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Glycaemic index of selected staple carbohydrate-rich foods commonly consumed in Botswana
Abstract
Objectives: Data on the glycaemic index (GI) of foods commonly consumed in Botswana are lacking. The present study aimed to evaluate the GI of some of the staple carbohydrate-rich foods eaten in Botswana. Design, setting and subjects: Fifty university student volunteers were divided into five groups. Members of each group consumed different test foods based on wheat, maize, sorghum, millet and morama beans to supply 50 g of available carbohydrate after 10-12 hours of overnight fasting. GI was determined using a standard method with white bread. Outcome measures: The GI values were calculated after measuring blood glucose levels before and after ingestion at 0, 15, 30, 45, 60, 90 and 120 minutes. Results: The results showed a clear variation in the GI values for the same food when consumed by different individuals. In addition, variations were observed in the GI values of test foods based on the same material. On average, wheat-based foods exhibited the highest GI values (103.1), followed by millet-based foods (95.3), sorghum-based foods (92.5), maize-based foods (9.1) and morama-based foods (86.4). Of the tested food, mapakiwa (wheat-based) had the highest GI (110.6) whereas roasted morama had the lowest GI (82.8). Conclusion: These results could form the basis of dietary advice to consumers, and particularly patients with diabetes. Further studies are needed on more of the commonly consumed foods in Botswana.
... The blood sugar response of these meals also grows slowly than that observed in the subjects who consumed sucrose and glucose solutions, which reach the peak of 160 at 40 min (Fig. 1). This remark must be due to the presence of dietary fibers in okra, which enhance the reduction of glycemic index reported by Mahgoub et al. [31]. In addition, dishes with fresh okra had shown slower glycemic response generally than dried okra dishes. ...
... This trend can be justified by the fact that glucose is a monosaccharide which has a quick blood absorption in human organism. This agreement is in accordance with the findings of Mahgoub et al. [31] who reported that sucrose is a disaccharide composed of glucose and fructose molecules and the ingestion of glucose solution alone raises rapidly the glycemic index than other carbohydrate components. Importantly, the present study provided the first evidence that the consumption of staple maize with fresh okra containing smoked fish reduces the risk of diabetes development induced by the consumption of unknown glycemic indexes foods. ...
... However, glycemic index of the tested meals made up of peeled maize was between 37.87 % (MD/GFP) and 115.76 % (MD/GSV) whereas, the unpeeled maize meals have the glycemic index in the range of 34.39 % (MND/GFP) to 53.05 % (MND/GFV). Except MD/GSV meal (115.76 %), the glycemic index values of these foods made up with corn staple as source of carbohydrate are lower than those found by Mahgoub et al. [31] for maize (91.00 %) foods consumed in Botswana. ...
... Furthermore, food mixtures and consistency may affect the bioavailability and hence the GI values for the individual. According to Mahgoub [31] mixed foods may increase or decrease their GI values depending on the glucose composition of the food items while hardness or softness of the food may influence the availability of its glucose to the blood stream. This may explain the differences in the GI values within and among the subjects in the present study. ...
... Inclusion of foods such as whole grains in our daily meals/diets has been suggested. Inclusion of whole cereal grains in the diets of diabetic subjects may assist in the dietary management by controlling diabetic complications [31]. While planning diet for diabetic therefore, low GI foods should be favorable, medium GI foods should be acceptable while high GI foods should be used only occasionally. ...
The glycemic index (GI) is a measure of the potential of foods containing the same amount of carbohydrate to raise ß-glucose concentration in the blood after a meal. This study was conducted to measure the glycemic index and glycemic load of staple foods used in Tanzania for the management of type 2 diabetes mellitus. Whole grain flours of maize, millet, cassava, dehulled white sorghum and green bananas mixed with sardines (sardinops malanosticta) were prepared into meals in the laboratory of the Department of Food Science and Technology, Sokoine University of Agriculture. Proximate composition of the flours was determined by using AOAC (1995) methods. Glycemic index (GI) was determined according to FAO/WHO (1998) recommendations using 10 respondents. Results showed that, cassava meal had the highest percentage of carbohydrate (83.31%) followed by sorghum (78.16%), maize (72.60%) finger millet (72.12%) and banana meal (17%). There was a significant (p<0.05) difference in carbohydrate content between cassava and the other foods. Regarding GI, results showed that, cassava diet had the lowest value (49.8) followed by maize (51), while banana (57.85) and finger millet (60.92) had medium GI values. Sorghum meal had the highest GI The variations in GI index values observed could be attributed to characteristics of the carbohydrate and the type of starch present in the foods. According to GIs data, the two test foods, cassava meal and undehulled maize meal are recommended for the regular diet for the management of type 2 diabetes mellitus. Moreover finger millet, sorghum and banana meals are also recommended to be consumed moderately in a diet. It is important to associate GL and GI data of Tanzanians traditional foods for the management and the prevention of diabetes in Tanzania and in others countries sharing the same tradition foods.
... Starch gelatinization, during baking, may be impaired by sugar competing for water, preventing gelatinization, and improving texture (Singh et al., 2003). Sugar is the generalized name for sweet, short-chain soluble carbohydrate, many of which are used in food (Mahgoub, Sabone, & Jackson, 2013). They are composed of Carbon, hydrogen, and Oxygen (Singh et al., 2003). ...
... The in vivo GI of the composite biscuits is presented in ( (Brouns et al., 2005). Glycemic indices of food have also been examined and reported in various studies conducted elsewhere in Africa (Foster-Powell et al., 2002;Mahgoub et al., 2013). More research is needed in a wide variety of countries to get population specific data necessary for guiding nutritionists, healthcare practitioners and consumers. ...
This study sought to investigate the sensory qualities, nutritional properties, and glycemic response of biscuits produced from pigeon pea (PP)—wheat flour (WF) in apparently healthy human subjects. Biscuits were produced by substituting WF with PP flour in the proportion of 100:0 (WF), 75:25 (PP‐25), 50:50 (PP‐50), 25:75 (PP‐75), and 0:100 (PP‐100) fortified with ginger (4.5%). Sensory evaluation revealed no significant difference (p < .05) between the biscuits in terms of aroma, color, and texture while a significant (p < .05) increase in taste and general acceptability was observed in (25% PP), and (WF) biscuits when compared to the PP composite biscuits. The results revealed that composite biscuits are rich in crude fiber, protein, and amylose, but have low glycemic index coupled with low sugar/starch and amylopectin. This suggests that PP supplementation in biscuit production may suggest a cheap and high‐quality substitute for WF in confectioneries.
Practical applications
This study provides valuable information on the possibility of using pigeon pea flour as high‐quality substitute for wheat flour in confectioneries. Additionally, the pigeon pea–wheat composite flour biscuits may possess good health promotion and disease preventing potentials. The data generated in this study may provide vital information on the process involved in formulating, planning, and utilizing the good quality pigeon pea–wheat composite flour in producing biscuits in food industries (Flour and baking industries).
... Additionally, the physiological relevance of the concentrations of sorghum extracts is uncertain, particularly regarding their capacity to elicit blood glucose-attenuating effects in humans at physiologically realistic doses. However, recent appraisals of the current evidence base confirm these favorable effects in adults with hyperglycemia (Abdelgadir et al., 2005;Lakshmi & Vimala, 1996;Mani et al., 1993;Prasad et al., 2015), as well as in normoglycemic adults (Anunciação et al., 2019;Mahgoub et al., 2013;Omoregie & Osagie, 2008;Poquette et al., 2014;Prasad et al., 2015;Stefoska-Needham et al., 2016. In this collection of studies, the glucose-attenuating effects were preserved to varying degrees following consumption of a wide range of foods (flatbreads, porridges, muffins, and breakfast cereals) that were manufactured using different processing methods. ...
Whole‐grain sorghum foods may elicit health‐promoting effects when consumed regularly in the diet. This review discusses key functional sorghum grain constituents, including dietary fiber, slowly digestible and resistant starches, lipids, and phytochemicals and their effects on metabolic processes that are associated with the development of chronic diseases, such as heart disease and diabetes. Currently, the range of sorghum food products available to consumers is limited globally, hindering the potential consumer benefits. A collaborative effort to innovate new product developments is therefore needed, with a focus on processing methods that help to retain the grain's favorable nutritive, health‐enhancing, and sensory attributes. Evidence for sorghum's purported health effects, together with evidence of impacts of processing on different sorghum foods, are presented in this review to fully elucidate the potential of sorghum grain to confer health benefits to humans.
... Most of the clinical trials on sorghum intake reported to date have been conducted in Africa [6,12,13], North, South America [5,7,9,14], Australia [8,[16][17], and India [18][19][20]. In these studies, sorghum has been shown to be effective in reducing blood glucose levels. ...
Background: Sorghum is consumed in Africa, North and South America, India, and other parts of the world, but it is one of several millets in Japan, and its physiological function for Japanese is not well known. In this study, we examined the effect of sorghum on postprandial blood glucose levels in healthy Japanese.Objective: This study aims to investigate the effect of sorghum intake on postprandial blood glucose in healthy adults. Methods: A double-blind crossover study was done on 17 healthy adult men and women recruited from the general population. After an early morning fasting blood glucose test, a placebo or sorghum porridge was administered and blood glucose levels were measured at 30, 60, and 120 minutes after the first washout period. Result: At 60 and 120 minutes after intake, the blood glucose level of people who were administered sorghum porridge was significantly lower than that of those who were administered the placebo. The area under the blood glucose curve was also significantly lower for the test product than for the placebo. Conclusion: Sorghum consumption can suppress the increase in postprandial blood glucose, suggesting that sorghum is useful in preventing the development of diabetes mellitus.Trial registration: UMIN-CTR: UMIN000046235Keywords: Sorghum, blood glucose, postprandial blood glucose
... Additionally, the protein present in sorghum is not bioavailable [40], and as a result, it may not produce the effect of delaying the digestion of the stiff porridge. This supports the high GI (>70) findings reported in Botswana for sorghumbased foods [57]. Contrary to these findings, a separate study has reported low to medium GI for some sorghum products [58]. ...
Background. The prevalence of diabetes mellitus is increasing worldwide. Knowledge of glycemic index (GI) is important in its prevention and management. The GI measures how rapidly or slowly the blood glucose increases after food consumption. Stiff porridge (ugali) is an African cuisine that can be prepared from various cereal grains and consumed alongside a relish, including milk. The impact of cereal grain type and milk on the GI of ugali is not understood. Objectives. To determine the GI of ugali prepared from maize, millet, and sorghum and establish the impact of fermented milk on the GI. Methods. Proximate composition was determined using the Association of Official Analytical Chemists methods. Moisture, fat, protein, ash, and crude fiber content were determined by oven drying, soxhlet, Kjeldahl, dry ashing, and Hennenberg and Stohmann methods, respectively. Carbohydrate content was determined by difference. The GI was determined using standard procedures (ISO 26642:2010). Blood sugar response curves were generated using Microsoft Excel software. The GI was computed by dividing the incremental area under the curve (IAUC) of test food by the IAUC of glucose and then multiplied by 100. Data were analyzed using GenStat 14th Edition software. Results. Maize ugali had significantly higher carbohydrate content as opposed to millet or sorghum ugali ( P < 0.05 ). The GI for plain ugali followed the order sorghum (72) > maize (67) > millet (46). When consumed alongside fermented milk, the GI order was maize (70) > millet (67) > sorghum (57). Conclusion. Millet-based ugali may be used in the management of diabetes. Fermented milk lowers the GI of sorghum ugali and increases the GI of maize and millet ugali.
... Unlike honey, this food has very low sugar content (1.44± 0.02g/100 DM) (Yeboué et al, 2017). Foods like amala (yam tuber, Dioscorea rotundata), agidi (maize food: Zea mays) and eba or garri (cassava tuber food: Manihot esculenta) studied by Omoregie and Osagie (2008) in Nigeria also had high GIs between 82 and 99 (Mahgoub et al., 2013). In Botswana, also a high GI of high carbohydrate was obtained for foods prepared from wheat (GI=103), maize (GI=91), sorghum (GI=92), millet (GI=95) and vegetables (GI= 86, morama food). ...
For characterizing the nutritional quality of two honeys from Côte d'Ivoire, a collection of 18 samples from the cities of Kouto (North) and Touba (West) was carried out during three periods. A biochemical analysis of the honeys was performed then the glycemic index (GI) and load (GL) of two samples, one from each locality was determined. The results indicate that these honeys were rich in total sugars (77.28 g/100g DM) and in reducing sugars (71.21 g/100g DM). They contained calcium (12.85 mg/100g DM), magnesium (17.61 mg/100g DM) and phosphorus (13.47 mg/100g DM). On average, they had an ash content of 0.30 g/100g DM, a titratable acidity of 56.1 mEq/Kg with an acid pH equal to 3, polyphenol contents of 60.39 mg/100gDM and flavonoids of 5.83 mg/100g DM. Kouto honey (50.74) was lower GI food than Touba honey (57.20). Nevertheless, these two honeys carry high glycemic loads. Given their high sugar content, these honeys could be high-risk foods for overweight and diabetic populations.
... Ces données sont d'une grande pertinence dans le contexte de la Côte d'Ivoire, où ce plat traditionnel est introduit dans les habitudes urbaines et est largement proposé sur les marchés [16]. D'après l'enquête bibliographique, plusieurs études similaires ont montré des valeurs d'IG élevées des produits amylacés traditionnels à base de plantain [6], [3], [22], [33]. Par ailleurs, bien que le meilleur rapport entre la pâte de plantain et la farine de céréales ait été de 90/10 % à l'optimisation des paramètres du procédé de fabrication du Dockounou [16], l'IG du Dockounou (optimisé ou non) n'a pas affecté dans la présente étude. ...
Des données récentes recueillies à partir de l'optimisation de la fabrication du gâteau dockounou ont montré qu'un dockounou optimisé pourrait être un excellent moyen de valorisation de la banane plantain trop mûre. Mais, à ce jour, il existe peu de données scientifiques sur les propriétés glycémiques de cet aliment, qui est intégré dans les habitudes alimentaires urbaines. Nous avons donc déterminé l'index glycémique et la charge glycémique d’un dockounou traditionnel et le dockounou optimisé. En outre, nous avons réalisé leur profilage glucidique, dont la présence dans ces mets n’a été que peu étudiée. Dans l'ensemble, il n'y a pas eu de variations considérables dans leur composition nutritionnelle, à l'exception des cendres et des glucides. Les valeurs suivantes ont été obtenues pour les composantes glucidiques (g/100 g): amidon (32,4-33,7); saccharose (4,1- 8,8); glucose (20,1-20,7); fructose (21,1-22,6); fibres solubles (2,5-2,5) et fibres insolubles (6,9-6,9). L’index glycémique et la charge glycémique étaient respectivement de 79 et 20,4 pour le dockounou optimisé et respectivement de 81 et 21,3 pour le dockounou
traditionnel. Ces résultats confirment bien que ces aliments sont une bonne source de glucides, notamment de la fraction glucose. Cependant, les niveaux élevés d'index glycémique et de charge glycémique impliquent une consommation avec modération.
... The high glycemic index (97.37%) of wheat in this study is similar to 95.80% and 95.28% reported for wheat semovita and wheat semolina in an earlier study (19). A study in Botswana study also reported a higher glycemic index for wheat-based foods as 103.1% (21). The differences in the glycemic index values may be attributed to cooking methods and ethnicity of the participants. ...
Background: Information on glycemic index of staple foods are required to develop appropriate nutrition education materials to promote informed food choices. Objective: This study was designed to determine the glycemic index of four Nigerian staple foods, namely pineapple, banana, jollof rice and wheat flour dough. Method: The study was descriptive cross-sectional in design. Ten apparently healthy postgraduate 2 students (4 males and 6 females, 25.8±2.0 years; BMI: 22.68±2.69 kg/m ; fasting blood sugar: 92.1±3.38 mg/dl) randomly consumed 50 g available carbohydrate portions of test foods and glucose over a five-day period. Blood samples were collected in the fasting state and half-hourly over a 2-h period post-ingestion of test and reference foods to determine plasma glucose concentrations, incremental area under the glucose curve, glycemic index and glycemic load. Results: A 50 g available carbohydrate is equivalent to 176 g of banana, 199 g of jollof rice, 229 g of wheat dough and 322 g of pineapple. The Incremental Area Under the Curve for jollof rice, wheat dough and pineapple showed no significant difference when compared with glucose, while of banana was significant at P<0.05 when compared with glucose. The glycemic index was 94.88%, 97.37%, 98.9% and 99.3% and the corresponding glycemic load was 47.43%, 48.69%, 50.47% and 50.67%, for pineapple, wheat flour, jollof rice and banana, respectively.
... The high glycemic index (97.37%) of wheat in this study is similar to 95.80% and 95.28% reported for wheat semovita and wheat semolina in an earlier study (19). A study in Botswana study also reported a higher glycemic index for wheat-based foods as 103.1% (21). The differences in the glycemic index values may be attributed to cooking methods and ethnicity of the participants. ...
Background: Information on glycemic index of staple foods are required to develop appropriate nutrition education materials to promote informed food choices. Objective: This study was designed to determine the glycemic index of four Nigerian staple foods, namely pineapple, banana, jollof rice and wheat flour dough. Method: The study was descriptive cross-sectional in design. Ten apparently healthy postgraduate 2 students (4 males and 6 females, 25.8±2.0 years; BMI: 22.68±2.69 kg/m ; fasting blood sugar: 92.1±3.38 mg/dl) randomly consumed 50 g available carbohydrate portions of test foods and glucose over a five-day period. Blood samples were collected in the fasting state and half-hourly over a 2-h period post-ingestion of test and reference foods to determine plasma glucose concentrations, incremental area under the glucose curve, glycemic index and glycemic load. Results: A 50 g available carbohydrate is equivalent to 176 g of banana, 199 g of jollof rice, 229 g of wheat dough and 322 g of pineapple. The Incremental Area Under the Curve for jollof rice, wheat dough and pineapple showed no significant difference when compared with glucose, while of banana was significant at P<0.05 when compared with glucose. The glycemic index was 94.88%, 97.37%, 98.9% and 99.3% and the corresponding glycemic load was 47.43%, 48.69%, 50.47% and 50.67%, for pineapple, wheat flour, jollof rice and banana, respectively.
... (2011), GI value is low if lower than 55. There is the porridge exhibit the lowest GI such as jumbo oats porridge from UK diet with GI < 55 (Aston et al., 2008) and red millet porridge mixed with kelen-kelen leaves and beans/peanuts of Koubala et al. (2014) (Mahgoub et al., 2013) while the GI of maize flour stiff porridges from Malawi has GI range between 70-120 (Mlotha et al., 2015). ...
Bubur pedas is the one of The Ethnic Malay Food from Sambas District and it has become a culinary icon of West Kalimantan, Indonesia. Up till now, there is no health information related to bubur pedas. The aim of the research is to evaluate the calories and glycaemic index (GI) in order to promote healthy porridge from West Kalimantan. Data were collected from a sampling survey in 5 bubur pedas cafe in Pontianak, descriptive and anova analyzed. The results showed that one serving size of bubur pedas (432g) has sufficient energy (618.11 kcal) and protein (7.13 g/person) for breakfast food. GI value of bubur pedas is low (<50). This study adds to the scientific evidence bubur pedas in Indonesia as one of the most popular culinary ethnics in West Kalimantan for years that should be safeguarded and conserved for its outstanding value not only for traditional porridge, but also for its intangible cultures.
... The results was different from corn or maize-based porridges in B ostwana and Malawi of Africa that exhibit the highest GI > 80. The GI of maize meal stiff porridge, soft porridge, stiff porridge, marami and sorghum/maize porridge from Bostwana has GI range between 87-93 (Mahgoub et al., 2013) while the GI of maize flour stiff porridges from Malawi has GI range between 70-120 (Mlotha et al., 2015). ...
Bubur pedas is the one of The Ethnic Malay Food from Sambas Distric and it has become a culinary icon of West Kalimantan, Indonesia. Up till now, there is no health information relat ed to bubur pedas. The aim of the research is to evaluate the calories and glycaemic index (GI) in order to promote the healthy porridge from West Kalimantan. Data was collected from sampling survey in 5 bubur pedas cafe in Pontianak, descriptive and anova analyzed. The results showed that one serving size of bubur pedas (432g) has sufficient energy (618.11 kcal) and protein (7.13 g/person) for a breakfast food. GI value of bubur pedas is low (< 50). This study adds to the scientific evidence bubur pedas in Indonesia as one of the most popular culinary ethnic in West Kalimantan for years that should be safeguarded and conserved for its outstanding value not only for t raditional porridge, but also for its intangible cultures.
... This would be a great relevance in the context of Côte d'Ivoire, where the pounded plantain is considered as a delicacy. From the literature survey, similar several studies showed high GI values of traditional starchy products [5]; [28]. As mentioned above, foutou banane is a food highly consumed in Côte d'Ivoire and the GLs calculated for tested plantain foods appear high (GL > 20) [26] because of the large serving-size (450 g) which is usually consumed per day (Table 3). ...
The rapid increase in diabetes incidence in Côte d’Ivoire indicates the need to evaluate the nutritional profile of foods. In this study, we performed a nutritional characterization and glycemic index/load (GI/GL) of pounded plantain, which is the predominant mode of banana consumption. Five groups of 13 apparently healthy subjects consumed in random order 5 experimental products variants and twice a glucose solution. Proximate composition was conducted by AOAC standard methods. The GI was obtained following ISO/FDI 26642:2010 protocol and the GL was calculated from test food’s GI, considering the amount of available carbohydrate in the
traditional portion size. Moisture of samples ranged from 55.8–70.9g/100g. Based on dry weight per 100 gram, the samples had 0.2-0.8g ash, 0.3-1.3g lipids, 3.5-10.5g protein, 1.8-1.9g crude fibre, 86.8-94.1g carbohydrates and 398.4-403.5kcal for energy. Excepted pounded plantain from agnrin variety at “green” stage of ripeness (GI 40), the corresponding GI values were high (GI 75-84). The GL values of the foods tested were also considered high, varying from 60 to 144. Data showed that pounded plantain is potentially a source of high GI/GL carbohydrate.
... This would be a great relevance in the context of Côte d'Ivoire, where the pounded plantain is considered as a delicacy. From the literature survey, similar several studies showed high GI values of traditional starchy products [5]; [28]. As mentioned above, foutou banane is a food highly consumed in Côte d'Ivoire and the GLs calculated for tested plantain foods appear high (GL > 20) [26] because of the large serving-size (450 g) which is usually consumed per day (Table 3). ...
... Glycemic indices of food have also been examined and reported in various studies conducted elsewhere in Africa (Foster-Powell et al. 2002;Mahgoub et al. 2013). Unfortunately, reported GI values vary widely across studies and cannot be used to guide diets for the region. ...
Glycemic index is defined as the incremental area under the blood glucose response curve of a 50 g carbohydrate portion of a test food expressed as a percent of the response to the same amount of carbohydrate from a standard food taken by the same subject. This study investigated glycemic index of maize stiff porridges consumed as staple food in Malawi and a large majority of other countries in sub-Saharan Africa to identify areas for improvement in consumer diets. Stiff porridges were prepared using flour from whole maize, maize grits, and fermented maize grits. The porridges were served to 11 healthy volunteers for 3 weeks, with two serving sessions a week. Glucose was served as a reference food during weekly serving sessions. Results from descriptive analysis revealed that glycemic responses varied across subjects and porridge types. Porridge prepared from fermented maize grits had moderate glycemic index of 65.49 and was comparable in nutrient composition and sensory characteristics with the other test porridges. Glycemic indices of the porridges prepared from whole maize flour and grits were high at 94.06 and 109.64, respectively, attributed to the effect of traditional maize flour processing, preparation, and cooking methods used. The study also calculated glyaemic load of the porridges and drew recommendations to inform diet planning and modifications for healthy and diabetic individuals.
... Similar foods like the amala (yam tuber: Dioscorea rotundata), agidi (maize: Zea mays) and eba/garri (cassava tuber: Manihot utilisima) studied by Omoregie and Osagie [28] in Nigeria had GI ranging from 82 to 99. Mahgoub et al. [29] in Botswana also found GIs of the key staple carbohydrate rich foods prepared from wheat (GI 103), maize (GI 91), sorghum (GI 92), millet (GI 95) and legumes (GI 86). Due to their high carbohydrate contents (80% dry weight) and the presence of gelatinised starch (gelatinisation is determined by free moisture), these foods have been capable of inducing significant glycaemia in normal serving sizes, contrary to attieke, which could be considered as a medium GI food (GI 55-69) [7]. ...
There is currently an increased global interest in the published glycaemic index (GI) and glycaemic load (GL) values of foods. However, data on the GI and GL values of different varieties of foods within Côte d'Ivoire are very limited. The study therefore aimed at finding the GI and GL of the main food staples in Côte d'Ivoire. Following the International Standard Organisation's protocol (ISO/FDI 26642:2010), a selection of five staple foodstuffs were tested for their GI and GL. Fasted healthy subjects were given 50 g of available carbohydrate servings of a glucose reference, which was tested twice, and test foods which were tested once, on separate occasions. Excepted attieke (GI 63), the majority of foods tested have a high GI (GI > 70). Attieke (agbodjama) had a high GL (GL 29) while placali (GL 17) and maize meal stiff porridge (GL 16) had medium GLs. The GLs of pounded cassava-plantain and pounded yam are 26 and 22. Consumption of attieke could minimize postprandial blood glucose spikes, in spite of high GL and potentially have benefit in the management and prevention of some chronic diseases.
Sorghum requires fewer inputs for sustainable cultivation in harsh climates and has the potential to be utilized in modern food product innovations. Moreover, consumption of sorghum may elicit favorable health effects similar to other commonly consumed cereals, like wheat. Animal and human research exploring health effects of sorghum consumption indicates potential beneficial effects on blood glucose and lipid regulation, oxidative stress modulation, appetite regulation and weight management. However, a recent appraisal of the strength of evidence has not been conducted. Therefore, this study aims to evaluate the effects of sorghum consumption on metabolic indicators of chronic disease, including blood lipid and blood glucose levels, markers of oxidative stress, and factors associated with weight management. Using CINAHL, Cochrane Library, PubMed and MEDLINE databases, a systematic review of intervention studies published up to May 2020 was conducted and 16 interventional studies met the criteria for inclusion. Evidence for favorable effects of sorghum consumption on indicators of chronic disease, including blood glucose responses, markers of oxidative stress, satiety measures and weight management was demonstrated. Evidence from this systematic review may assist to promote sorghum's potential health benefits globally, including in food markets where it is underutilized, stimulating more sorghum-based food innovations in the future.
This study evaluated the chemical composition and glycemic index (GI) of eight different types of traditional Omani breads made from wheat flour. Significant (P < 0.05) differences were observed in the proximate chemical composition, dietary fibre content, and gross energy value of these breads. The moisture, crude protein, total fat, ash, crude fibre and nitrogen free extract (NFE) contents ranged between 21.6–51.6, 4.3–10.5, 0.8–13.8, 1.2–2.3, 1.0–2.0, and 34.5–61.8 g/100 g of sample respectively. The values for dietary fibre were between 5.6, 9.6 g/100g, and the gross energy contents ranged between 897 and 1468 kJ/100 g. The GI value of these breads also differed significantly (P < 0.05). No significant differences were however observed among the GI values for White Toast Bread (local commercial bread), Brown Toast Bread (local commercial bread), White Khubz Lebanani (local commercial bread), Brown Khubz Lebanani (local commercial bread), and Chapati (local homemade bread), which were 63 ± 12, 58 ± 15, 63 ± 10, 57 ± 20, and 58 ± 10, respectively. Paratha (local restaurant made bread with fat), Goleh (local homemade soft bread), and Rekhal (local homemade thin bread) showed significantly (P < 0.05) lower GI values as compared to other breads, and these were 32 ± 13, 43 ± 13 and 39 ± 7, respectively. No specific correlation was observed in the chemical composition and glycemic index of these breads. These breads fall within low to medium GI category of foods.
To determine the glycemic index (GI) and glycemic load (GL) values of Chinese traditional foods in Hong Kong.
Fifteen healthy subjects (8 males and 7 females) volunteered to consume either glucose or one of 23 test foods after 10-14 h overnight fast. The blood glucose concentrations were analyzed immediately before, 15, 30, 45, 60, 90 and 120 min after food consumption using capillary blood samples. The GI value of each test food was calculated by expressing the incremental area under the blood glucose response curve (IAUC) value for the test food as a percentage of each subject's average IAUC value for the glucose. The GL value of each test food was calculated as the GI value of the food multiplied by the amount of the available carbohydrate in a usual portion size, divided by 100.
Among all the 23 Chinese traditional foods tested, 6 of them belonged to low GI foods (Tuna Fish Bun, Egg Tart, Green Bean Dessert, Chinese Herbal Jelly, Fried Rice Vermicelli in Singapore-style, and Spring Roll), 10 of them belonged to moderate GI foods (Baked Barbecued Pork Puff, Fried Fritter, "Mai-Lai" Cake, "Pineapple" Bun, Fried Rice Noodles with Sliced Beef, Barbecue Pork Bun, Moon Cakes, Glutinous Rice Ball, Instant Sweet Milky Bun, and Salted Meat Rice Dumpling), the others belonged to high GI foods (Fried Rice in Yangzhou-Style, Sticky Rice Wrapped in Lotus Leaf, Steamed Glutinous Rice Roll, Jam and Peanut Butter Toast, Plain Steamed Vermicelli Roll, Red Bean Dessert, and Frozen Sweet Milky Bun).
The GI and GL values for these Chinese traditional foods will provide some valuable information to both researchers and public on their food preference.
This study determined the glycemic index (GI) of selected carbohydrate-rich foods consumed in Qatar. Recruited volunteers (n = 19) consumed two reference foods, glucose and white bread, and 10 test foods. The foods tested for their GI were Fatayer (cheese, Zaatar, spinach), Tanour white bread, white basmati rice, Shearia, Muhalabea, Sago Awama and Qurs Aquili. Results of the study indicated that all of the foods tested had high GIs (> 70). Shearia had the highest GI (84.0 +/- 1.85) using the glucose scale, and Fatayer Spinach had the lowest GI (77.6 +/- 2.00). There was no significant correlation between the GI of all test foods, using glucose or white bread as standard foods, and the age or the body mass index of the volunteers (P > 0.05). The study provides data on the GIs of carbohydrate-based foods consumed in Qatar and other Arabian Gulf countries that have not been reported before.
The concept of glycemic index (GI) lists food items by virtue of their influence on postprandial glucose. Though the glycemic index of common food items has been determined, the GI of the popularly processed and commonly consumed foods in Nigeria is not known. This study determined the GI of ten processed Nigerian foods and revealed their similarity in the release of glucose on consumption. The food items tested were made from yam tubers, cassava tubers and local cereals. These foods were served to human volunteers in several processed forms which resulted in viscous pastes. The GI results are presented and it is recommended that these processed foods should be discouraged in the regular dietary plan of people with chronic diseases such as coronary heart diseases, diabetes and cancer.
Little is known about the effects of the amount and type of carbohydrates on risk of coronary heart disease (CHD).
The objective of this study was to prospectively evaluate the relations of the amount and type of carbohydrates with risk of CHD.
A cohort of 75521 women aged 38-63 y with no previous diagnosis of diabetes mellitus, myocardial infarction, angina, stroke, or other cardiovascular diseases in 1984 was followed for 10 y. Each participant's dietary glycemic load was calculated as a function of glycemic index, carbohydrate content, and frequency of intake of individual foods reported on a validated food-frequency questionnaire at baseline. All dietary variables were updated in 1986 and 1990.
During 10 y of follow-up (729472 person-years), 761 cases of CHD (208 fatal and 553 nonfatal) were documented. Dietary glycemic load was directly associated with risk of CHD after adjustment for age, smoking status, total energy intake, and other coronary disease risk factors. The relative risks from the lowest to highest quintiles of glycemic load were 1.00, 1.01, 1. 25, 1.51, and 1.98 (95% CI: 1.41, 2.77 for the highest quintile; P for trend < 0.0001). Carbohydrate classified by glycemic index, as opposed to its traditional classification as either simple or complex, was a better predictor of CHD risk. The association between dietary glycemic load and CHD risk was most evident among women with body weights above average ¿ie, body mass index (in kg/m(2)) >/= 23.
These epidemiologic data suggest that a high dietary glycemic load from refined carbohydrates increases the risk of CHD, independent of known coronary disease risk factors.
Accumulating data indicate that a diet characterized by low glycaemic-index (GI) foods not only improves certain metabolic ramifications of insulin resistance, but also reduces insulin resistance per se. Epidemiological data also suggest a protective role against development of non-insulin-dependent diabetes mellitus and cardiovascular disease. A major disadvantage in this connection is the shortage of low-GI foods, and many common starchy staple foods, such as bread products, breakfast cereals and potato products, have a high GI. Studies in our laboratory show that it is possible to significantly lower the GI of starchy foods, for example by choice of raw material and/or by optimizing the processing conditions. Such low-GI foods may or may not influence glucose tolerance at a subsequent meal. Consequently, certain low-GI breakfasts capable of maintaining a net increment in blood glucose and insulin at the time of the next meal significantly reduced post-prandial glycaemia and insulinaemia following a standardized lunch meal, whereas others had no 'second-meal' impact. These results imply that certain low-GI foods may be more efficient in modulating metabolism in the long term. Although the literature supports a linear correlation between the GI and insulinaemic index (II) of foods, this is not always the case. Consequently, milk products elicited elevated IIs, indistinguishable from a white bread reference meal, despite GIs in the lower range. This inconsistent behaviour of milk products has not been acknowledged, and potential metabolic consequences remain to be elucidated.
Foods with a low glycemic index are increasingly being acknowledged as beneficial in relation to the insulin resistance syndrome. Certain organic acids can lower the glycemic index of bread products. However, the possible effect of acids in fermented milk products on the glycemic index and on insulinemic characteristics has not been addressed. The metabolic effects of fermented milk or pickled products used as additives to mixed meals have also not been addressed.
One objective was to characterize the glycemic and insulinemic responses after intake of regular or fermented milk products (study 1). In addition, the acute metabolic effect of fermented milk (yogurt) and pickled cucumber as supplements to a traditional breakfast based on a high-glycemic index bread was evaluated (study 2).
Ten healthy volunteers were served different breakfast meals after an overnight fast. Capillary blood samples were collected before and during 2 (study 1) or 3 (study 2) h after the meal. White-wheat bread was used as a reference meal in both studies.
The lactic acid in the fermented milk products did not lower the glycemic and insulinemic indexes. Despite low glycemic indexes of 15-30, all of the milk products produced high insulinemic indexes of 90-98, which were not significantly different from the insulinemic index of the reference bread. Addition of fermented milk (yogurt) and pickled cucumber to a breakfast with a high-glycemic index bread significantly lowered postprandial glycemia and insulinemia compared with the reference meal. In contrast, addition of regular milk and fresh cucumber had no favorable effect on the metabolic responses.
Milk products appear insulinotropic as judged from 3-fold to 6-fold higher insulinemic indexes than expected from the corresponding glycemic indexes. The presence of organic acids may counteract the insulinotropic effect of milk in mixed meals.
Reliable tables of glycemic index (GI) compiled from the scientific literature are instrumental in improving the quality of research examining the relation between GI, glycemic load, and health. The GI has proven to be a more useful nutritional concept than is the chemical classification of carbohydrate (as simple or complex, as sugars or starches, or as available or unavailable), permitting new insights into the relation between the physiologic effects of carbohydrate-rich foods and health. Several prospective observational studies have shown that the chronic consumption of a diet with a high glycemic load (GI x dietary carbohydrate content) is independently associated with an increased risk of developing type 2 diabetes, cardiovascular disease, and certain cancers. This revised table contains almost 3 times the number of foods listed in the original table (first published in this Journal in 1995) and contains nearly 1300 data entries derived from published and unpublished verified sources, representing > 750 different types of foods tested with the use of standard methods. The revised table also lists the glycemic load associated with the consumption of specified serving sizes of different foods.
Low glycemic index (LGI) diets have been shown to improve glucose tolerance in clinical studies; however, this does not necessarily ensure similar effectiveness when given to free-living individuals making their own food choices. This concern was reflected in the current position of the American Diabetes Association (1) in that “although LGI foods may reduce postprandial hyperglycemia, there is insufficient evidence of long-term benefits to recommend general use of LGI diets in type 2 diabetic patients.” Despite this, the glycemic index (GI) method for classifying carbohydrates has been endorsed by a number of influential bodies, including the Food and Agriculture Organization of the United Nations/World Health Organization …
Practical use of the glycaemic index (GI), as recommended by the FAO/WHO, requires an evaluation of the recommended method. Our purpose was to determine the magnitude and sources of variation of the GI values obtained by experienced investigators in different international centres.
GI values of four centrally provided foods (instant potato, rice, spaghetti and barley) and locally obtained white bread were determined in 8-12 subjects in each of seven centres using the method recommended by FAO/WHO. Data analysis was performed centrally.
University departments of nutrition.
Healthy subjects (28 male, 40 female) were studied.
The GI values of the five foods did not vary significantly in different centres nor was there a significant centrexfood interaction. Within-subject variation from two centres using venous blood was twice that from five centres using capillary blood. The s.d. of centre mean GI values was reduced from 10.6 (range 6.8-12.8) to 9.0 (range 4.8-12.6) by excluding venous blood data. GI values were not significantly related to differences in method of glucose measurement or subject characteristics (age, sex, BMI, ethnicity or absolute glycaemic response). GI values for locally obtained bread were no more variable than those for centrally provided foods.
The GI values of foods are more precisely determined using capillary than venous blood sampling, with mean between-laboratory s.d. of approximately 9.0. Finding ways to reduce within-subject variation of glycaemic responses may be the most effective strategy to improve the precision of measurement of GI values.
The applicability of the glycaemic index (GI) in the context of mixed meals and diets is still debatable. The objective of the present study was to investigate the predictability of measured GI in composite breakfast meals when calculated from table values, and to develop prediction equations using meal components. Furthermore, we aimed to study the relationship between GI and insulinaemic index (II). The study was a randomised cross-over meal test including twenty-eight healthy young men. Thirteen breakfast meals and a reference meal were tested. All meals contained 50 g available carbohydrate, but differed considerably in energy and macronutrient composition. Venous blood was sampled for 2 h and analysed for glucose and insulin. Prediction equations were made by regression analysis. No association was found between predicted and measured GI. The meal content of energy and fat was inversely associated with GI (R(2) 0.93 and 0.88, respectively; P<0.001). Carbohydrate content (expressed as percentage of energy) was positively related to GI (R(2) 0.80; P<0.001). Using multivariate analysis the GI of meals was best predicted by fat and protein contents (R(2) 0.93; P<0.001). There was no association between GI and II. In conclusion, the present results show that the GI of mixed meals calculated by table values does not predict the measured GI and furthermore that carbohydrates do not play the most important role for GI in mixed breakfast meals. Our prediction models show that the GI of mixed meals is more strongly correlated either with fat and protein content, or with energy content, than with carbohydrate content alone. Furthermore, GI was not correlated with II.
Regulation of blood glucose to achieve near-normal levels is a primary goal in the management of diabetes, and, thus, dietary techniques that limit hyperglycemia following a meal are likely important in limiting the complications of diabetes. Low-carbohydrate diets are not recommended in the management of diabetes. Although dietary carbohydrate is the major contributor to postprandial glucose concentration, it is an important source of energy, water-soluble vitamins and minerals, and fiber. Thus, in agreement with the National Academy of Sciences-Food and Nutrition Board, a recommended range of carbohydrate intake is 45-65% of total calories. In addition, because the brain and central nervous system have an absolute requirement for glucose as an energy source, restricting total carbohydrate to < 130 g/day is not recommended. Both the amount (grams) of carbohydrate as well as the type of carbohydrate in a food influence blood glucose level. The total amount of carbohydrate consumed is a strong predictor of glycemic response, and, thus, monitoring total grams of carbohydrate, whether by use of exchanges or carbohydrate counting, remains a key strategy in achieving glycemic control. A recent analysis of the randomized controlled trials that have examined the efficacy of the glycemic index on overall blood glucose control indicates that the use of this technique can provide an additional benefit over that observed when total carbohydrate is considered alone. Although this statement has focused primarily on the role of carbohydrate in the diet, the importance of achieving/ maintaining a healthy body weight (particularly in type 2 diabetes) in the management of diabetes should not be ignored. Moderate weight loss in overweight/obese individuals with type 2 diabetes results in improved control of hyperglycemia as well as in a reduction in risk factors for cardiovascular disease. Because much of the risk of developing type 2 diabetes is attributable to obesity, maintenance of a healthy body weight is strongly recommended as a means of preventing this disease. The relationship between glycemic index and glycemic load and the development of type 2 diabetes remains unclear at this time.
Introduction and objective. The glycaemic index (GI) can be determined using capillary blood or venous plasma sampling. The aim of this study was to compare the GIs of three South African oat products determined using both capillary blood and venous plasma. Methods. Twenty healthy, non-smoking male students (mean age 21.0 years, standard deviation (SD) 1.28 years, mean body mass index (BMI) 24.55, SD 2.62) volunteered to participate. Each subject received a standard pretest meal the evening before test days. The reference food used was glucose, and the test meals were three oat porridges, namely Jungle oats (66 g dry weight), Bokomo oats (72.8 g) and Oatso Easy (101 g) in the form they are normally consumed, namely with milk (150 ml) and sugar (20 g), or water only in the case of Oatso Easy, an instant porridge. Each meal contained 50 g glycaemic carbohydrate as determined by the Englyst method. Capillary blood glucose and venous blood samples were taken simultaneously at 0, 15, 30, 45, 60, 90 and 120 minutes and areas under the curve (AUC) and GI were calculated. Results. The mean fasting glucose value obtained from venous plasma before all tests (N = 80) was significantly lower (4.5 mmol/l, SD 0.7, p < 0.002) than the mean capillary blood glucose concentration (4.8 mmol/l, SD 0.04). The mean incremental AUCs obtained from venous plasma after all test meals and the reference (oral glucose) differed significantly (p < 0.01) from the AUCs obtained from capillary blood. The SDs for GIs calculated from venous plasma samples were at least 3 times larger than the SDs for GIs calculated from capillary samples. No significant differences were found between the GIs of the three oat products. Conclusion. The present data are consistent with previous results showing that glycaemic responses measured in venous plasma are lower and more variable than those in simultaneously obtained capillary blood. The most precise and accurate determination of GI may be achieved using capillary rather than venous blood sampling, supporting the recommendation of the working group on the standardisation of GI testing in South Africa.
Objective.
—To examine prospectively the relationship between glycemic diets, low fiber intake, and risk of non—insulin-dependent diabetes mellitus.Desing.
—Cohort study.Setting.
—In 1986, a total of 65173 US women 40 to 65 years of age and free from diagnosed cardiovascular disease, cancer, and diabetes completed a detailed dietary questionnaire from which we calculated usual intake of total and specific sources of dietary fiber, dietary glycemic index, and glycemic load.Main Outcome Measure.
—Non—insulin-dependent diabetes mellitus.Results.
—During 6 years of follow-up, 915 incident cases of diabetes were documented. The dietary glycemic index was positively associated with risk of diabetes after adjustment for age, body mass index, smoking, physical activity, family history of diabetes, alcohol and cereal fiber intake, and total energy intake. Comparing the highest with the lowest quintile, the relative risk (RR) of diabetes was 1.37 (95% confidence interval [CI], 1.09-1.71, Ptrend=.005). The glycemic load (an indicator of a global dietary insulin demand) was also positively associated with diabetes (RR=1.47; 95% CI, 1.16-1.86, Ptrend=.003). Cereal fiber intake was inversely associated with risk of diabetes when comparing the extreme quintiles (RR=0.72,95% CI, 0.58-0.90, Ptrend=.001). The combination of a high glycemic load and a low cereal fiber intake further increased the risk of diabetes (RR=2.50, 95% CI, 1.14-5.51) when compared with a low glycemic load and high cereal fiber intake.Conclusions.
—Our results support the hypothesis that diets with a high glycemic load and a low cereal fiber content increase risk of diabetes in women. Further, they suggest that grains should be consumed in a minimally refined form to reduce the incidence of diabetes.
Potato is a food which yields very variable glycemic responses. It makes a major contribution to total starch intake and the share of processed potato products is growing. The aim of the study was to determine the effects of processing and storage on the glycemic indices (GIs) of industrially processed potato products.Two groups (11 and 10 volunteer subjects) attended a glucose tolerance test and glycemic response test of 4 and 3 processed potato products, respectively. GIs of different potato products were calculated for each subject using their own glucose tolerance test and glycemic responses for test meals and averages calculated for each product.GIs of freshly prepared potato products were high: steam boiled potatoes 104±39, oven-baked casserole 95±30 (carbo-peeled sliced potato) and mashed potatoes 106±42. GIs of cooled and cold stored potato products were intermediate, potato cubes served cold 76±32 and cooled, reheated oven-baked casseroles 73±25 (carbo-peeled sliced potato), 75±17 (carbo-peeled mashed potato) and 81±28 (steam-peeled mashed potato). Cooling and cold storage decreased GIs significantly (steam boiled potatoes vs. steam boiled potato cubes (P=0.01), freshly served casserole made of sliced potatoes vs. casserole cooled, cold stored and reheated P=0.01).Conclusion
Cooking method, peeling method, or slicing or mashing did not affect the GIs. Cooling and cold storage, despite reheating, lowered GIs of potato products by about 25%.
Countries of English-speaking Caribbean in the last thirty years have experienced an unprecedented epidemiological transition. Malnutrition in children and infectious diseases, once the major public health problems, have considerably declined and have been replaced by obesity and chronic noncommunicable diseases such as diabetes, hypertension, stroke, coronary heart disease and cancers. Countries of the Caribbean are net importers of food. During this period of time total food availability has greatly improved but from health point of view this improvement is highly skewed. The increase in the availability of total calories has been almost entirely due to increase in total fat, most of which is from foods from animal sources. While cereals are adequately available, none of the countries meets the recommended population goals for fruits, vegetables, roots, tubers and legumes and they lack upwards of fifty per cent of their needs. Indeed, an ecological study of food availability and disease pattern clearly shows a significant positive relationship between the increase in total calories and diabetes, and between total fat and coronary heart disease and cancers of prostate, breast and colon. A significant inverse relationship can also be noticed between consumption of roots, tubers, fruits and vegetables and heart disease and colorectal cancer. An important feature of this rapid transition in the Caribbean is that the complex problem of obesity and chronic diseases has followed right on the heels of nutritional deficiencies and infectious diseases. During this period of time, economies have not improved much, and almost all countries have incurred massive external debt and are reeling under economic structural adjustment programs. Although very much reduced, the threat of undernutrition and infectious diseases is still lurking in the background and may erupt into epidemic proportions under the fragile economic systems. Thus these countries are finding themselves torn between holding the reins of nutritional deficiencies and infectious diseases from resurfacing and making a frontal attack on the so called “diseases of affluence” with the resources only of developing countries. While eating properly is an individual choice, a variety of factors influence the choice. This paper suggests a series of strategies for appropriate policy development, private sector involvement, health care restructuring and public education programs.
The incidence of diabetes is very low in rural, traditionally living, South African Black people, but higher in the urbanised Black population. One factor, that could have contributed to the increased prevalence of diabetes, is the change in diet from maize porridge to bread. An in vitro method was used to determine the starch digestibility of African maize porridge compared to other cereal foods. Maize porridge had a much lower in vitro starch digestibility than white bread (P<0.001). There was a positive correlation (P=0.05) between rate of starch digestibility of maize porridge and endosperm hardness. Decreasing the particle size of the maize meal by conversion to maize flour did not increase starch digestibility. Both decreasing and increasing the cooking time decreased the starch digestibility. The predicted glycaemic index for maize porridge ranged from 39 to 50 (glucose standard), which suggests that maize porridge may be useful in the dietary management of diabetes.
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.
This study was carried out to determine the blood glucose response and glycaemic index (GI) values of four types of commercially available breads in Malaysia. Twelve healthy volunteers (six men, six women; body mass index, 21.9±1.6 kg/m(2); age, 22.9±1.7 years) participated in this study. The breads tested were multi-grains bread (M-Grains), wholemeal bread (WM), wholemeal bread with oatmeal (WM-Oat) and white bread (WB). The subjects were studied on seven different occasions (four tests for the tested breads and three repeated tests of the reference food) after an overnight fast. Capillary blood samples were taken immediately before (0 min) and 15, 30, 45, 60, 90 and 120 min after consumption of the test foods. The blood glucose response was obtained by calculating the incremental area under the curve. The GI values were determined according to the standardized methodology. Our results showed that the M-Grains and WM-Oat could be categorized as intermediate GI while the WM and WB breads were high GI foods, respectively. The GI of M-Grains (56±6.2) and WM-Oat (67±6.9) were significantly lower than the reference food (glucose; GI = 100) (P < 0.05). No significant difference in GI value was seen between the reference food and the GI of WM (85±5.9) and WB (82±6.5) (P > 0.05). Among the tested breads, the GI values of M-Grains and WM-Oat were significantly lower (P < 0.05) than those of WM and WB. There was no relationship between the dietary fibre content of the bread with the incremental area under the curve (r = 0.15, P = 0.15) or their GI values (r = 0.17, P = 0.12), indicating that the GI value of the test breads were unaffected by the fibre content of the breads. The result of this study will provide useful nutritional information for dieticians and the public alike who may prefer low-GI over high-GI foods.
There is controversy regarding the clinical utility of classifying foods according to their glycemic responses by using the glycemic index (GI). Part of the controversy is due to methodologic variables that can markedly affect the interpretation of glycemic responses and the GI values obtained. Recent studies support the clinical utility of the GI. Within limits determined by the expected GI difference and by the day-to-day variation of glycemic responses, the GI predicts the ranking of the glycemic potential of different meals in individual subjects. In long-term trials, low-GI diets result in modest improvements in overall blood glucose control in patients with insulin-dependent and non-insulin-dependent diabetes. Of perhaps greater therapeutic importance is the ability of low-GI diets to reduce insulin secretion and lower blood lipid concentrations in patients with hypertriglyceridemia.
Different starchy foods produce different glycemic responses when fed individually, and there is evidence that this also applies in the context of the mixed meal. Methods of processing, and other factors unrelated to the nutrient composition of foods may also have major effects on the glycemic response. The reason for differences in glycemic response appears to relate to the rate at which the foods are digested and the many factors influencing this. The glycemic index (GI) is a system of classification in which the glycemic responses of foods are indexed against a standard (white bread). This allows the results of different investigators to be pooled. GI values also depend upon a number of nonfood-related variables. The method of calculation of the glycemic response area is most important, but the method of blood sampling and length of time of studies also may have effects. Variability of glycemic responses arises from day-to-day variation in the same subject and variation between different subjects. There is less variability between the GI values of different subjects than there is within the same subject from day to day. Therefore, the mean GI values of foods are independent of the glucose tolerance status of the subjects being tested. Potentially clinically useful starchy foods producing relatively flat glycemic responses have been identified, including legumes, pasta, barley, bulgur, parboiled rice and whole grain breads such as pumpernickel. Specific incorporation of these foods into diets have been associated with reduced blood glucose, insulin, and lipid levels. Low-GI foods may influence amino acid metabolism although the implications of these are unknown. In addition, low GI foods increase colonic fermentation. The physiologic and metabolic implications of this relate to increased bacterial urea utilization, and to the production and absorption of short chain fatty acids in the colon. The application of the GI to therapeutic diets should be in the context of the overall nutrient composition of the diet. High-fat or high-sugar foods may have a low GI, but it may not be prudent to recommend these foods solely on the basis of the GI. It is therefore suggested that the most appropriate use of the GI is to rank the glycemic effects of starchy foods which would already have been chosen for possible inclusion in the diet on the basis of their nutritional attributes, i.e. low-fat, unrefined carbohydrate.
To review the evidence for the importance of glycaemic index of dietary carbohydrate in disease prevention and control.
A critical appraisal of the literature published in English between and cited on Medline between January 1966 and October 1999.
Using basic, intervention and epidemiological studies from experienced teams, evidence that the glycaemic index of diet may influence outcome in terms of cardiovascular risk, risk of metabolic syndrome diseases and pregnancy was found.
Consideration of glycaemic indices in making dietary recommendations may be expected to produce additional health benefit.
Dietary glycemic index, an indicator of the ability of the carbohydrate to raise blood glucose levels, and glycemic load, the product of glycemic index and carbohydrate intake, have been positively related to risk of coronary heart disease. However, the relationships between glycemic index and glycemic load and high-density lipoprotein cholesterol (HDL-C) concentration in the US population are unknown.
Using data from 13 907 participants aged 20 years and older in the Third National Health and Nutrition Examination Survey (1988-1994), we examined the relationships between glycemic index and glycemic load, which were determined from a food frequency questionnaire and HDL-C concentration.
The age-adjusted mean HDL-C concentrations for increasing quintiles of glycemic index distribution were 1.38, 1.32, 1.30, 1.26, and 1.27 mmol/L (P<.001 for trend). (To convert millimoles per liter to milligrams per deciliter, divide by 0.0259.) After additional adjustment for sex, ethnicity, education, smoking status, body mass index, alcohol intake, physical activity, energy fraction from carbohydrates and fat, and total energy intake, the mean HDL-C concentrations for ascending quintiles of glycemic index were 1.36, 1.31, 1.30, 1.27, and 1.28 mmol/L (P<.001 for trend). Adjusting for the same covariates and considering glycemic index as a continuous variable, we found a change in HDL-C concentration of -0.06 mmol/L per 15-unit increase in glycemic index (P<.001). The multiple R(2) for the model was 0.23. Similarly, the multivariate-adjusted mean HDL-C concentrations for ascending quintiles of glycemic load distribution were 1.35, 1.31, 1.31, 1.30, and 1.26 mmol/L (P<.001 for linear trend). The inverse relationships between glycemic index and glycemic load and HDL-C persisted across all subgroups of participants categorized by sex or body mass index.
These findings from a nationally representative sample of US adults suggest that high dietary glycemic index and high glycemic load are associated with a lower concentration of plasma HDL-C.
Controversy exists about the optimal amount and source of dietary carbohydrate for managing insulin resistance. Therefore, we compared the effects on insulin sensitivity (SI), pancreatic responsivity (AIRglu) and glucose disposition index of dietary advice aimed at reducing the amount or altering the source of dietary carbohydrate in subjects with impaired glucose tolerance (IGT). Subjects were randomized to high-carbohydrate-high-glycaemic index (GI) (high-GI, n 11), high-carbohydrate-low-GI (low-GI, n 13), or low-carbohydrate-high-monounsaturated fat (MUFA, n 11) dietary advice, with SI, AIRglu and DI measured using a frequently sampled, intravenous glucose tolerance test before and after 4 months treatment. Carbohydrate and fat intakes and diet GI, respectively, were: high-GI, 53 %, 28 %, 83; low-GI, 55 %, 25 %, 76; MUFA, 47 %, 35 %, 82. Weight changes on each diet differed significantly from each other: high-GI, -0.49 (sem 0.29) kg; low-GI, -0.19 (sem 0.40) kg; MUFA +0.27 (sem 0.45) kg. Blood lipids did not change, but glycated haemoglobin increased significantly on MUFA, 0.02 (sem 0.11) %, relative to low-GI, -0.19 (sem 0.08) %, and high-GI, -0.13 (sem 0.14) %. Diastolic blood pressure fell by 8 mmHg on low-GI relative to MUFA (P=0.038). Although SI and AIRglu did not change significantly, DI, a measure of the ability of beta-cells to overcome insulin resistance by increasing insulin secretion, increased on low-GI by >50 % (P=0.02). After adjusting for baseline values, the increase in DI on low-GI, 0.17 (sem 0.07), was significantly greater than those on MUFA, -0.09 (sem 0.08) and high-GI, -0.03 (sem 0.02) (P=0.019). Thus, the long-term effects of altering the source of dietary carbohydrate differ from those of altering the amount. High-carbohydrate-low-GI dietary advice improved beta-cell function in subjects with IGT, and may, therefore, be useful in the management of IGT.
Dietary glycemic load, the mathematical product of the glycemic index (GI) of a food and its carbohydrate content, has been proposed as an indicator of the glucose response and insulin demand induced by a serving of food. To validate this concept in vivo, we tested the hypotheses that 1). portions of different foods with the same glycemic load produce similar glycemic responses; and 2). stepwise increases in glycemic load for a range of foods produce proportional increases in glycemia and insulinemia. In the first study, 10 healthy subjects consumed 10 different foods in random order in amounts calculated to have the same glycemic load as one slice of white bread. Capillary blood samples were taken at regular intervals over the next 2 h. The glycemic response as determined by area under the curve was not different from that of white bread for nine foods. However, lentils produced lower than predicted responses (P < 0.05). In the second study, another group of subjects was tested to determine the effects of increasing glycemic load using a balanced 5 x 5 Greco-Latin square design balanced for four variables: subject, dose, food and order. Two sets of five foods were consumed at five different glycemic loads (doses) equivalent to one, two, three, four and six slices of bread. Stepwise increases in glycemic load produced significant and predictable increases in both glycemia (P < 0.001) and insulinemia (P < 0.001). These findings support the concept of dietary glycemic load as a measure of overall glycemic response and insulin demand.
High-carbohydrate, low-glycaemic index dietary advice improves glucose disposition index in subjects with impaired glucose tolerance
- Tms Wolever
- C Mehling
The role of carbohydrate in insulin resistance
- D H Bessenen