Starchy foods and glycemic index

The association between glycemic index, glycemic load and total carbohydrate intake and risk of premature coronary artery disease: Iran Premature Coronary Artery Disease Study (IPAD) - A Case-Control Study

BACKGROUND AND AIMS

The association between glycemic index (GI), glycemic load (GL), total carbohydrate intake, and risk of cardiovascular diseases has been controversial. Premature coronary artery disease (PCAD) is characterized by the age of onset lower than 55 and 65 respectively in men and women. The aim of the current study is to investigate the relationship between GI, GL and carbohydrate levels and the risk of PCAD in Iran.

METHODS AND RESULTS

In total, 419 healthy people and 553 patients struggling with PCAD have participated in this case-control study. Dietary GI and GL were calculated using a validated food frequency questionnaire at the baseline. Crude and multivariable logistic regression were used to assess the relationship between GI, GL, and total carbohydrate intake and risk of PCAD. The mean age of participants was 51.13 ± 6.90 and 46 % of them were women. A significant direct relationship was observed between higher carbohydrate intake (OR: 1.74, 95%CI: 1.27-2.38) and GL levels (OR: 1.56, 95 % CI:1.14-2.14) and risk of PCAD. These associations were not significant after adjusting for potential variables. No significant association has been observed between GI and odds of PCAD even after controlling for all covariates.

CONCLUSION

We found no significant association between GI, GL, and total carbohydrate intake and risk of premature coronary heart disease. Further observational and clinical trials are required to assess this relationship.

Microencapsulation of Tecoma stans Extracts: Bioactive Properties Preservation and Physical Characterization Analysis

Bioactive compounds from medicinal plants have applications in the development of functional foods. However, since they are unstable, encapsulation is used as a conservation alternative. This work aimed to assess the bioactive properties (antioxidant and hypoglycemic) of different extracts, including the infusion, as well as their spray-dried microencapsulates from Tecoma stans leaves. A factorial design was proposed to determine the best extraction conditions, based on ABTS and DPPH inhibition. Maltodextrin (MD), arabic gum (AG), and a 1:1 blend (MD:AG) were used as encapsulating agents. Moreover, characterization through physicochemical properties, gas chromatography/mass spectrometry (GC-MS) and scanning electron microscopy (SEM) of the best two powders based on the bioactive properties were analyzed. The results showed that the combination of stirring, water, and 5 min provided the highest inhibition to ABTS and DPPH (35.64 ± 1.25 mg Trolox/g d.s. and 2.77 ± 0.01 g Trolox/g d.s., respectively). Spray drying decreased the antioxidant activity of the extract while preserving it in the infusion. The encapsulated infusion with MD:AG had the highest hypoglycemic activity as it presented the lowest glycemic index (GI = 47). According to the results, the microencapsulates could potentially be added in foods to enhance nutritional quality and prevent/treat ailments.

The Application of the Food Insulin Index in the Prevention and Management of Insulin Resistance and Diabetes: A Scoping Review

The food insulin index (FII) is a novel algorithm used to determine insulin responses of carbohydrates, proteins, and fats. This scoping review aimed to provide an overview of all scientifically relevant information presented on the application of the FII in the prevention and management of insulin resistance and diabetes. The Arksey and O'Malley framework and the PRISMA Extension for Scoping Reviews 22-item checklist were used to ensure that all areas were covered in the scoping review. Our search identified 394 articles, of which 25 articles were included. Three main themes emerged from the included articles: 1. the association of FII with the development of metabolic syndrome, insulin resistance, and diabetes, 2. the comparison of FII with carbohydrate counting (CC) for the prediction of postprandial insulin response, and 3. the effect of metabolic status on the FII. Studies indicated that the FII can predict postprandial insulin response more accurately than CC, and that a high DII and DIL diet is associated with the development of metabolic syndrome, insulin resistance, and diabetes. The FII could be a valuable tool to use in the prevention and management of T1DM, insulin resistance, and T2DM, but more research is needed in this field.

The Glycemic Index and Human Health with an Emphasis on Potatoes

Diabetes and obesity are associated with the excessive intake of high-glycemic index (GI) carbohydrates, increased glycemic load (GL) foods, and inactive lifestyles. Carbohydrate-rich diets affect blood glucose levels. GI is an indicator of the impact of a specific food on blood glucose, while GL represents the quantity and quality of carbohydrates in the overall diet and their interactions. There are in vitro and in vivo methods for estimating GI and GL. These values are useful human health markers for conditions such as diabetes, obesity, and pregnancy. Potato is a major starchy vegetable, which is consumed widely and is the fourth most important crop globally. However, the GI of diets rich in starchy vegetables such as potatoes has not been studied in detail. The GI values in potatoes are affected by external and internal factors, such as methods of cooking, methods of processing, resistant starches, cultivation methods, mixed meals and food additions, and hormone levels. This review summarizes how these factors affect the GI and GL associated with diets containing potatoes. Understanding the impacts of these factors will contribute to the development of new and improved potato varieties with low GI values. The consumption of low-GI foods will help to combat obesity. The development of low-GI potatoes may contribute to the development of meal plans for individuals living with diabetes and obesity.

Ultrasound-chilling assisted annealing treatment to produce a lower glycemic index of white rice grains with different amylose content

White rice samples, Chai-Nat1 (CN1) and Jasmin rice (KDML105), were treated with the ultrasound-chilling (UC) and combined with annealing treatments (UC + ANN 45, UC + ANN50, and UC + ANN55). Their physicochemical properties and in vitro glycemic index of rice samples were analyzed. UC + ANN treatments presented pasting temperature, gelatinization temperature and crystallinity increased whereas the glycemic index of both rice samples was decreased as compared to its native. Especially, UC + ANN55 treated rice produced the lowest glycemic index and starch hydrolysis. Moreover, UC + ANN treated CN1 rice exhibited delayed gelatinization temperature, increased gelatinization enthalpy, and decreased glycemic index than KDML105 rice. In addition, Pearson's correlation presented that UC + ANN and amylose content had a highly negative correlation with the glycemic index at p < 0.0.1. The result exhibited that UC followed by ANN show an effective way to modify starch granules with delayed starch hydrolysis reduced glycemic index and properties depending on annealing temperature and rice cultivar.

Effects of Spaghetti Differing in Soluble Fiber and Protein Content on Glycemic Responses in Humans: A Randomized Clinical Trial in Healthy Subjects

This randomized, single blind, cross-over study investigated the glycemic responses to three spaghetti No 7 types differing in dietary protein and soluble fiber content. Fourteen clinically and metabolically healthy, fasting individuals (25 ± 1 years; ten women; BMI 23 ± 1 kg/m²) received isoglucidic test meals (50 g available carbohydrate) and 50 g glucose reference, in random order. GI was calculated using the FAO/WHO method. Capillary blood glucose and salivary insulin samples were collected at 0, 15, 30, 45, 60, and 120 min. Subjective appetite ratings (hunger, fullness, and desire to eat) were assessed by visual analogue scales (VAS, 100 mm) at baseline and 120 min. All three spaghetti types (regular, whole wheat, and high soluble fiber–low carbohydrates) provided low GI values (33, 38, and 41, respectively, on glucose scale) and lower peak glucose values compared to glucose or white bread. No differences were observed between spaghetti No 7 types for fasting glucose, fasting and post-test-meal insulin concentrations, blood pressure (systolic and diastolic), and subjective appetite. Conclusions: all spaghetti No 7 types, regardless of soluble fiber and/or protein content, attenuated postprandial glycemic response, which may offer advantages to glycemic control.

Carbohydrate utilization by the gut microbiome determines host health responsiveness to whole grain type and processing methods

Little is known about how interactions among grain processing, grain type, and carbohydrate utilization (CU) by the microbiome influence the health benefits of whole grains. Therefore, two whole grains - brown rice and whole wheat - and two processing methods - boiling (porridge) and extrusion - were studied for their effects on host metabolic outcomes in mice harboring human microbiomes previously shown in vitro to have high or low CU. Mice carrying either microbiome experienced increases in body weight and glycemia when consuming Western diets supplemented with extruded grains versus porridge. However, mice with the high but not low CU microbiome also gained more weight and fat over time and were less glucose tolerant when consuming extruded grain diets. In high CU microbiome mice, the exacerbated negative health outcomes associated with extrusion were related to altered abundances of Lachnospiraceae and Ruminococcaceae as well as elevated sugar degradation and colonic acetate production. The amplicon sequence variants (ASVs) associated with extruded and porridge diets in this in vivo study were not the same as those identified in our prior in vitro study; however, the predicted functions were highly correlated. In conclusion, mice harboring both high and low CU microbiomes responded to the whole grain diets similarly, except the high CU microbiome mice exhibited exacerbated effects due to excessive acetate production, indicating that CU by the microbiome is linked to host metabolic health outcomes. Our work demonstrates that a greater understanding of food processing effects on the microbiome is necessary for developing foods that promote rather than diminish host health.Abbreviations: CU- carbohydrate utilization; SCFA- short-chain fatty acids; GF- germ-free; HMA, human-microbiome associated; ipGTT- intraperitoneal glucose tolerance test; HOMA-IR- Homeostatic Model Assessment for Insulin Resistance; AUC- area under the glycemia curve; ASV- amplicon sequence variant; lf- low-fat; wd- Western diet; wd_wwp- Western diet containing whole wheat porridge; wd_wwe- Western diet containing whole wheat extrudate; wd_bre- Western diet containing brown rice extrudate; wd_extr- Western diet containing either whole wheat or brown rice extrudate.

Development of a Prediction Model to Estimate the Glycemic Load of Ready-to-Eat Meals

The glycemic index (GI) and glycemic load (GL) of a single food item has been used to monitor blood glucose level. However, concerns regarding the clinical relevance of the GI or GL have been raised on their applicability to a combination of several foods consumed as meal. This study aimed to investigate the glycemic response after consuming commercially purchased ready-to-eat meal and to develop the GL prediction formula using the composition of nutrients in each meal. Glycemic responses were measured in healthy adults with various mixed meals comprising approximately 25 g, 50 g, and 75 g of carbohydrates. After fasting, participants consumed test meals, and the glycemic response was measured for a subsequent 120 min. The GI and GL values for mixed meals were calculated as area under curve for each participant. For the prediction formula, 70 mixed meals were analyzed, of which the GI and GL values of 64 participants were used. The prediction formula produced was as follows: GL = 19.27 + (0.39 × available carbohydrate) – (0.21 × fat) – (0.01 × protein²) – (0.01 × fiber²). We hope that this prediction formula can be used as a useful tool to estimate the GL after consuming ready-to-eat meals.

Associations of cereal grains intake with cardiovascular disease and mortality across 21 countries in Prospective Urban and Rural Epidemiology study: prospective cohort study

OBJECTIVE

To evaluate the association between intakes of refined grains, whole grains, and white rice with cardiovascular disease, total mortality, blood lipids, and blood pressure in the Prospective Urban and Rural Epidemiology (PURE) study.

DESIGN

Prospective cohort study.

SETTING

PURE study in 21 countries.

PARTICIPANTS

148 858 participants with median follow-up of 9.5 years.

EXPOSURES

Country specific validated food frequency questionnaires were used to assess intakes of refined grains, whole grains, and white rice.

MAIN OUTCOME MEASURE

Composite of mortality or major cardiovascular events (defined as death from cardiovascular causes, non-fatal myocardial infarction, stroke, or heart failure). Hazard ratios were estimated for associations of grain intakes with mortality, major cardiovascular events, and their composite by using multivariable Cox frailty models with random intercepts to account for clustering by centre.

RESULTS

Analyses were based on 137 130 participants after exclusion of those with baseline cardiovascular disease. During follow-up, 9.2% (n=12 668) of these participants had a composite outcome event. The highest category of intake of refined grains (≥350 g/day or about 7 servings/day) was associated with higher risk of total mortality (hazard ratio 1.27, 95% confidence interval 1.11 to 1.46; P for trend=0.004), major cardiovascular disease events (1.33, 1.16 to 1.52; P for trend<0.001), and their composite (1.28, 1.15 to 1.42; P for trend<0.001) compared with the lowest category of intake (<50 g/day). Higher intakes of refined grains were associated with higher systolic blood pressure. No significant associations were found between intakes of whole grains or white rice and health outcomes.

CONCLUSION

High intake of refined grains was associated with higher risk of mortality and major cardiovascular disease events. Globally, lower consumption of refined grains should be considered.

The Glycaemic and Insulinaemic Response of Pasta in Chinese and Indians Compared to Asian Carbohydrate Staples: Taking Spaghetti Back to Asia

In this study, we compared the metabolic properties of the Asian staples rice and noodles, which are typically high in glycaemic index (GI), to two types of spaghetti. It is hypothesised that pasta can be a healthy replacement, particularly amongst the Asian population. Thirty Chinese and Indian subjects (17 men, 13 women; BMI: 18.5-25 kg/m2) participated in this randomised crossover trial. On seven occasions, they consumed a glucose reference drink (3 times), white rice, wheat-based mee pok noodles, semolina spaghetti and wholegrain spaghetti. Blood samples were taken to measure glucose and insulin response over a period of 3 h. The current evaluation showed that semolina spaghetti and wholegrain spaghetti can be classified as low GI products, with a GI of 53 and 54, respectively, significantly lower than wheat based mee pok noodles (74) and rice (80) (p < 0.005). In addition, both spaghettis had a lower insulin response compared to rice (p < 0.05). Furthermore, there was no difference in glucose or insulin response between semolina and wholegrain spaghetti. After controlling for gender, ethnicity, fat and fat free mass (kg), the glucose and insulin results did not change. In conclusion, wheat-based pasta can be helpful to modify the carbohydrate-rich Asian diet. Notably, there was no effect of gender, ethnicity and body composition on the glycaemic and insulinaemic response. We speculate that the starch-protein structure as a result of the spaghetti production process is a major driver of its favourable metabolic properties.

The effects of whole grain intake on anthropometric measures in overweight and obese children: a crossover randomised clinical trial

Whole-grain foods have been reported to affect body weight and satiety. However, we are aware of no study in this regard among children. The present study aimed to determine the effects of whole grain consumption on anthropometric measures in overweight or obese children. In this randomised crossover clinical trial, forty-four overweight or obese girls participated. After a 2-week run-in period, subjects were randomly assigned to either intervention (n 44) or non-intervention (n 44) groups. Subjects in the intervention group were given a list of whole-grain foods and were asked to obtain half of their grain servings from these foods each day for 6 weeks. Individuals in the non-intervention group were asked not to consume any of these foods. A 4-week washout period was applied. Then, participants were crossed over to the alternate arm. The measurements were done before and after each phase. Mean age, weight and BMI of participants were 11·2 (sd 1·49) years, 51·2 (sd 10·2) kg and 23·5 (sd 2·5) kg/m2, respectively. Despite the slight reduction in weight and BMI, there were no significant differences in changes in these anthropometric measures. We found a significant effect of whole grain intake on waist circumference (−2·7 v. 0·3 cm, P = 0·04). No significant changes in hip circumference were observed. Changes in the prevalence of overweight, obesity and abdominal obesity were not significantly different. This study indicated a beneficial effect of whole-grain foods on waist circumference in overweight children; however, these foods did not influence weight and BMI.

Palatable Noodles as a Functional Staple Food Made Exclusively from Yellow Peas Suppressed Rapid Postprandial Glucose Increase

Legumes are low-carbohydrate food and are abundant in dietary fiber. In order to provide a functional staple food that does not cause a rapid increase in postprandial blood glucose levels, four kinds of legumes were focused on as ingredients. Noodles made from dehulled yellow pea, unshelled yellow pea, chickpea, and lentil were prepared and evaluated as functional staple foods for controlling blood glucose via an in vitro digestion method. We also measured breaking stress and breaking strain using a creep meter, as well as sensory tests on a 9-point hedonic scale. The noodles made from yellow pea had high values for both breaking stress and breaking strain, and was highly regarded in the sensory tests. Therefore, the noodles made from yellow pea on postprandial glucose and insulin response were measured in a randomized double-blind study (n = 12). The results show that noodles made from yellow pea have a low glycemic index (50.4), and have potential as a functional staple food.

Physicochemical and nutritional properties of rice as affected by parboiling steaming time at atmospheric pressure and variety

To elucidate the effect of different parboiling steaming time on the physicochemical and nutritional quality of rice, four varieties, NERICA1, NERICA7, IR841, and WITA4, were soaked at the same initial temperature (85°C) and steamed for 5, 15, 25, 35, and 45 min. NERICA7 steamed for 25 min recorded the highest head rice yield (71.9%). Nonparboiled IR841 recorded the shortest cooking time (17.0 min), while NERICA1 steamed for 35 min recorded the longest cooking time (26.1 min). NERICA1 steamed for 45 min was the hardest (63.2 N), while nonparboiled IR841 was the softest (28.7 N). NERICA7 recorded higher peak and final viscosities across all steaming times compared to the other varieties. NERICA7 steamed for 35 and 45 min recorded the lowest total starch (77.3%) and the highest protein (13.2%) content, respectively. NERICA7 steamed for 25 and 45 min recorded the highest phosphorus (0.166%), magnesium (572 mg/kg), and potassium (2290 mg/kg) content, respectively. We conclude that, depending on desired physicochemical and nutritional properties, specific varieties and steaming times can be selected to achieve those outcomes.

The nutritional property of endosperm starch and its contribution to the health benefits of whole grain foods

Purported health benefits of whole grain foods in lowering risk of obesity, type 2 diabetes, cardiovascular disease, and cancer are supported by epidemiological studies and scientific researches. Bioactive components including dietary fibers, phytochemicals, and various micronutrients present in the bran and germ are commonly considered as the basis for such benefits. Endosperm starch, as the major constituent of whole grains providing glucose to the body, has been less investigated regarding its nutritional property and contribution to the value of whole grain foods. Nutritional quality of starch is associated with its rate of digestion and glucose absorption. In whole grain foods, starch digestion and glucose delivery may vary depending on the form in which the food is delivered, some with starch being rapidly and others slowly digested. Furthermore, there are other inherent factors in whole grain products, such as phenolic compounds and dietary fibers, that may moderate glycemic profiles. A good understanding of the nutritional properties of whole grain starch is important to the development of food processing technologies to maximize their health benefits.

Upgrading the quality of Africa's rice: a novel artisanal parboiling technology for rice processors in sub-Saharan Africa

In order to increase the quality of locally produced rice, the artisanal parboiling process in West and Central Africa was reconceptualized. A novel parboiling unit was constructed using stainless steel (Inox 304) and fitted directly on an improved stove made from fired bricks. The heat profile at different locations in the unit, the physicochemical properties, cooking properties of the parboiled rice, and the fuel efficiency of the stove were evaluated and compared with that of the traditional system. The heat flow in the new unit was from the top to the bottom while the reverse occurred in the traditional unit. The percent impurities and heat‐damaged grains, swelling and water uptake ratios, amylose content, stickiness, and cohesiveness were lower for rice produced using the improved technology (IT) compared to the traditional technology (TT). Whole grains (%), lightness (L*), yellowness (b*), cooking time, viscosity were higher for rice produced using the IT compared to the TT. Most of physicochemical and cooking properties of rice produced using the IT were not different from that of premium quality imported rice and this was achieved when steaming time was between 20–25 min. The improved stove recorded a lower time to boil water and specific fuel consumption and a higher burning rate and firepower at the hot‐start high‐power phase compared to the traditional stove. Most end users rated the IT as easy and safe to use compared to the TT. The new technology was code‐named “Grain quality enhancer, Energy‐efficient and durable Material (GEM) parboiling technology.”

An appraisal of eighteen commonly consumed edible plants as functional food based on their antioxidant and starch hydrolase inhibitory activities

BACKGROUND

Eighteen edible plants were assessed for their antioxidant potential based on oxygen radical absorbance capacity (ORAC), 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, total phenolics, vitamin C content and various lipophilic antioxidants. The inhibitory activities of the plant extracts against the enzymatic activities of α-amylase and α-glucosidase were also evaluated.

RESULTS

The antioxidant and starch hydrolase activities of the plants varied widely across a single batch of analysis. The ORAC and DPPH radical scavenging EC50 values varied between 298 and 1984 Trolox equivalents g(-1) fresh weight and between 91 and 533 mg kg(-1) fresh weight, respectively. The total phenolics and vitamin C contents varied between 32 and 125 mg gallic acid equivalents g(-1) fresh weight and between 96 and 285 µg g(-1) fresh weight, respectively. All the plants contained neoxanthin, violaxanthin, and α- and β-carotene in varying amounts. Coccinia grandis, Asparagus racemosus, Costus speciosus, Amaranthus viridis and Annona muricata displayed the highest inhibitory activities against starch hydrolases. They were the most efficient against the breakdown of seven starches exposed to the two enzymes as well.

CONCLUSIONS

Overall, the edible plants were observed to display a high antioxidant potential with starch hydrolase inhibitory properties, which were beneficial in their being recognized as functional food.

Starch Origin and Thermal Processing Affect Starch Digestion in a Minipig Model of Pancreatic Exocrine Insufficiency

Although steatorrhea is the most obvious symptom of pancreatic exocrine insufficiency (PEI), enzymatic digestion of protein and starch is also impaired. Low praecaecal digestibility of starch causes a forced microbial fermentation accounting for energy losses and meteorism. To optimise dietetic measures, knowledge of praecaecal digestibility of starch is needed but such information from PEI patients is rare. Minipigs fitted with an ileocaecal fistula with (n = 3) or without (n = 3) pancreatic duct ligation (PL) were used to estimate the rate of praecaecal disappearance (pcD) of starch. Different botanical sources of starch (rice, amaranth, potato, and pea) were fed either raw or cooked. In the controls (C), there was an almost complete pcD (>92%) except for potato starch (61.5%) which was significantly lower. In PL pcD of raw starch was significantly lower for all sources of starch except for amaranth (87.9%). Thermal processing increased pcD in PL, reaching values of C for starch from rice, potato, and pea. This study clearly underlines the need for precise specification of starch used for patients with specific dietetic needs like PEI. Data should be generated in suitable animal models or patients as tests in healthy individuals would not have given similar conclusions.

Acarbose, lente carbohydrate, and prebiotics promote metabolic health and longevity by stimulating intestinal production of GLP-1

The α-glucosidase inhibitor acarbose, which slows carbohydrate digestion and blunts postprandial rises in plasma glucose, has long been used to treat patients with type 2 diabetes or glucose intolerance. Like metformin, acarbose tends to aid weight control, postpone onset of diabetes and decrease risk for cardiovascular events. Acarbose treatment can favourably affect blood pressure, serum lipids, platelet aggregation, progression of carotid intima-media thickness and postprandial endothelial dysfunction. In mice, lifetime acarbose feeding can increase median and maximal lifespan-an effect associated with increased plasma levels of fibroblast growth factor 21 (FGF21) and decreased levels of insulin-like growth factor-I (IGF-I). There is growing reason to suspect that an upregulation of fasting and postprandial production of glucagon-like peptide-1 (GLP-1)-stemming from increased delivery of carbohydrate to L cells in the distal intestinal tract-is largely responsible for the versatile health protection conferred by acarbose. Indeed, GLP-1 exerts protective effects on vascular endothelium, the liver, the heart, pancreatic β cells, and the brain which can rationalise many of the benefits reported with acarbose. And GLP-1 may act on the liver to modulate its production of FGF21 and IGF-I, thereby promoting longevity. The benefits of acarbose are likely mimicked by diets featuring slowly-digested 'lente' carbohydrate, and by certain nutraceuticals which can slow carbohydrate absorption. Prebiotics that promote colonic generation of short-chain fatty acids represent an alternative strategy for boosting intestinal GLP-1 production. The health benefits of all these measures presumably would be potentiated by concurrent use of dipeptidyl peptidase 4 inhibitors, which slow the proteolysis of GLP-1 in the blood.

The use of different reference foods in determining the glycemic index of starchy and non-starchy test foods

Background

Glycemic index (GI) is intended to be a property of food but some reports are suggestive that GI is influenced by participant characteristics when glucose is used as a reference.

Objective

To examine the influence of different reference foods on observed GI.

Design

The GIs of five varieties of rice and a sugary beverage (LoGiCane™) were tested in 31 European and 32 Chinese participants using glucose or jasmine rice as reference foods. The GIs of two ready-to-eat breakfast cereals (Kellogg’s cornflakes and Sustain) were tested in 20 younger and 60 older people using glucose or Sustain as reference foods.

Results

The GIs of rice tended to be higher in the Chinese compared with the Europeans when glucose was used as a reference (jasmine 80 vs 68, P = 0.033; basmati 67 vs 57, P = 0.170; brown 78 vs 65, P = 0.054; Doongara 67 vs 55, P = 0.045; parboiled 72 vs 57, P = 0.011). There were no between-group differences in GI when jasmine rice was the reference. The GIs of breakfast cereals tended to be lower in younger compared with older groups (cornflakes 64 vs 81, P = 0.008; Sustain 56 vs 66, P = 0.054). There was no between-group difference in the GI of cornflakes when Sustain was the reference (cornflakes 115 vs 120, P = 0.64). There was no ethnic difference in GI when glucose was the reference for another sugary food (LoGiCane™ 60 vs 62; P = 0.69).

Conclusions

A starchy reference may be more appropriate than a glucose beverage when attempting to derive universally applicable GI values of starchy foods.

Trial registration

The Chinese/European trial is registered with the Australian New Zealand Clinical Trials Registry as ACTRN12612000519853.

Hypoglycaemic and hypolipidaemic effects of low GI and medium GL Indian diets in type 2 diabetics for a period of 4 weeks: a prospective study

This prospective study reports significant hypoglycaemic and hypolipidaemic effects in type 2 diabetic subjects who were provided the complete diet plan to be on low glycaemic index (GI) and low-medium glycaemic load (GL) Indian vegetarian snacks and mixed meals for 4 continuous weeks. Five millilitres of fasting blood sample drawn at weekly intervals for 4 weeks were analysed for blood glucose, HbA1c and lipid profile. Four weeks later mean blood glucose level of 173.6 mg% decreased to 137.8 mg%, HbA1c of 8% also decreased to 7.1% which reflected the blood glucose level during the study period and hence correlated well with the fall in blood glucose level. Triglyceride level of 244.5 mg% decreased to 164.7 mg% (p < 0.0001) and total cholesterol of 173.5 mg% decreased to 134.6 mg% (p < 0.0001). High-density lipoprotein cholesterol of 33 mg% increased to 39.8 mg% (p < 0.003), very low density lipoprotein (VLDL) cholesterol of 48.9 mg% decreased to 32.9 mg% (p < 0.0001) and low-density lipoprotein cholesterol of 90.1 mg% decreased to 64.3 (p < 0.009). This significant outcome can be improved further if compliance to low GI and low-to-medium GL diet is continued. This may achieve desired glycaemic control and that's limit oxidative stress.

Whole grain intake in relation to body weight: from epidemiological evidence to clinical trials

This viewpoint aims to 1) review the available scientific literature on the relationship between whole grain consumption and body weight regulation; 2) evaluate the potential mechanisms whereby whole grain intake may help reduce overweight and 3) try to understand why epidemiological studies and clinical trials provide diverging results on this topic. All the prospective epidemiological studies demonstrate that a higher intake of whole grains is associated with lower BMI and body weight gain. However, these results do not clarify whether whole grain consumption is simply a marker of a healthier lifestyle or a factor favoring "per se" lower body weight. Habitual whole grain consumption seems to cause lower body weight by multiple mechanisms such as lower energy density of whole grain based products, lower glycemic index, fermentation of non digestible carbohydrates (satiety signals) and finally by modulating intestinal microflora. In contrast with epidemiological evidence, the results of few clinical trials do not confirm that a whole grain low-calorie diet is more effective in reducing body weight than a refined cereal diet, but their results may have been affected by small sample size or short duration of the intervention. Therefore, further intervention studies with adequate methodology are needed to clarify this question. For the time being, whole grain consumption can be recommended as one of the features of the diet that may help control body weight but also because is associated with a lower risk to develop type 2 diabetes, cardiovascular diseases and cancer.

A transgressive brown rice mediates favourable glycaemic and insulin responses

BACKGROUND

We evaluated glycaemic response of a brown rice variant (BR) developed by cross-breeding. Subjects (n = 9) consumed 50 g carbohydrate equivalents of BR, white rice (WR) and the polished brown rice (PR) in comparison to 50 g glucose reference (GLU) in a cross-over design. Plasma glucose and insulin at 0, 15, 45, 60, 90, 120 and 180 min were measured and incremental area under the curve (IAUC) and indices for glucose (GI) and insulin (II) calculated.

RESULTS

BR compared to PR or WR produced the lowest postprandial glycaemia (GI: 51 vs 79 vs 86) and insulinaemia (II: 39 vs 63 vs 68) irrespective of amylose content (19 vs 23 vs 26.5%). Only BR was significantly different from GLU for both plasma glucose (P = 0.012) and insulin (P = 0.013) as well as IAUC(glu) (P = 0.045) and IAUC(ins) (P = 0.031). Glycaemic and insulinaemic responses correlated positively (r = 0.550, P < 0.001). Linear trends for IAUC(glu) and IAUC(ins) indicated a greater secretion of insulin tied in with a greater glycaemic response for WR (r(2) = 0.848), moderate for PR (r(2) = 0.302) and weakest for BR (r(2) = 0.122).

CONCLUSION

The brown rice variant had the lowest GI and II values but these advantages were lost with polishing.

Glycaemic index of some commercially available rice and rice products in Great Britain

The glycaemic response to nine types of rice (white basmati, brown basmati, white and brown basmati, easy-cook basmati, basmati and wild rice, long-grain rice, easy-cook long-grain rice, Thai red rice, Thai glutinous rice) and two types of rice vermicelli (Guilin rice vermicelli, Jiangxi rice vermicelli) commercially available in the United Kingdom were compared against a glucose standard in a non-blind, randomized, repeated-measure, crossover design trial. Fourteen healthy subjects (six males, eight females), mean age 38 (standard deviation 16) years and mean body mass index 21.3 (standard deviation 2.3) kg/m(2), were recruited for the study. Subjects were served portions of the test foods and a standard food (glucose), on separate occasions, each containing 50 g available carbohydrates. Capillary blood glucose was measured from finger-prick samples in fasted subjects (-5 and 0 min) and at 15, 30, 45, 60, 90 and 120 min after the consumption of each test food. For each type of food, its glycaemic index (GI) was calculated geometrically by expressing the incremental area under the blood glucose curve as a percentage of each subject's average incremental area under the blood glucose curve for the standard food. The 10 foods exhibited a range of GI values from 37 to 92. The study indicated that rice noodles, long-grain rice, easy-cook long-grain rice and white basmati rice were low-GI foods, whilst all of the other foods were medium-GI and high-GI foods. The information presented in this paper may be useful in helping people select low-GI foods from the customary foods consumed by the British and Asian populations.

The influence of maternal glycaemia and dietary glycaemic index on pregnancy outcome in healthy mothers

Infant birth weight has increased in Ireland in recent years along with levels of childhood overweight and obesity. The present article reviews the current literature on maternal glycaemia and the role of the dietary glycaemic index (GI) and its impact on pregnancy outcomes. It is known that maternal weight and weight gain significantly influence infant birth weight. Fetal macrosomia (birth weight >4000 g) is associated with an increased risk of perinatal trauma to both mother and infant. Furthermore, macrosomic infants have greater risk of being obese in childhood, adolescence and adulthood compared to normal-sized infants. There is evidence that there is a direct relationship between maternal blood glucose levels during pregnancy and fetal growth and size at birth, even when maternal blood glucose levels are within their normal range. Thus, maintaining blood glucose concentrations within normal parameters during pregnancy may reduce the incidence of fetal macrosomia. Maternal diet, and particularly its carbohydrate (CHO) type and content, influences maternal blood glucose concentrations. However, different CHO foods produce different glycaemic responses. The GI was conceived by Jenkins in 1981 as a method for assessing the glycaemic responses of different CHO. Data from clinical studies in healthy pregnant women have documented that consuming a low-GI diet during pregnancy reduces peaks in postprandial glucose levels and normalises infant birth weight. Pregnancy is a physiological condition where the GI may be of particular relevance as glucose is the primary fuel for fetal growth.

Noninvasive detection of candidate molecular biomarkers in subjects with a history of insulin resistance and colorectal adenomas

We have developed novel molecular methods using a stool sample, which contains intact sloughed colon cells, to quantify colonic gene expression profiles. In this study, our goal was to identify diagnostic gene sets (combinations) for the noninvasive classification of different phenotypes. For this purpose, the effects of a legume-enriched, low glycemic index, high fermentable fiber diet was evaluated in subjects with four possible combinations of risk factors, including insulin resistance and a history of adenomatous polyps. In a randomized crossover design controlled feeding study, each participant (a total of 23; 5-12 per group) consumed the experimental diet (1.5 cups of cooked dry beans) and a control diet (isocaloric average American diet) for 4 weeks with a 3-week washout period between diets. Using prior biological knowledge, the complexity of feature selection was reduced to perform an exhaustive search on all allowable feature (gene) sets of size 3, and among these, 27 had (unbiased) error estimates of 0.15 or less. Linear discriminant analysis was successfully used to identify the best single genes and two- to three-gene combinations for distinguishing subjects with insulin resistance, a history of polyps, or exposure to a chemoprotective legume-rich diet. These results support our premise that gene products (RNA) isolated from stool have diagnostic value in terms of assessing colon cancer risk.