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Glycaemic Properties of Brown Rice
Abstract
Rice, one of the most important global staples, is predominantly consumed as refined/polished white rice (WR). However, refined grain-based diets are known to elicit higher glycaemic responses as well as increase the glycaemic load of diets, thereby increasing the risk of chronic diseases such as type 2 diabetes. In this context, whole grain-based foods and foods with higher dietary fibre, lower glycaemic index (GI) and fat are recommended. Brown rice (BR) is a whole grain with higher levels of nutrients, dietary fibre, vitamins, minerals and health-beneficial phytochemicals, therefore representing a healthier alternative to WR. BR is believed to elicit lower glycaemic responses compared to WR. The glycaemic properties of BR and the factors influencing it, such as varietal variations, cooking methods, processing methods, etc., are discussed in this chapter.
... [14] Several epidemiological and intervention studies support BR over WR. [15,16] Our earlier studies have shown that BR-based diets elicit lower 24-h glycemic responses when compared with WR-based diets. [17,18] We have also shown that in BR-based diets through a 3-month intervention study, there was a potential benefit on HbA1c and lowdensity lipoprotein reduction among participants with the metabolic syndrome and an elevated body mass index (BMI). [15] The physicochemical properties, shelf-life, and glycemic index (GI) of the parboiled BR (both irradiated and non-irradiated) were also assessed (data under publication). ...
... The choice of rice variety and its processing and the form of food, meal composition, and so on influence digestion, absorption, and glycemic response and its associated physiological effects. [18,[21][22][23] However, there are no reports on the glycemic properties of irradiated rice in general and parboiled BR in particular. In the current study, we have evaluated the 24-h glycemic responses of two Indian varieties of the gamma-irradiated parboiled BR-based iso-caloric diets in Asian Indian adults using a continuous glucose monitoring (CGM) system. ...
... Epidemiological evidence indicates that consumption of WR was positively associated with T2D risk, whereas intake of BR was inversely associated. [15,24] Our previous randomized controlled trials [18] have shown higher 24-h glycemic and insulin responses for minimally polished rice (IAUC= 55.5 mg×5 min/dL) and WR-based diets (IAUC= 58.4 mg×5 min/dL) when compared with BR-based diets (IAUC= 34.7 mg×5 min/dL). Mohan et al. [17] used CGM technology to evaluate the effect of replacing WR with BR or BR with legumes among obese Asian adults and reported lower 5-day average IAUC values (day-long glycemic response) and fasting serum insulin levels for BR-based diets. ...
Background: The nutritional importance of brown rice (BR) is well established. Despite several nutritional benefits of BR, its consumption remains limited due to long cooking time and limited shelf-life. BR can be subjected to processing to improve shelf-life. Gamma irradiation is one such strategy, but it could induce changes in the grain and thus affect its glycemic properties. Aims and objectives: The aim of this study was to look at the 24-h glycemic response of irradiated and non-irradiated BR-based iso-caloric diets in Asian Indians. Methods: Fifteen (mean body mass index: 24 ± 2.6 kg/m2) Asian Indian adults without diabetes, aged 25–39 years, participated in this randomized cross-over study. Iso-caloric diets were prepared with two varieties (ADT 43 and Swarna) of parboiled gamma-irradiated brown rice with 750–820 Gy dosage (IBR) and non-irradiated brown rice (NIBR). After the participants consumed these diets, 24-h glycemic responses were recorded using a continuous glucose monitoring system. The mean positive change from baseline glucose concentration was calculated as the incremental area under the curve (IAUC) for both the diets. Results: The percentage difference in 24-h average IAUC was 10% lower in the IBR diets when compared with NIBR diets, irrespective of the variety of BR (P = 0.56). In the case of ADT 43 rice variety, both IBR and NIBR diets showed similar IAUC (P = 0.68). However, the IBR of Swarna rice variety showed 21% lower IAUC when compared with the NIBR diet (P = 0.21). Comparing the IBR varieties, Swarna showed 21% lower IAUC than ADT 43 (P = 0.21), whereas between NIBR varieties, only 0.79% difference was observed between ADT 43 and Swarna (P = 0.93). Conclusions: Gamma irradiation of parboiled BR did not produce significant differences in the 24-h glycemic responses for BR-based diets. Swarna variety was better than ADT 43 with regard to glycemic response. Judicious application of radiation technology to BR varieties may help in shelf-life extension without affecting the glycemic properties.
... Furthermore, another important reason for using BR instead of WR is related to its glycemic index (GI) which is reported to be lower than that of white rice (i.e., 73 ± 4; Atkinson et al., 2008). The lowest GI values of BR have been reported for boiled or steamed BR (68 ± 4 and 50, respectively) (Atkinson et al., 2008;Shobana et al., 2017), although, as seen for other foods, GI values of BR depend on the varietal type, cooking methods, extent of gelatinization, expansion upon cooking, and processing. Several studies reported that consuming BR instead of WR can reduce the glycemic response contributing to lowering the risk of type 2 diabetes (Malik et al., 2019;Yu et al., 2022). ...
Shelf-stable low glycemic index ready-to-eat (RTE) risotto meals (in pouches) containing brown rice and pulses (recipe A = chickpeas; recipe B = lentils, and beans) were developed, stored for 12-months at room temperature, and characterized over time. RTE meals were heated in microwave (replicating home consumption procedure), and analyzed for in vitro starch digestibility, textural attributes, and consumer acceptability. Digestible starch fractions were similar in the formulations during storage, and in vivo testing demonstrated low glycemic indexes (recipe A = 43.5 ± 6.8; recipe B = 31.8 ± 6.5) for the two meals. Hardness of risotto components increased during storage and microwave heating did not fully recover textural attibutes characteristic of the fresh product. Consumers’ (50) acceptability remained high (>5.5 out of 9) until the end of storage. This study demonstrates brown rice with pulses can be used for developing stable and accepted ready-to-eat meals having low glycemic indexes.
... Several factors such as nature of starch, amylose content, amylose/amylopectin ratio, method of cooking, ingredients used and form of food, influence the glycemic properties of rice. [17][18][19][20] The inherent alteration in the nature of starch and higher content of amylose and nondigestible carbohydrates in the rice endosperm is likely to have contributed to slower starch digestibility, resulting in the lower glycemic response elicited by HFWR as compared to RWR. The higher fiber content of HFWR is mainly due to the higher levels of RS (nondigestible) formed in the grain. ...
Background:
We have recently demonstrated a medium glycemic index for novel high fiber white rice (HFWR) variety compared to regular white rice (RWR). However, substituting HFWR for RWR during the whole day's diet may provide extended benefits. The current study aims to assess the 24 h glycemic responses of a HFWR diet compared to a RWR diet.
Methods:
Continuous glucose monitoring (CGM) was used to assess the glycemic profile in 18 overweight, non-diabetic Asian Indians aged 25 to 50 in a randomized cross-over design. The volunteers were provided with iso-caloric (≈2100 kcal/day) HFWR or RWR based diets for four continuous days and switched diets after appropriate washout. Fasting blood samples for insulin assessments were collected at baseline and at the end of 4 day feeding. The glucose response in terms of incremental area under the curve (IAUC) was recorded. General linear model was used to assess the adjusted mean change of fasting insulin level of HFWR compared to RWR. Age and sex were adjusted as confounders in the model.
Results:
The average 24 h glucose response for HFWR was significantly lower (IAUC 66.3 ± 3.1 mg-5 min/dL) than RWR (IAUC 79.8 ± 5.7 mg-5 min/dL). The adjusted mean change in fasting insulin levels from baseline was also lower for HFWR compared to RWR. HFWR elicited a 34% and 30% lower 24 h glycemic and insulin response respectively, compared to RWR.
Conclusion:
Replacing RWR with HFWR may be a healthier alternative for Asian Indians who are at a higher risk of developing type 2 diabetes.
The effect of the physicochemical properties on the digestion behavior of rice was evaluated using the artificial stomach response kit (ARK®). Due to the presence of the external bran layer, brown rice (Rv3) showed delayed rates of gastric emptying, apart from a higher half emptying time (101.80 ± 1.20 min) than milled rice (Rv1 - 57.84 ± 7.49 min) and basmati rice (Rv2 - 77.93 ± 10.18 min). The bran layer of Rv3 inhibited the diffusion of the simulated gastric fluid and resulted in lesser particle breakdown and low glycemic index (GI). In comparison with the shaker digestion process, the mechanical force produced in the ARK® resulted in a higher degree of particle breakdown. An in silico approach successfully predicted the glucose response pattern of rice varieties with no statistical difference (at p< 0.05) with the human in vivo datasets using the output obtained from ARK®. The GI obtained from ARK® was validated with in vivo data using Bland Altmann’s statistical tool which showed good agreement. The morphology, dimensions, capacity of the stomach chamber in the ARK® also resembled in vivo observations. The ARK® is proposed as an improved alternative for in vitro digestion studies.
Rice is an important starchy staple food and generally, rice varieties are known to have a higher glycemic index (GI). Over the years, the significance of GI on human health is being better understood and is known to be associated with several lifestyle disorders. Apart from the intrinsic characteristics of rice, different food processing techniques are known to have implications on the GI of rice. This work details the effect of domestic and industrial-level processing techniques on the GI of rice by providing an understanding of the resulting physicochemical changes. An attempt has been made to relate the process-dependent digestion behavior, which in turn reflects on the GI. The role of food constituents is elaborated and the various in vitro and in vivo approaches that have been used to determine the GI of foods are summarized. Considering the broader perspective, the effect of cooking methods and additives is explained. Given the significance of the cereal grain, this work concludes with the challenges and key thrust areas for future research.
Background and Objectives
In recent years, brown rice (BR) has become popular among the consumers due its nutritional excellence and health benefits as compared to polished or white rice. The objective of this review paper is to compare composition, health benefits, hurdles, shelf life and potential ways to enhance the consumption of BR as compared to white rice.
Findings
Brown rice is the whole grain rice which includes the endosperm, embryo and bran layers. Nutritionally, BR is superior to white rice and an improved source of vitamins, minerals, fibre, γ‐oryzanol and phytochemical components which can support the human health. However, the polishing process removes most of the health promoting components from the BR. Considerable difference have been reported in the nutritional composition of brown and polished rice. Brown rice is gaining popularity among health conscious consumers as compared to white rice but there are also certain hurdles such as a shorter shelf‐life, sensory perception, and lack of awareness about its benefits and availability which limits market potential. However, innovative and optimization process technologies will help in the promotion and improved consumption of BR instead of white rice.
Conclusion
BR is a valuable source of nutritional components which are lost once it is subjected to a polishing process as many nutrients are concentrated in the bran layer. The limitations associated with the consumption of BR have previously effected consumption but the demand for BR has increased which has been attributed to promotion of potential health benefits.
Significance and novelty
BR consumption has potential to contribute to improve the health as part of a healthy diet and reduce the burden of various non‐communicable diseases.
Objective: Low glycaemic index (GI) foods are known to minimize large fluctuations in blood glucose levels and have been suggested to increase fat oxidation. The objective of this study was to simultaneously investigate glucose excursion and substrate oxidation in a whole body calorimetre when Chinese male subjects were provided a low or high GI meal.
Materials/Methods: In a randomized, controlled crossover non blind design, 12 healthy Chinese male adults (BMI 21.8 ± 1.3 kgm−2) attended two sessions consisting of either four low or high glycaemic meals (LGI vs HGI). Breakfast, lunch and snack were consumed in a whole body calorimetre while dinner was consumed at home. Daily changes in glycaemic response (GR) and postprandial GR responses were measured using a continuous glucose monitoring system. The GR was further calculated to obtain the incremental area under the curve (iAUC) for glucose concentrations. Glycaemic variability was calculated as mean amplitude of glycaemic excursion (MAGE). Substrate oxidation was calculated by measuring respiratory quotient and urine nitrogen excretion.
Results: After LGI meals in the whole body calorimetre, iAUC for glucose (P = 0.008) was lower compared to the HGI session. The HGI treatment produced a significantly greater MAGE than the LGI treatment over the 24 hour period (P
Rice is an important staple food for more than half of the world's population. Especially in Asian countries, rice is a major contributor to dietary glycaemic load (GL). Sustained consumption of higher-GL diets has been implicated in the development of chronic diseases such as type 2 diabetes mellitus. Given that a reduction in postprandial glycaemic and insulinaemic responses is generally seen as a beneficial dietary change, it is useful to determine the variation in the range of postprandial glucose (PPG) and insulin (PPI) responses to rice and the primary intrinsic and processing factors known to affect such responses. Therefore, we identified relevant original research articles on glycaemic response to rice through a systematic search of the literature in Scopus, Medline and SciFinder databases up to July 2014. Based on a glucose reference value of 100, the observed glycaemic index values for rice varieties ranged from 48 to 93, while the insulinaemic index ranged from 39 to 95. There are three main factors that appear to explain most of the variation in glycaemic and insulinaemic responses to rice: (1) inherent starch characteristics (amylose:amylopectin ratio and rice cultivar); (2) post-harvest processing (particularly parboiling); (3) consumer processing (cooking, storage and reheating). The milling process shows a clear effect when compared at identical cooking times, with brown rice always producing a lower PPG and PPI response than white rice. However, at longer cooking times normally used for the preparation of brown rice, smaller and inconsistent differences are observed between brown and white rice.
The positive and negative health effects of dietary carbohydrates are of interest to both researchers and consumers.
International experts on carbohydrate research held a scientific summit in Stresa, Italy, in June 2013 to discuss controversies surrounding the utility of the glycemic index (GI), glycemic load (GL) and glycemic response (GR).
The outcome was a scientific consensus statement which recognized the importance of postprandial glycemia in overall health, and the GI as a valid and reproducible method of classifying carbohydrate foods for this purpose. There was consensus that diets low in GI and GL were relevant to the prevention and management of diabetes and coronary heart disease, and probably obesity. Moderate to weak associations were observed for selected cancers. The group affirmed that diets low in GI and GL should always be considered in the context of diets otherwise understood as healthy, complementing additional ways of characterizing carbohydrate foods, such as fiber and whole grain content. Diets of low GI and GL were considered particularly important in individuals with insulin resistance.
Given the high prevalence of diabetes and pre-diabetes worldwide and the consistency of the scientific evidence reviewed, the expert panel confirmed an urgent need to communicate information on GI and GL to the general public and health professionals, through channels such as national dietary guidelines, food composition tables and food labels.
Copyright © 2015 Elsevier B.V. All rights reserved.
The aim of the present study was to determine the parameters related to glycemic and insulinemic responses of type 2 diabetic patients to three low Glycemic Index (GI) breakfast meals and study the effects of each breakfast meal on a standard lunch meal. Breakfast meals were boiled chickpea, red rice (AT 353) meal and atta roti and the standard lunch was red rice (AT 353) with accompaniments. Study design was random cross over (n = 11 age: 40–62 year). GI and Insulinemic Indices (II) of breakfast meals were calculated with white bread as the standard. Serum glucose peak concentration of chickpea was significantly lower than rice (p = 0.0321), roti (p = 0.0019) and bread (p = 0.0001). GI of chickpea, rice and roti meals were 40 ± 7, 64 ± 11 and 88 ± 9 respectively. GI of chickpea was significantly lower than rice (p = 0.0466) and atta roti (p = 0.0016) meals. Chickpea and rice breakfast meals had low GI and atta roti medium GI. GI values in diabetic patients were not significantly different (p > 0.05) from that obtained previously in the same laboratory in healthy individuals. II of chickpea, rice and roti were 76 ± 13, 90 ± 20, 115 ± 28. Glycemic and insulinemic responses showed a linear positive relationship (r = 0.984) indicating that low GI was due to the macronutrients present in the meals. Breakfast meals given in the present study did not lower Glycemic nor insulinemic responses of the subsequent lunch meals. These data are useful especially in primary patient care for modulating diets of diabetic patients.
Background:
Improving the carbohydrate quality of the diet by replacing the common cereal staple white rice (WR) with brown rice (BR) could have beneficial effects on reducing the risk for diabetes and related complications. Hence we aimed to compare the effects of BR, WR, and BR with legumes (BRL) diets on 24-h glycemic and insulinemic responses among overweight Asian Indians.
Subjects and methods:
Fifteen overweight (body mass index, ≥23 kg/m(2)) Asian Indians without diabetes who were 25-45 years old participated in a randomized crossover study. Test meals (nonisocaloric, ad libitum) were identical except for the type of rice and the addition of legumes (50 g/day) and were provided for 5 consecutive days. Glucose profiles were assessed using the Medtronic MiniMed (Northridge, CA) iPro™2 continuous glucose monitoring device. The mean positive change from baseline glucose concentration was calculated as the daily incremental area under the curve (IAUC) on each test day for 5 days and averaged. Fasting serum insulin was measured prior to and at the end of each test diet.
Results:
The percentage difference in 5-day average IAUC was 19.8% lower in the BR group than in the WR group (P=0.004). BRL further decreased the glycemic response (22.9% lower compared with WR (P=0.02). The 5-day percentage change in fasting insulin was 57% lower (P=0.0001) for the BR group and 54% lower for the BRL group compared with the 5-day percentage change observed in the WR group. The glycemic and insulinemic responses to the BR and BRL diets were not significantly different.
Conclusions:
Consumption of BR in place of WR can help reduce 24-h glucose and fasting insulin responses among overweight Asian Indians.
Glycaemic variability challenges the accuracy and use of the glycaemic index (GI). The purpose of the current study was to determine the role of mastication on GI. Using a randomized, controlled, crossover, non-blind design, 15 healthy young subjects returned on 5 separate days for three glucose and two rice test sessions. At the rice sessions, subjects chewed each mouthful either 15 or 30 times. Rice chewed 15 times produced a total glycaemic response (GR; 155 mmol min/l), peak GR (2.4 mmol/l) and GI (68) significantly lower than when chewed for longer (30 times) (184 mmol min/l, 2.8 mmol/l and 88, respectively). The study shows that the GI of rice is affected by the degree of mastication. Chewing 15 times compared with 30 times significantly attenuates the GI, suggesting that mastication may potentially contribute to the glycaemic variability of rice. While future work must establish the extent and limits to which mastication affects glycaemia, it could also explore the potential of using mastication to reduce the glycaemic load of rice.European Journal of Clinical Nutrition advance online publication, 13 November 2013; doi:10.1038/ejcn.2013.231.
In vitro starch digestibility and glycemic indices of three rice varieties- 'Njavara', 'Jyothi' (pigmented rice verities) and 'IR 64' (non-pigmented rice) with similar amylose content were studied. Starch digestibility studies showed differences in glycemic response in three types of rice. The rate of starch hydrolysis was maximum (67.3%) in 'Njavara' rice compared to other two rice varieties. 'Njavara' exhibited the lowest kinetic constant (k) indicating inherent resistance to enzymatic hydrolysis. The glycemic load (GL) and glycemic index (GI) of 'Njavara' were similar to 'Jyothi' and 'IR 64'. Resistant starch content was high in pigmented rice varieties compared to 'IR 64'. The resistant starch content of dehusked and cooked rice increased with the storage time at refrigeration temperature (4°C). 'Njavara' is an easily digestible rice and can be used for baby and geriatric foods.
Diet is an important variable in the course of type 2 diabetes, which has generated interest in dietary options like germinated brown rice (GBR) for effective management of the disease among rice-consuming populations.
In vitro
data and animal experiments show that GBR has potentials as a functional diet for managing this disease, and short-term clinical studies indicate encouraging results. Mechanisms for antidiabetic effects of GBR due to bioactive compounds like
γ
-aminobutyric acid (GABA),
γ
-oryzanol, dietary fibre, phenolics, vitamins, acylated steryl
β
-glucoside, and minerals include antihyperglycemia, low insulin index, antioxidative effect, antithrombosis, antihypertensive effect, hypocholesterolemia, and neuroprotective effects. The evidence so far suggests that there may be enormous benefits for diabetics in rice-consuming populations if white rice is replaced with GBR. However, long-term clinical studies are still needed to verify these findings on antidiabetic effects of GBR. Thus, we present a review on the antidiabetic properties of GBR from relevant preclinical and clinical studies, in order to provide detailed information on this subject for researchers to review the potential of GBR in combating this disease.
Improved and traditional rice varieties grown in Sri Lanka namely, Bg 300, Bg 352, Bg 358, Bg 406, LD 356, Rathkaral, Wedaheenati and Heendikwel were studied for their in vivo glycemic response. Proximate compositions and amylose content of rice were determined according to standard methods and available carbohydrate content was calculated using the difference method. The in vivo glycemic response of selected improved and traditional rice varieties was assessed by determining the glycemic index (GI) using ten healthy subjects. Further, the effect of parboiling of rice on glycemic response was also assessed. The crude protein content was higher in parboiled rice as compared to nonparboiled rice. According to the amylose content, rice varieties studied were classified as intermediate and high amylose rice. The amylose content of Bg 406 was the lowest (20.18% ±0.17) while Rathkaral showed the highest (29%±0.07). The Glycemic index of rice varieties studied ranged from 57±1 to 73± 2. The Wedaheenati variety exhibited the lowest GI while Bg 406 exhibited the highest GI value. Unparboiled Bg 406, LD 356 and parboiled Bg 406 were classified as high GI foods while the rest of the rice varieties studied were categorized as intermediate GI foods. Parboiled rice brought about a reduction in glycemic response in healthy subjects. The maximum reduction of 10% in glycemic index upon parboiling was observed with Bg 352. The traditional rice produced significantly lower (p<0.05) postprandial glycemic effect than did the improved rice. By their low post-prandial glycemic response they could be potentially useful in low GI diets.
Brown rice is a good source of dietary fibre (DF) and contains higher vitamins/minerals than milled rice. The study determined the effect of amylose content (AC) and DF on glucose response (GR) from different varieties of milled and brown rice. Milled and brown rice were used as test foods. They were fed to 9-10 human volunteers containing 50 g available carbohydrate after an overnight fast. GR and the glycemic index (GI) were determined. Results found that Sinandomeng with the lowest AC had a high GI = 75, while PSBRc10 with the highest AC had a low GI = 50. Sinandomeng with a low DF had GI = 75, while its brown rice had GI = 55. Brown rice (IR64) with 23% AC and DF of 2.5 g/100 g had low GI = 51. In conclusion, the GR and GI of the different varieties of cooked milled and brown rice varied depending on its AC and DF contents.
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.
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).
The brown rice variant had the lowest GI and II values but these advantages were lost with polishing.
Because of differences in processing and nutrients, brown rice and white rice may have different effects on risk of type 2 diabetes mellitus. We examined white and brown rice consumption in relation to type 2 diabetes risk prospectively in the Health Professionals Follow-up Study and the Nurses' Health Study I and II.
We prospectively ascertained and updated diet, lifestyle practices, and disease status among 39,765 men and 157,463 women in these cohorts.
After multivariate adjustment for age and other lifestyle and dietary risk factors, higher intake of white rice (> or =5 servings per week vs <1 per month) was associated with a higher risk of type 2 diabetes: pooled relative risk (95% confidence interval [CI]), 1.17 (1.02-1.36). In contrast, high brown rice intake (> or =2 servings per week vs <1 per month) was associated with a lower risk of type 2 diabetes: pooled relative risk, 0.89 (95% CI, 0.81-0.97). We estimated that replacing 50 g/d (cooked,equivalent to one-third serving per day) intake of white rice with the same amount of brown rice was associated with a 16% (95% CI, 9%-21%) lower risk of type 2 diabetes,whereas the same replacement with whole grains as a group was associated with a 36% (30%-42%) lower diabetes risk [corrected].
Substitution of whole grains, including brown rice, for white rice may lower risk of type 2 diabetes. These data support the recommendation that most carbohydrate intake should come from whole grains rather than refined grains to help prevent type 2 diabetes.
The aim of the study was to examine the association of dietary carbohydrates and glycaemic load with the risk of type 2 diabetes among an urban adult Asian Indian population. Adult subjects aged >20 years (n 1843) were randomly selected from the Chennai Urban Rural Epidemiology Study, in Chennai city in southern India. Dietary carbohydrates, glycaemic load and food groups were assessed using FFQ. Oral glucose tolerance tests were performed using 75 g glucose in all subjects. Diagnosis of diabetes was based on WHO Consulting Group criteria. OR for newly detected diabetes were calculated for carbohydrates, glycaemic load and specific food groups comparing subjects in the highest with those in the lowest quartiles, after adjustment for potential confounders such as age, sex, BMI, family history of diabetes, physical activity, current smoking, alcohol consumption and relevant dietary factors. We identified 156 (8.5 %) newly diagnosed cases of type 2 diabetes. Refined grain intake was positively associated with the risk of type 2 diabetes (OR 5.31 (95 % CI 2.98, 9.45); P < 0.001). In the multivariate model, after adjustment for potential confounders, total carbohydrate (OR 4.98 (95 % CI 2.69, 9.19), P < 0.001), glycaemic load (OR 4.25 (95 % CI 2.33, 7.77); P < 0.001) and glycaemic index (OR 2.51 (95 % CI 1.42, 4.43); P = 0.006) were associated with type 2 diabetes. Dietary fibre intake was inversely associated with diabetes (OR 0.31 (95 % CI 0.15, 0.62); P < 0.001). In urban south Indians, total dietary carbohydrate and glycaemic load are associated with increased, and dietary fibre with decreased, risk of type 2 diabetes.
White rice is an indispensable staple food in Japan, although it is a high glycemic index food. The objective of this study was to estimate how barley cooked with white rice might affect postprandial glucose, insulin and desacyl ghrelin concentrations as well as fullness. The study was conducted in randomized crossover design with nine healthy subjects. Blood glucose, insulin, free fatty acid and desacyl ghrelin concentrations and subjective levels of fullness and hunger were measured for 240 min after intake of glucose, white rice, 30% rolled barley (30BAR), 50% rolled barley (50BAR) and 100% rolled barley (100BAR) containing 75 g of available carbohydrate. Postprandial glucose and insulin levels were suppressed by intake of 30BAR, 50BAR and 100BAR comparing with those of white rice. Area under the curves of plasma glucose and insulin concentrations was reduced by barley intake in a dose-dependent manner. Although plasma desacyl ghrelin levels decreased postprandially, the degree of reduction was suppressed by barley intake in a dose-dependent manner. Postprandial desacyl ghrelin levels can be a sensitive biomarker of carbohydrate metabolism. The combination of white rice with barley plays a beneficial role in preventing and treating type 2 diabetes, obesity and other metabolic diseases.
To systematically tabulate published and unpublished sources of reliable glycemic index (GI) values.
A literature search identified 205 articles published between 1981 and 2007. Unpublished data were also included where the data quality could be verified. The data were separated into two lists: the first representing more precise data derived from testing healthy subjects and the second primarily from individuals with impaired glucose metabolism.
The tables, which are available in the online-only appendix, list the GI of over 2,480 individual food items. Dairy products, legumes, and fruits were found to have a low GI. Breads, breakfast cereals, and rice, including whole grain, were available in both high and low GI versions. The correlation coefficient for 20 staple foods tested in both healthy and diabetic subjects was r = 0.94 (P < 0.001).
These tables improve the quality and quantity of GI data available for research and clinical practice.
Three high-amylose rice varieties, IR42, IR36, and IR62, with similar chemical composition including amylose content (26.7-27.0%), were cooked under the same conditions and tested for in vitro digestibility as well as blood glucose and insulin responses in healthy human volunteers. The starch-digestion rate and the glycemic and insulin responses were the highest in IR42, followed by IR36 and, then IR62. The differences were not due to unabsorbed carbohydrate but were related to their physicochemical properties, such as gelatinization temperature, minimum cooking time, amylograph consistency, and volume expansion upon cooking. When the three varieties were cooked for their minimum cooking time, they had the same degree of gelatinization and their starch-digestion rates and glycemic responses were similar. We conclude that amylose content alone is not a good predictor of starch-digestion rate or glycemic response. Rice varieties with similar high-amylose contents can differ in physicochemical (gelatinization) properties and this, in turn, can influence starch digestibility and blood glucose response.
Glycemic index responses of two cooked rices and six types of cooked noodles consumed by eight noninsulin-dependent diabetics correlated positively with in vitro starch digestibility of food slurry and negatively with amylose content of the food. Glutinous (waxy) rice had the highest values, and mung bean noodles the lowest.
The purpose of the study was to compare the in vitro starch digestibility and postprandial blood glucose response of conventionally-cooked versus factory-processed foods. Carbohydrate portions of three unprocessed foods (boiled rice, sweet corn, and potato) and six processed foods (instant rice, Rice Bubbles, corn chips, Cornflakes, instant potato, and potato crisps) were incubated for 3 h with human saliva and porcine pancreatin. The proportion of starch digested was significantly higher (p less than 0.05) for the processed forms of rice, corn, and potato compared with the respective conventionally cooked foods. In six healthy volunteers who ingested 50 g carbohydrate portions of the above foods the processed foods produced a higher glycemic index (p less than 0.05) in all but one instance. The exception was potato crisps which gave a similar glycemic response to boiled potato.
To study the influence of parboiling, amylose content and gelatinisation temperature of rice on the postprandial blood glucose and insulin responses in non-insulin-dependent diabetic (NIDDM) subjects.
Twelve NIDDM subjects ingested high (27%) and low amylose content five test meals of 50 g available carbohydrates as white bread, cooked polished rice with high (27%) and low amylose content (12%) with different gelatinisation temperature and as nonparboiled and parboiled. The meals were taken in random order after a 12h fast with approximately 7 days interval.
The glycaemic indices (GI) of all rice varieties were lower than that of white bread (P <0.001). Furthermore, GI of parboiled rice with a high amylose content was lower than that of parboiled rice with a low amylose content (50 +/- 7 vs 73 +/- 7, P <0.01). No differences were 47 +/- 4, n.s.), nor between non-parboiled and parboiled rice (50 +/- 7 vs 53 +/- 7, n.s.). Insulin responses to the five test meals were not significantly different in the NIDDM subjects.
In NIDDM subjects the investigated rices were all low glycaemic as compared to white bread,independent of parboiling and physico-chemical characteristics. The mildparboiling process used did not influence GI. The study showed that the amylose content, but not the gelatinisation temperature, may be an useful criterion in selection of low GI rices also after parboiling.
To study the influence of parboiling and the severity of the process on glycaemic and insulinaemic responses to rice in type 2 diabetes. Moreover, to examine changes in starch structure related to parboiling, which may affect the metabolic responses and digestibility.
Nine type 2 diabetic subjects ingested four test meals: white bread (WB) and three meals of cooked polished rice of the same variety being non-parboiled (NP), mildly traditionally parboiled (TP) and severely pressure parboiled (PP). The participants ingested the test meals (50 g available carbohydrates) on separate occasions after an overnight fast.
Outpatient clinic, Dept. Endocrinology and Metabolism, Aarhus University Hospital, Denmark.
All three rice samples elicited lower postprandial plasma glucose response (NP: 335+/-43; TP: 274+/-53; PP: 231+/-37 mmol/1*180 min.; means+/-s.e.m.) than white bread (626+/-80; P<0.001), within rice samples PP tended to be lower than NP (P=0.07). The glycaemic indices were: NP: 55+/-5, TP: 46+/-8 and PP: 39+/-6, and lower for PP than NP (P<0.05). The insulin responses were similar for the three rice meals, which were all lower than that to white bread (P<0.001). Differential scanning calorimetry showed the presence of amylose-lipid complexes in all rice samples and of retrograded amylopectin in PP. Amylose retrogradation was not detected in any of the rice samples.
All rice test meals were low-glycaemic in type 2 diabetic subjects. There was no effect of TP on glycaemic index, whereas PP reduced the glycaemic index by almost 30% compared to NP. Sponsorship: The Royal Veterinary and Agricultural University, Aarhus University Hospital, Danish International Development Assistance (DANIDA), Ministry of Foreign Affairs and the 'Konsul Johannes Fogh-Nielsens og Fru Ella Fogh-Nielsens Legat' foundation.
To examine the relationship between dietary carbohydrates, glycemic load and high-density lipoprotein cholesterol (HDL-C) concentrations in Asian Indians, a high-risk group for diabetes and premature coronary artery disease.
The study population comprised of 2043 individuals aged >/=20 years randomly selected from Chennai Urban Rural Epidemiological Study (CURES), an ongoing population-based study on a representative population of Chennai (formerly Madras) city in southern India. Participants with self-reported history of diabetes or heart disease or on drug therapy for dyslipidemia were excluded from the study. Dietary carbohydrates, glycemic index and glycemic load were assessed using a validated interviewer administered semiquantitative Food Frequency Questionnaire (FFQ).
Both dietary glycemic load (P<0.0001) and total dietary carbohydrate intake (P<0.001) were significantly associated with higher serum triglyceride levels and lower serum HDL-C levels. For the lowest to highest quintile of glycemic load, the multivariate-adjusted mean HDL-C values were 44.1 mg per 100 ml and 41.2 mg per 100 ml (6.6% difference, P for trend<0.001), while for total carbohydrate it was less (5% difference, P for trend=0.016). The pattern of decrease in HDL-C for the lowest to highest quintile of glycemic load was more pronounced among men (1st vs 5th quintile: adjusted HDL-C: 4.3 mg per 100 ml decrease (10.3%)) than women (1st vs 5th quintile: adjusted HDL-C: 3.2 mg per 100 ml decrease (6.9%)).
Our findings indicate that both total carbohydrates and dietary glycemic load intake are inversely associated with plasma HDL-C concentrations among Asian Indians, with dietary glycemic load having a stronger association.
Background and Objectives: To evaluate the effect of polishing on the glycemic properties of Indian parboiled brown rice. Methods and Study Design: We evaluated the effect of different degrees of polishing on the glycemic and insulinemic responses of Bapatla (BPT-5204), Indian parboiled Indica rice variety. Brown rice (BR), under milled rice (UMR) and white rice (WR) with 2.3% and 9.7% degree of polishing (DOP), respectively, were prepared and evaluated for the glycemic properties. Incremental Area Under the Curves (IAUC) were estimated for both glycemic index (GI) in 12 healthy participants (6 men, 6 women) and 24 hr glycemic response studies in 13 overweight participants (5 men, 8 women) using continuous glucose monitoring (CGM) system with ≈ 2000kcal/day rice diets. Differences in pre and post meal insulin (Δ) were assessed. Results: The GI of WR (GI=79.6) and UMR (GI=73) were significantly higher than BR (GI=57.6) (p < 0.01). Similar results were obtained for 24 hr glycemic responses [IAUC: WR=58.4, UMR=55.5, BR=34.7 mg*5 min/dL, respectively]. The Δ Insulin responses were lower with BR meals compared with UMR and WR (p=0.025; p=0.003). Conclusions: Both UMR and WR had a high GI while BR had a medium GI. This could have influenced the 24 h glycaemic and insulinemic responses of BR which had the lowest responses as compared with UMR and WR, and the latter two had similar higher responses. Thus any degree of polishing leads to higher glycaemic responses.
Abstract Rice is the principle staple and energy source for nearly half the world's population and therefore has significant nutrition and health implications. Rice is generally considered a high glycaemic index (GI) food, however this depends on varietal, compositional, processing and accompaniment factors. Being a major contributor to the glycaemic load in rice eating populations, there is increasing concern that the rising prevalence of insulin resistance is as a result of the consumption of large amounts of rice. Devising ways and means of reducing the glycaemic impact of rice is therefore imperative. This review gathers studies examining the GI of rice and rice products and provides a critical overview of the current state of the art. A table collating published GI values for rice and rice products is also included.
The present study aimed to compare the chemical compositions and physicochemical properties of Jasmine brown rice (Oryza sativa cultivar Kao Dok Mali 105). Brown rice was cooked by various cooking methods, namely electric cooker, microwave oven, steaming, and conventional method. The results indicated that the conventional cooking method significantly reduced protein and fat content. The lowest degree of gelatinization was observed in rice cooked by steaming method. The water to rice ratio of 2:1 showed significantly higher on the hardness, chewiness, and cohesiveness, but lower on the degree of gelatinization than those of other cooking methods.
The purpose of this work was to compare in vitro and in vivo starch digestibility of a typical Italian variety of rice (Fino Ribe) industrially processed in three different ways (polished, parboiled or quick-cooking parboiled). Portions of the three samples were digested in vitro with pepsin and pancreatic α-amylase. Percentages of starch digested were significantly (P < 0·05) lower in parboiled and quick-cooking parboiled rices than in polished rice. Completeness of starch digestion in vivo and glycemic response were evaluated using the breath-H2 and the glycemic index techniques in nine healthy volunteers. Both the processed rices had a lower (P < 0·05) glycemic index than polished rice but no evidence of higher malabsorbed starch.
The glycemic responses of rice processed in different ways and cooked for different lengths of time have been studied in diabetic subjects. The mean glycemic index (GI) of regular long grain white rice (83±5) in 5 IDDM and 13 NIDDM patients was significantly below that of white bread (100, p<0.01), and significantly greater than that of long grain white parboiled rice (67±5, p<0.01). In additional tests on the 13 NIDDM patients, instant rice had a lower GI (65±5, p<0.01) than regular rice. Undercooking rice reduced the glycemic response of regular (GI of 58±4, p<0.01) but not parboiled rice (GI of 54±4, NS). GI values for the 7 NIDDM subjects with fasting blood glucose (FBG) levels below 8.3 mmol/l were not significantly different from those for the 6 NIDDM subjects with FBG above 8.3 mmol/l (r=0.911, n=8, p<0.01). It is concluded that differences in the glycemic response to rice reported in the literature are largely explained by the differences in GI for regular and parboiled rices. The glycemic responses to rice were similar in all groups of diabetic subjects studied.
The glycemic index (GI) is a physiological assessment of a food's carbohydrate content through its effect on postprandial blood glucose concentrations. Evidence from trials and observational studies suggests that this physiological classification may have relevance to those chronic Western diseases associated with overconsumption and inactivity leading to central obesity and insulin resistance. The glycemic index classification of foods has been used as a tool to assess potential prevention and treatment strategies for diseases where glycemic control is of importance, such as diabetes. Low GI diets have also been reported to improve the serum lipid profile, reduce C-reactive protein (CRP) concentrations, and aid in weight control. In cross-sectional studies, low GI or glycemic load diets (mean GI multiplied by total carbohydrate) have been associated with higher levels of high-density lipoprotein cholesterol (HDL-C), with reduced CRP concentrations, and, in cohort studies, with decreased risk of developing diabetes and cardiovascular disease. In addition, some case-control and cohort studies have found positive associations between dietary GI and risk of various cancers, including those of the colon, breast, and prostate. Although inconsistencies in the current findings still need to be resolved, sufficient positive evidence, especially with respect to renewed interest in postprandial events, suggests that the glycemic index may have a role to play in the treatment and prevention of chronic diseases.
To determine the glycemic index (GI), glycemic load (GL) and insulinemic index (II) of five starchy foods that are commonly used in Chinese diets.
Ten healthy subjects aged between 20-30 years were recruited. Each subject was asked to consume 50 g of available carbohydrate portions of test foods and reference food. Finger capillary blood samples were collected at the start of eating and 15, 30, 45, 60, 90 and 120 min after consumption. The GI and II of foods were calculated from the ratio of incremental area under the glucose/insulin response curves of test and reference foods. The GL for each test food was determined from its GI value and carbohydrate content.
The results showed that brown rice elicited the highest postprandial glucose and insulin responses, followed by taro, adlay, yam and mung bean noodles, which produced the lowest. Among the five starchy foods, brown rice evoked the highest GI and GL at 82 ± 0.2 and 18 ± 0.2, followed by taro (69 ± 0.4, 12 ± 0.2), adlay (55 ± 0.4, 10 ± 0.2), yam (52 ± 0.3, 9 ± 0.0) and mung bean noodles (28 ± 0.5, 7 ± 0.2), respectively. The II values of the test foods corresponded with GI values. Similarly, brown rice gave the highest II at 81 ± 0.1, followed by taro (73 ± 0.3), adlay (67 ± 0.3), yam (64 ± 0.5) and mung bean noodles (38 ± 0.3). All five starchy foods had lower GI, GL and II than reference bread (P < 0.05).
The GI, GL and II values of starchy foods provide important information for the public to manage their diet and could be useful for the prevention of lifestyle-related diseases such as diabetes mellitus.
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 study was to evaluate the association of refined grains consumption with insulin resistance and the metabolic syndrome in an urban south Indian population. The study population comprised 2042 individuals aged > or = 20 years randomly selected from the Chennai Urban Rural Epidemiology Study (CURES), a cross-sectional study on a representative population of Chennai, southern India. The metabolic syndrome was defined according to modified Adult Treatment Panel III guidelines; and insulin resistance, by the homeostasis assessment model. The mean refined grain intake was 333 g/d (46.9% of total calories) in this population. After adjustment for age, sex, body mass index, metabolic equivalent, total energy intake, and other dietary factors, higher refined grain intake was significantly associated with higher waist circumference (8% higher for the highest vs the lowest quartile, P for trend < .0001), systolic blood pressure (2.9%, P for trend < .0001), diastolic blood pressure (1.7%, P for trend = .03), fasting blood glucose (7.9%, P for trend = .007), serum triglyceride (36.5%, P for trend < .0001), low high-density lipoprotein cholesterol (-10.1%, P for trend < .0001), and insulin resistance (13.6%, P < .001). Compared with participants in the bottom quartile, participants who were in the highest quartile of refined grain intake were significantly more likely to have the metabolic syndrome (odds ratio, 7.83; 95% confidence interval, 4.72-12.99). Higher intake of refined grains was associated with insulin resistance and the metabolic syndrome in this population of Asian Indians who habitually consume high-carbohydrate diets.
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.
We determined the glycemic (GI) and insulin-index (II) values for 12 rice products, using eight healthy subjects. The products were brown and white versions of three commercial varieties of rice [two varieties with normal amylose content (20%) and the other with 28% amylose], a waxy rice (0-2% amylose), a converted rice, a quick-cooking brown rice, puffed rice cakes, rice pasta, and rice bran. The GI of the rices ranged from 64 +/- 9 to 93 +/- 11, where glucose = 100. The high amylose rice gave a lower GI and II (P < 0.01) than did the normal-amylose and waxy-rice varieties. The converted rice and most other rice products gave a high GI. Insulin indices correlated positively with GI (r = 0.75, P < 0.05), although they were lower than expected. These results indicate that many varieties of rice, whether white, brown, or parboiled, should be classified as high GI foods. Only high-amylose varieties are potentially useful in low-GI diets.
This study was designed to determine whether the rate of hydrolysis of different starches by pancreatic amylase in vitro was proportional to the postprandial glucose and insulin response to those starches after oral ingestion. Lean young men consumed four test meals of rice containing 75 g starch: white rice, unpolished (brown) rice, ground white rice, and ground brown rice. Postprandial glucose and insulin responses were measured over 4 h and showed the following pattern: ground white rice congruent to ground brown rice greater than white rice greater than brown rice. The maximum increases in blood glucose after the four meals were brown rice 0.9 mM, white rice 1.5 mM, ground brown rice 3.3 mM, and ground white rice 3.6 mM. Samples of the cooked rices were incubated in vitro with pancreatic amylase for 30 min and the percentage starch hydrolysis determine. The relative rates of starch hydrolysis correlated very closely with the peak glucose responses: brown rice 17.6%, white rice 30.8%, ground brown rice 68.2% and ground white rice 71.8%. These results indicated that the rate of intestinal hydrolysis of starch is an extremely important determinant of the metabolic responses to a particular starch. The rate of starch hydrolysis can be determine simply by an in vitro method and should assist the design of diets for the treatment of diabetes.
The determine the effect of different foods on the blood glucose, 62 commonly eaten foods and sugars were fed individually to groups of 5 to 10 healthy fasting volunteers. Blood glucose levels were measured over 2 h, and expressed as a percentage of the area under the glucose response curve when the same amount of carbohydrate was taken as glucose. The largest rises were seen with vegetables (70 +/- 5%), followed by breakfast cereals (65 +/- 5%), cereals and biscuits (60 +/- 3%), fruit (50 +/- 5%), dairy products (35 +/- 1%), and dried legumes (31 +/- 3%). A significant negative relationship was seen between fat (p less than 0.01) and protein (p less than 0.001) and postprandial glucose rise but not with fiber or sugar content.
In order to assess the relationship between metabolic responses and satiety, four men and five women ate two pairs of foods containing 50 g of available carbohydrate, ordinary and quick-cooking rice and high- and low-amylose puffed rice. Plasma glucose and insulin levels and satiety ratings were assessed over 2 h and food intake measured immediately thereafter. The area under the curve (AUC) of the 2-h glucose response was 1.6 times greater after quick-cooking rice than that for ordinary rice. Similarly, the glucose AUC for the low-amylose rice was 1.5 times higher than that of the high-amylose rice. Insulin responses followed the pattern of the glucose responses. Conversely, the satiety AUC was 1.5 times higher for ordinary rice than for the quick-cooking rice, and 1.5 times higher for high-amylose than for low-amylose rice. Food intake (g) immediately after each 2-h session was significantly related to both the satiety AUC and the last rating score, thereby corroborating the satiety ratings. A significant negative association was found between the individual insulin and satiety AUC responses to the four foods. These results suggest that increased rate of starch digestion and higher insulin responses are associated with lessened satiety.
The objective of this study was to provide national estimates of whole-grain intake in the United States, identify major dietary sources of whole grains and compare food and nutrient intakes of whole-grain consumers and nonconsumers.
Data were collected from 9,323 individuals age 20 years and older in USDA's 1994-96 Continuing Survey of Food Intakes by Individuals through in-person interviews on two non-consecutive days using a multiple-pass 24-hour recall method. Foods reported by respondents were quantified in servings as defined by the Food Guide Pyramid using a new database developed by the USDA. Whole-grain and nonwhole-grain servings were determined based on the proportion, by weight, of the grain ingredients in each food that were whole grain and nonwhole grain. Sampling weights were applied to provide national probability estimates adjusted for differential rates of selection and nonresponse. Then, t tests were used to assess statistically significant differences in intakes of nutrients and food groups by whole-grain consumers and nonconsumers.
According to the 1994-96 survey, U.S. adults consumed an average of 6.7 servings of grain products per day; 1.0 serving was whole grain. Thirty-six percent averaged less than one whole-grain serving per day based on two days of intake data, and only eight percent met the recommendation to eat at least three servings per day. Yeast breads and breakfast cereals each provided almost one-third of the whole-grain servings, grain-based snacks provided about one-fifth, and less than one-tenth came from quick breads, pasta, rice, cakes, cookies, pies, pastries and miscellaneous grains. Whole-grain consumers had significantly better nutrient profiles than nonconsumers, including higher intakes of vitamins and minerals as percentages of 1989 Recommended Dietary Allowances and as nutrients per 1,000 kilocalories, and lower intakes of total fat, saturated fat and added sugars as percentages of food energy. Consumers were significantly more likely than nonconsumers to meet Pyramid recommendations for the grain, fruit and dairy food groups.
Consumption of whole-grain foods by U.S. adults falls well below the recommended level. A large proportion of the population could benefit from eating more whole grain, and efforts are needed to encourage consumption.
The objectives were to examine the feasibility of using white rice as a reference food in the study of glycemic index (GI) and to examine the GI values of both single and mixed meal foods among rice species, processed rice products, beans, and dairy products.
Subjects were served with 50 g carbohydrate content of white rice at least two times (maximum three times) and test food once after separate overnight fasts. Capillary blood glucose measurements were carried out before and during 120 min after each food load.
The study was carried out in an outpatient setting.
A total of 58 (38 females and 20 males) nondiseased subjects, mean aged 37 y and mean BMI 22 kg/m(2) were included.
The correlation between incremental area under curve of white rice and glucose was r=0.853 (n=10, P <0.0001) and white rice was considered suitable to be used as a reference food. Among mixed meal foods, the combination of carbohydrate foods with vinegar, dairy products, and bean products significantly decreased the GI value of white rice of 20-40%. The reduction of GI occurred whether the foods were taken together, before or after rice intake. GI of noodles such as udon, soba, and spaghetti showed low GI values.
White rice could be used as a reference food in determining GI values of foods. A total of 32 single and mixed meal Japanese common food products were examined for their GI values.
Effects of pre-germinated brown rice (PGBR) on postprandial blood glucose and insulin concentrations were compared with brown rice (BR) and white rice (WR) in two studies. In the first study, we investigated the time course of postprandial blood glucose and insulin concentrations after ingesting 25% (W/V) glucose solution, PGBR, BR or WR in 19 healthy young subjects. In the second study, dose-dependent effect of PGBR on the time course of postprandial blood glucose concentrations was compared among 4 different mixtures of PGBR and WR in 13 healthy young subjects. They were solely PGBR, 2/3 PGBR (PGBR: WR = 2 : 1), 1/3 PGBR (PGBR : WR = 1 : 2) and solely WR. Each sample was studied on a different day. The samples were selected randomly by the subjects. All the rice samples contained 50 g of available carbohydrates. The previous day the subjects ate the assigned dinner by 9:00 pm and then were allowed only water until the examination. The next morning, they ingested each test rice sample with 150 ml of water in 5-10 min. Blood was collected into capillary tubes from finger at 0, 30, 60, 90 and 120 min after the ingestion. The incremental areas under the curve (IAUC) of blood glucose concentrations (IAUC-Glc) for 120 min after the administration of PGBR and BR were lower than those after WR. In contrast the IAUC-Glc of BR and PGBR were not different (Study 1). The higher the ratio of PGBR/WR, the lower the glycemic index became (Study 2). These results suggest that intake of PGBR instead of WR is effective for the control of postprandial blood glucose concentration without increasing the insulin secretion.
Glycaemic index of eight types of commercial rice in Malaysia
- Bnm Yusof
- Ra Talib
- Na Karim
Carbohydrates in human nutrition: report of joint FAO/WHO expert consultation
- Fao Who
Dietary intake and food sources of whole grains among US children and adolescents: data from the 1994-1996 continuing survey of food intakes by individuals
- L Harnack
- Sah Walters
- Dr Jacobs