeine in addition to a pre-exercise carbohydrate meal and drink mid-way through a soccer simulation. Eight recreational soccer players completed an 85-minute soccer simulation followed by an exercise capacity test (Yo-yo Intermittent Endurance test level 2) on two occasions. Prior to exercise participants consumed a high carbohydrate meal, with placebo or 5 mg/kg BM-1 caffeine. No significant performance effect was identified (p=0.099) despite a 12.8% (109 m) improvement in exercise capacity following caffeine. Rates of carbohydrate and fat oxidation did not differ between conditions and nor were differences apparent for plasma glucose, fatty acids, glycerol, ß-hydroxybutyrate (p>0.05). However, an increase in lactate was observed for caffeine (p=0.039). A significant condition effect on rating of perceived exertion was identified (p<0.001), with the overall mean for the protocol lowered to 11.7±0.9 au for caffeine compared to 12.8±1.3 au. Caffeine supplementation with a carbohydrate feeding strategy failed to affect metabolic and metabolite responses, although reductions in perception of exercise were observed. While a 12.8% increase in exercise capacity was noted the findings were not significant, possibly due to the small sample size.

Carbohydrate Replacement of Rice or Potato with Lentils Reduces the Postprandial Glycemic Response in Healthy Adults in an Acute, Randomized, Crossover Trial.

Background: The postprandial blood glucose response (PBGR) following carbohydrate replacement of high-glycemic index (GI) foods with pulses, in a mixed meal, has not been accurately defined. Objective: We aimed to determine the extent to which PBGR and relative glycemic response (RGR) are lowered when half of the available carbohydrate (AC) from rice or potato is replaced with cooked lentils. Methods: Using a crossover design, 2 groups of 24 healthy adults randomly consumed 50 g AC from control white rice alone [mean ± SD body mass index (BMI, in kg/m2): 24.3 ± 0.5; mean ± SD age: 27.7 ± 1.2 y], instant potato alone (BMI: 24.0 ± 0.5; age: 27.4 ± 1.2 y), or the same starch source in a 50:50 AC combination with each of 3 types of commercially available lentils (large green, small green, split red). Fasting and postprandial blood samples were analyzed for glucose and insulin, and used to derive incremental area under the curve (iAUC), RGR, and maximum concentration (Cmax). Treatment effects were assessed with the use of repeated-measures ANOVA within the rice and potato treatments. Results: In comparison to rice alone, blood glucose iAUC and Cmax (P < 0.001) were lowered after consumption of rice with large green (P = 0.057), small green (P = 0.002), and split red (P = 0.006) lentils. Blood glucose iAUC and Cmax were also significantly lowered (P < 0.0001) after consumption of potato combined with each lentil, compared to potato alone. Plasma insulin iAUC and Cmax were significantly (P < 0.001) decreased when lentils were combined with potato, but not with rice. The RGRs of rice and potato were lowered by ∼20% and 35%, respectively, when half of their AC was replaced with lentils. Conclusions: Replacing half of the AC from high-GI foods with lentils significantly attenuates PBGR in healthy adults; this can contribute to defining a health claim for pulses and blood glucose lowering. This trial was registered at clinicaltrials.gov as NCT02426606.

Changes in dietary glycemic index and glycemic load in Australian adults from 1995 to 2012.

Background: Australians have used the glycemic index (GI) since 1995; however, there are no data on changes in carbohydrate quality over time.Objectives: The aim was to compare average dietary GI and glycemic load (GL), and contributing carbohydrate foods, in the 2 most recent national dietary surveys.Design: Dietary data from adult participants of national nutrition surveys conducted in 1995 (the 1995 Australian National Nutrition Survey; n = 8703) and 2012 (the 2011-2012 National Nutrition and Physical Activity Survey; n = 6278), collected by a single 24-h recall, were analyzed. The differences in mean dietary GI and GL between surveys were compared by using 1-factor ANOVA. The main sources of dietary GL in the 2 surveys were also assessed. Multiple linear regression was performed to examine the contributions of the food groups to interindividual variations in dietary GI and GL.Results: Overall, dietary GI and GL decreased by 5% and 12%, respectively, from 1995 to 2012 (GI on glucose standard: 56.5 ± 6.2 compared with 53.9 ± 6.8, respectively; GL: 153.3 ± 62.1 compared with 135.4 ± 58.5, respectively; both P < 0.001). Breads were the main contributor to GL at both time points. Potatoes and sweetened beverages contributed less, whereas cereal-based dishes contributed more in 2012 than in 1995. The top 20 GL-contributing food groups explained less interindividual variation in dietary GI (R2: 0.376 compared with 0.290) and GL (R2: 0.825 compared with 0.770) in 2012 than in 1995.Conclusion: Although the average dietary GI and GL declined between 1995 and 2012, trends in specific carbohydrate foods suggest that Australians are avoiding potatoes and sugary beverages in favor of a greater variety of carbohydrate foods, particularly cereal products.

Inhibition of the glycaemic response by onion: a comparison between lactose-tolerant and lactose-intolerant adults.

This pilot study compared inhibition of the glycaemic response to glucose by a dietary source of quercetin glucosides (onion) in lactose-tolerant adults (n=12) and lactose-intolerant adults (n=12). We hypothesised that lactose-intolerant people (who do not express lactase) will retain intact quercetin glucosides that can inhibit glucose uptake via the glucose transporter SGLT1, whereas lactose-tolerant people (who do express lactase) will hydrolyse quercetin glucosides to free quercetin that does not inhibit glucose uptake. In a glucose tolerance test, reduction in peak glucose levels by an onion meal was higher in lactose-intolerant people than in lactose-tolerant people (44.2 versus 19.3%, P=0.04). Incremental area under the blood glucose curve was reduced more in lactose-intolerant people, but was not statistically significant (54.5 versus 42.1%, P=0.42). A diet containing quercetin glucosides may be of greater benefit for glycaemic control in lactose-intolerant people than in lactose-tolerant people.

Physiological and performance effects of carbohydrate gels consumed prior to the extra-time period of prolonged simulated soccer match-play.

OBJECTIVES: The physiological and performance effects of carbohydrate-electrolyte gels consumed before the 30min extra-time period of prolonged soccer-specific exercise were investigated. DESIGN: Randomised, double-blind, crossover. METHODS: Eight English Premier League academy soccer players performed 120min of soccer-specific exercise on two occasions while consuming fluid-electrolyte beverages before exercise, at half-time and 90min. Carbohydrate-electrolyte (0.7±0.1gkg(-1) BM) or energy-free placebo gels were consumed ∼5min before extra-time. Blood samples were taken before exercise, at half-time and every 15min during exercise. Physical (15-m and 30-m sprint speed, 30-m sprint maintenance and countermovement jump height) and technical (soccer dribbling) performance was assessed throughout each trial. RESULTS: Carbohydrate-electrolyte gels improved dribbling precision (+29±20%) and raised blood glucose concentrations by 0.7±0.8mmoll(-1) during extra-time (both p<0.01). Supplementation did not affect sprint velocities (15m and 30m), 30-m sprint maintenance or dribbling speed as reductions compared to 0-15min values occurred at 105-120min irrespective of trial (all p<0.05). Plasma osmolality and blood sodium concentrations increased post-exercise vs. the opening 15min (p<0.05) but no effect of supplementation existed. Selected markers of physical performance (jump height, 30-m sprint velocity and 30-m repeated sprint maintenance) also reduced by >3% during half-time (all p<0.05). CONCLUSIONS: Carbohydrate-electrolyte gel ingestion raised blood glucose concentrations and improved dribbling performance during the extra-time period of simulated soccer match-play. Supplementation did not attenuate reductions in physical performance and hydration status that occurred during extra-time.

The acute effects of green tea and carbohydrate coingestion on systemic inflammation and oxidative stress during sprint cycling.

Green tea (Camellia sinensis) has anti-oxidative and anti-inflammatory effects, which may be beneficial to athletes performing high-intensity exercise. This study investigated the effects of carbohydrate and green tea coingestion on sprint cycling performance and associated oxidative stress and immunoendocrine responses to exercise. In a crossover design, 9 well-trained male cyclists completed 3 sets of 8 repetitions of 100-m uphill sprint cycling while ingesting green tea and carbohydrate (TEA) (22 mg/kg body mass catechins, 6 mg/kg body mass caffeine, 230 mg/kg glucose, and 110 mg/kg fructose) or carbohydrate only (CHO) (230 mg/kg body mass glucose and 110 mg/kg body mass fructose) during each 10-min recovery period between sets. Blood samples were collected before exercise, 10 min after exercise, and 14 h after exercise. There was no effect of acute TEA ingestion on cycling sprint performance (p = 0.29), although TEA maintained postexercise testosterone and lymphocyte concentrations, which decreased significantly in the CHO group (p < 0.001). While there was a trend for lower postexercise neutrophil count with TEA (p = 0.05), there were no significant differences between TEA and CHO for circulating cytokines (p > 0.20), markers of oxidative stress and antioxidant capacity (p > 0.17), adiponectin concentration (p = 0.60), or muscle damage markers (p > 0.64). While acute green tea ingestion prevents the postexercise decrease in testosterone and lymphocytes, it does not appear to benefit cycling sprint performance or reduce markers of oxidation and inflammation when compared with carbohydrate alone.

Effects of supplementation with omega-3 on insulin sensitivity and non-esterified free fatty acid (NEFA) in type 2 diabetic patients.

OBJECTIVE: The aim of this study was to determine the role of omega-3 supplementation on NEFA concentration, insulin sensitivity and resistance, and glucose and lipid metabolism in type 2 diabetic patients. SUBJECTS AND METHODS: Forty-four type 2 diabetic patients were randomly recruited into two groups. Group A received 4 g/day omega-3 soft gels, and group B received a placebo for 10 wks. Blood samples were collected after 12-h fast. Physical activity records, three-day food records, and anthropometric measurements were obtained from all participants at the beginning and end of the study. RESULTS: Omega-3 supplementation caused a significant reduction in NEFA in the intervention group compared with the placebo group (P = 0.009). Additionally, the administration of omega-3 resulted in significantly greater changes (Diff) for the intervention group in various parameters, such as insulin and Quicki indices compared with the placebo group (P < 0.05). CONCLUSIONS: Omega-3 fatty acid supplementation in type 2 diabetic patients improved insulin sensitivity, probably due to the decrease in NEFA concentrations.

Effects of supplementation with omega-3 on insulin sensitivity and non-esterified free fatty acid (NEFA) in type 2 diabetic patients / Efeito da suplementação com ômega-3 sobre a sensibilidade à insulina e aos ácidos graxos livres não esterificados (AGNE) em pacientes com diabetes tipo 2

Objective: The aim of this study was to determine the role of omega-3 supplementation on NEFA concentration, insulin sensitivity and resistance, and glucose and lipid metabolism in type 2 diabetic patients. Subjects and methods: Forty-four type 2 diabetic patients were randomly recruited into two groups. Group A received 4 g/day omega-3 soft gels, and group B received a placebo for 10 wks. Blood samples were collected after 12-h fast. Physical activity records, three-day food records, and anthropometric measurements were obtained from all participants at the beginning and end of the study. Results: Omega-3 supplementation caused a significant reduction in NEFA in the intervention group compared with the placebo group (P = 0.009). Additionally, the administration of omega-3 resulted in significantly greater changes (Diff) for the intervention group in various parameters, such as insulin and Quicki indices compared with the placebo group (P < 0.05). Conclusions: Omega-3 fatty acid supplementation in type 2 diabetic patients improved insulin sensitivity, probably due to the decrease in NEFA concentrations. Arq Bras Endocrinol Metab. 2014;58(4):335-40 .

Objetivo: O objetivo deste estudo foi analisar o papel da suplementação com ácidos graxos ômega-3 sobre a concentração de ácidos graxos não esterificados (AGNE), resistência e sensibilidade à insulina e metabolismo de lipídios em pacientes com diabetes melito tipo 2. Sujeitos e métodos: Quarenta e quatro pacientes com diabetes tipo 2 foram recrutados aleatoriamente e alocados em um de dois grupos. O Grupo A recebeu 4 g/dia de ômega-3 na forma de cápsulas gelatinosas e o grupo B recebeu placebo durante 10 semanas. Amostras de sangue foram coletadas após 12 horas de jejum. Registros da atividade física, da dieta de três dias e medidas antropométricas foram obtidos de todos os participantes no início e no final do estudo. Resultados: A suplementação com ômega-3 causou uma redução significativa na AGNE em comparação com grupo placebo (P = 0,008). Além disso, a administração de ômega-3 resultou em alterações significativamente maiores (Dif) em vários parâmetros, tais como a insulina, HOMA-IR e QUICKI, comparando com placebo (P < 0,05). Conclusões: A suplementação com ácidos graxos ômega-3 em pacientes diabéticos tipo 2 melhorou a sensibilidade à insulina, provavelmente devido à diminuição da concentração de AGNE. Arq Bras Endocrinol Metab. 2014;58(4):335-40 .

Effects of carbohydrate-hydration strategies on glucose metabolism, sprint performance and hydration during a soccer match simulation in recreational players.

OBJECTIVES: This study compared the effects of three carbohydrate-hydration strategies on blood glucose concentration, exercise performance and hydration status throughout simulated soccer match-play. DESIGN: A randomized, double-blind and cross-over study design was employed. METHODS: After familiarization, 14 recreational soccer players completed the soccer match simulation on three separate occasions. Participants consumed equal volumes of 9.6% carbohydrate-caffeine-electrolyte (∼ 6 mg/kg BW caffeine) solution with carbohydrate-electrolyte gels (H-CHO), 5.6% carbohydrate-electrolyte solution with electrolyte gels (CHO) or electrolyte solution and electrolyte gels (PL). Blood samples were taken at rest, immediately before exercise and every 15 min during exercise (first half: 15, 30, 45 min; second half: 60, 75, 90 min). RESULTS: Supplementation influenced blood glucose concentration (time × treatment interaction: p<0.001); however, none of the supplementation regimes were effective in preventing a drop in blood glucose at 60 min. Mean sprint speed was 3 ± 1% faster in H-CHO when compared with PL (treatment: p=0.047). Supplementation caused a 2.3 ± 0.5% increase in plasma osmolality in H-CHO (p<0.001) without change in CHO or PL. Similarly, mean sodium concentrations were 2.1 ± 0.4% higher in H-CHO when compared with PL (p=0.006). CONCLUSIONS: Combining high carbohydrate availability with caffeine resulted in improved sprint performance and elevated blood glucose concentrations throughout the first half and at 90 min of exercise; however, this supplementation strategy negatively influenced hydration status when compared with 5.6% carbohydrate-electrolyte and electrolyte solutions.

Comparing effects of carbohydrate (CHO) blockers and trivalent chromium on CHO-induced insulin resistance and elevated blood pressure in rats.

OBJECTIVE: In Sprague-Dawley rats (SD), we compared two categories of natural dietary supplements that influence carbohydrate (CHO) metabolism via different basic mechanisms to ameliorate insulin resistance (IR) and elevated blood pressure (BP) associated with heavy sugar/starch consumption. Two dietary supplements (bean extract and l-arabinose) are often referred to as carb blockers (CBs), because they slow the gastrointestinal absorption of CHO. Trivalent chromium (CR) falls into a group of so-called insulin sensitizers, because its major effect is to enhance peripheral insulin sensitivity. METHOD: We divided 48 mature male SD into 4 groups of 12. The first group received powdered baseline diet alone (Con). The remaining 3 SD groups (groups 2-4) ingested regular rat chow containing 20% w/w sucrose and 20% w/w rice starch. The second group received only this CHO-enriched chow. To the high-CHO diets of the remaining two groups, either CB to slow CHO absorption (CHO + CB) (group 3) or an insulin sensitizer, trivalent CR (CHO + CR; group 4), was added. RESULTS: Compared to Con group 1, adding high CHO content to the diet of group 2 significantly increased circulating glucose levels and systolic BP (SBP). Addition of CB or CR to the feed of groups 3 and 4 overcame the perturbations that occurred with high CHO challenge in group 2; that is, they lowered circulating glucose concentrations to Con levels, enhanced response to exogenous insulin, and overcame the gradual elevation of SBP. Compared to group 2, the two treatment groups (3 and 4) also showed decreased renin-angiotensin system activity, decreased serum angiotensin-converting enzyme activity, and enhanced nitric oxide activity. CONCLUSIONS: Our data indicate that high doses of CB and CR, despite their different mechanisms of action, can completely overcome CHO-induced IR and BP elevations. The data further suggest that CB and CR affect only the changes brought on by heavy CHO ingestion, because IR and SBP in groups 3 and 4 mirrored Con values (group 1), never producing values lower than baseline. Earlier use of CB and CR in the life cycle appears more effective in overcoming CHO-induced perturbations than later use.

Glutamate supplementation is associated with improved glucose metabolism following carbohydrate ingestion in healthy males.

Glutamate is linked to the glycolytic process, particularly when co-ingested with carbohydrate, but its effects on glucose metabolism are poorly characterised. The present study aimed to (1) specifically examine the effects of carbohydrate administration on circulating glutamate concentrations and (2) investigate the effect of increased glutamate availability, independent of carbohydrate ingestion, on glucose metabolism. A total of nine participants underwent four trials: (1) glutamate supplement+carbohydrate drink (GLU+CHO); (2) glutamate supplement+placebo drink (GLU); (3) placebo supplement+carbohydrate drink (CHO); (4) placebo supplement+placebo drink (CON). Following a fasting blood sample, participants ingested monosodium L-glutamate (MSG; 150 mg/kg body weight) or placebo capsules at each trial followed by a 75 g carbohydrate or a non-energy placebo drink 30 min later. Blood samples were taken at 0, 10, 20, 30, 40, 50, 60, 75, 90, 105 and 120 min. Plasma glutamate concentrations were significantly elevated relative to baseline during the GLU (approximately 10-fold) and GLU+CHO trials (approximately 6-fold). The glucose response to a carbohydrate load was blunted when glutamate was increased in the circulation (peak serum glucose: 5.50 (SE 0.54) mmol/l during the GLU+CHO trial v. 7.69 (SE 0.53) mmol/l during the CHO trial, P< 0.05). On average, c-peptide results revealed that insulin secretion did not differ between the GLU+CHO and CHO trials; however, four participants demonstrated increased insulin secretion during the GLU+CHO trial and five participants demonstrated decreased insulin secretion under the same conditions. In conclusion, when administration is staggered, MSG and carbohydrate supplementation can be used to manipulate plasma glutamate; however, future studies should control for this dichotomous insulin response.

Supplementation by thylakoids to a high carbohydrate meal decreases feelings of hunger, elevates CCK levels and prevents postprandial hypoglycaemia in overweight women.

Thylakoids are chlorophyll-containing membranes in chloroplasts that have been isolated from green leaves. It has been previously shown that thylakoids supplemented with a high-fat meal can affect cholecystokinin (CCK), ghrelin, insulin and blood lipids in humans, and can act to suppress food intake and prevent body weight gain in rodents. This study investigates the addition of thylakoids to a high carbohydrate meal and its effects upon hunger motivation and fullness, and the levels of glucose, insulin, CCK, ghrelin and tumour necrosis factor (TNF)-alpha in overweight women. Twenty moderately overweight female subjects received test meals on three different occasions; two thylakoid enriched and one control, separated by 1 week. The test meals consisted of a high carbohydrate Swedish breakfast, with or without addition of thylakoids. Blood samples and VAS-questionnaires were evaluated over a 4-h period. Addition of thylakoids suppressed hunger motivation and increased secretion of CCK from 180 min, and prevented postprandial hypoglycaemia from 90 min following food intake. These effects indicate that thylakoids may intensify signals of satiety. This study therefore suggests that the dietary addition of thylakoids could aid efforts to reduce food intake and prevent compensational eating later in the day, which may help to reduce body weight over time.

Influence of carbohydrate supplementation on skill performance during a soccer match simulation.

OBJECTIVES: This study investigated the influence of carbohydrate supplementation on skill performance throughout exercise that replicates soccer match-play. DESIGN: Experimentation was conducted in a randomised, double-blind and cross-over study design. METHODS: After familiarization, 15 professional academy soccer players completed a soccer match simulation incorporating passing, dribbling and shooting on two separate occasions. Participants received a 6% carbohydrate-electrolyte solution (CHO) or electrolyte solution (PL). Precision, success rate, ball speed and an overall index (speed-precision-success; SPS) were determined for all skills. Blood samples were taken at rest, immediately before exercise, every 15 min during exercise (first half: 15, 30 and 45 min; second half: 60, 75 and 90 min), and 10 min into the half time (half-time). RESULTS: Carbohydrate supplementation influenced shooting (time×treatment interaction: p<0.05), where CHO attenuated the decline in shot speed and SPS index. Supplementation did not affect passing or dribbling. Blood glucose responses to exercise were influenced by supplementation (time×treatment interaction: p<0.05), where concentrations were higher at 45 min and during half-time in CHO compared with PL. Blood glucose concentrations reduced by 30±1% between half-time and 60 min in CHO. CONCLUSIONS: Carbohydrate supplementation attenuated decrements in shooting performance during simulated soccer match-play; however, further research is warranted to optimise carbohydrate supplementation regimes for high-intensity intermittent sports.

The impact of pistachio intake alone or in combination with high-carbohydrate foods on post-prandial glycemia.

BACKGROUND/OBJECTIVES: Dietary strategies that reduce post-prandial glycemia are important in the prevention and treatment of diabetes and coronary heart disease (CHD). This may be achieved by addition of high-quality protein and fat contained in pistachio nuts, to carbohydrate-containing foods or meals. SUBJECTS/METHODS: A total of 10 healthy volunteers (3 males, 7 females); aged 48.3±6.4 years; Body mass index (BMI) 28.0±4.8 kg/m(2) participated in two studies. Study 1 assessed the dose-response effect of 28, 56 and 84 g pistachios consumed alone or co-ingested with white bread (50 g available carbohydrate); Study 2 assessed the effective dose (56 g) of pistachios on post-prandial glycemia consumed with different commonly consumed carbohydrate foods (50 g available carbohydrate). Relative glycemic responses (RGRs) of study meals compared with white bread, were assessed over the 2 h post-prandial period. RESULTS: The RGRs of pistachios consumed alone expressed as a percentage of white bread (100%) were: 28 g (5.7±1.8%); 56 g (3.8±1.8%); 84 g (9.3±3.2%), P<0.001. Adding pistachios to white bread resulted in a dose-dependent reduction in the RGR of the composite meal; 28 g (89.1±6.0, P=0.100); 56 g (67.3±9.8, P=0.009); 84 g (51.5±7.5, P<0.001). Addition of 56 g pistachios to carbohydrate foods significantly reduced the RGR: parboiled rice (72.5±6.0) versus rice and pistachios (58.7±5.1) (P=0.031); pasta (94.8±11.4) versus pasta and pistachios (56.4±5.0) (P=0.025); whereas for mashed potatoes (109.0±6.6) versus potatoes and pistachios, (87.4±8.0) (P=0.063) the results approached significance. CONCLUSIONS: Pistachios consumed alone had a minimal effect on post-prandial glycemia and when taken with a carbohydrate meal attenuated the RGR. The beneficial effects of pistachios on post-prandial glycemia could, therefore, be part of the mechanism by which nuts reduce the risk of diabetes and CHD.