RESUMEN
BACKGROUND AND AIMS: The positive and negative health effects of dietary carbohydrates are of interest to both researchers and consumers. METHODS: 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). RESULTS: 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. CONCLUSIONS: 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.
Asunto(s)
Enfermedades Cardiovasculares/epidemiología , Diabetes Mellitus Tipo 2/epidemiología , Índice Glucémico , Carga Glucémica , Neoplasias/epidemiología , Glucemia/metabolismo , Peso Corporal , Enfermedades Cardiovasculares/dietoterapia , Diabetes Mellitus Tipo 2/dietoterapia , Dieta Mediterránea , Carbohidratos de la Dieta/administración & dosificación , Fibras de la Dieta/administración & dosificación , Humanos , Resistencia a la Insulina , Italia/epidemiología , Neoplasias/dietoterapia , Periodo Posprandial , Prevalencia , Factores de Riesgo , Granos EnterosRESUMEN
BACKGROUND: Short-chain fatty acids (SCFA) are produced by colonic microbiota from dietary carbohydrates and proteins that reach the colon. It has been suggested that SCFA may promote obesity via increased colonic energy availability. Recent studies suggest obese humans have higher faecal SCFA than lean, but it is unclear whether this difference is due to increased SCFA production or reduced absorption. OBJECTIVES: To compare rectal SCFA absorption, dietary intake and faecal microbial profile in lean (LN) versus overweight and obese (OWO) individuals. DESIGN: Eleven LN and eleven OWO individuals completed a 3-day diet record, provided a fresh faecal sample and had SCFA absorption measured using the rectal dialysis bag method. The procedures were repeated after 2 weeks. RESULTS: Age-adjusted faecal SCFA concentration was significantly higher in OWO than LN individuals (81.3±7.4 vs 64.1±10.4 mmol kg(-1), P=0.023). SCFA absorption (24.4±0.8% vs 24.7±1.2%, respectively, P=0.787) and dietary intakes were similar between the groups, except for a higher fat intake in OWO individuals. However, fat intake did not correlate with SCFAs or bacterial abundance. OWO individuals had higher relative Firmicutes abundance (83.1±4.1 vs 69.5±5.8%, respectively, P=0.008) and a higher Firmicutes:Bacteriodetes ratio (P=0.023) than LN individuals. There was a positive correlation between Firmicutes and faecal SCFA within the whole group (r=0.507, P=0.044), with a stronger correlation after adjusting for available carbohydrate (r=0.615, P=0.005). CONCLUSIONS: The higher faecal SCFA in OWO individuals is not because of differences in SCFA absorption or diet. Our results are consistent with the hypothesis that OWO individuals produce more colonic SCFA than LN individuals because of differences in colonic microbiota. However, further studies are needed to prove this.
Asunto(s)
Colon/metabolismo , Ácidos Grasos Volátiles/metabolismo , Heces/microbiología , Sobrepeso/metabolismo , Delgadez/metabolismo , Adulto , Colon/microbiología , Dieta , Registros de Dieta , Carbohidratos de la Dieta/metabolismo , Grasas de la Dieta/metabolismo , Femenino , Humanos , Masculino , Sobrepeso/microbiología , Proyectos Piloto , Absorción Rectal , Delgadez/microbiologíaRESUMEN
BACKGROUND AND AIMS: Nutrition recommendations for type 2 diabetes (T2DM) are partly guided by the postprandial responses elicited by diets varying in carbohydrate (CHO). We aimed to explore whether long-term changes in postprandial responses on low-glycemic-index (GI) or low-CHO diets were due to acute or chronic effects in T2DM. METHODS AND RESULTS: Subjects with diet-alone-treated T2DM were randomly assigned to high-CHO/high-GI (H), high-CHO/low-GI (L), or low-CHO/high-monounsaturated-fat (M) diets for 12-months. At week-0 (Baseline) postprandial responses after H-meals (55% CHO, GI = 61) were measured from 0800 h to 1600 h. After 12 mo subjects were randomly assigned to H-meals or study diet meals (L, 57% CHO, GI = 50; M, 44% CHO, GI = 61). This yielded 5 groups: H diet with H-meals (HH, n = 34); L diet with H- (LH, n = 17) or L-meals (LL, n = 16); and M diet with H- (MH, n = 18) or M meals (MM, n = 19). Postprandial glucose fluctuations were lower in LL than all other groups (p < 0.001). Changes in postprandial-triglycerides differed among groups (p < 0.001). After 12 mo in HH and MM both fasting- and postprandial-triglycerides were similar to Baseline while in MH postprandial-triglycerides were significantly higher than at Baseline (p = 0.028). In LH, triglycerides were consistently (0.18-0.34 mmol/L) higher than Baseline throughout the day, while in LL the difference from Baseline varied across the day from 0.04 to 0.36 mmol/L (p < 0.001). CONCLUSION: Low-GI and low-CHO diets have both acute and chronic effects on postprandial glucose and triglycerides in T2DM subjects. Thus, the composition of the acute test-meal and the habitual diet should be considered when interpreting the nutritional implications of different postprandial responses.
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Glucemia/análisis , Diabetes Mellitus Tipo 2/dietoterapia , Carbohidratos de la Dieta/administración & dosificación , Triglicéridos/sangre , Adulto , Anciano , Canadá , Dieta , Ácidos Grasos Monoinsaturados/sangre , Femenino , Índice Glucémico , Humanos , Insulina/sangre , Masculino , Persona de Mediana Edad , Periodo PosprandialRESUMEN
AIMS: Traditional lipid indices have been associated with type 2 diabetes, but limited data are available regarding non-high-density lipoprotein (non-HDL) cholesterol. In view of recent guidelines for the clinical management of dyslipidemia recommending the monitoring of non-HDL cholesterol as a secondary target after achieving the low-density lipoprotein (LDL) cholesterol goal, we aimed to assess the association of non-HDL cholesterol with incident type 2 diabetes and compare its utility as a risk predictor with traditional lipid variables in Aboriginal Canadians. METHODS: Of 606 diabetes-free participants at baseline, 540 (89.1%) returned for 10-year follow-up assessments. Baseline anthropometry, blood pressure, fasting insulin and serum lipids were measured. Fasting and 2-h postload glucose were obtained at baseline and follow-up to determine the incidence of type 2 diabetes. RESULTS: The cumulative incidence of type 2 diabetes was 17.5%. Higher non-HDL cholesterol, total-to-HDL cholesterol ratio, apolipoprotein B, triglyceride and LDL cholesterol and lower HDL cholesterol concentrations were individually associated with incident type 2 diabetes in univariate analyses (all p < 0.05). Non-HDL cholesterol was a superior determinant of incident diabetes compared with LDL cholesterol (comparing C-statistics of univariate models p = 0.01) or HDL cholesterol (p = 0.004). With multivariate adjustment including waist circumference, non-HDL cholesterol remained associated with incident diabetes [odds ratio (OR) 1.42 (95% confidence interval, CI 1.07-1.88)], while LDL cholesterol and HDL cholesterol became non-significant. CONCLUSIONS: Non-HDL cholesterol was associated with incident type 2 diabetes and was superior to LDL cholesterol as a risk predictor in this population. Further studies are required to establish the utility of non-HDL cholesterol in non-Aboriginal populations.
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HDL-Colesterol/sangre , Diabetes Mellitus Tipo 2/prevención & control , Indígenas Norteamericanos/etnología , Adolescente , Adulto , Anciano , Niño , LDL-Colesterol/sangre , Diabetes Mellitus Tipo 2/etnología , Dislipidemias/diagnóstico , Dislipidemias/etnología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Ontario/epidemiología , Medición de Riesgo/métodos , Factores de Riesgo , Adulto JovenRESUMEN
BACKGROUND AND AIMS: We aimed to determine the effects on glycemic responses and potential risk of hypoglycaemia in type 1 diabetic subjects of replacing half the starch in a meal with sugars, and of adding fat to the low-sugar and high-sugar meals. METHODS AND RESULTS: We studied overnight fasted subjects with type 1 diabetes (n = 11) and age-, BMI- and ethnicity-matched controls (n = 11) using a 2 × 2 factorial design. The low-sugar/low-fat meal was 110 g white-bread. In the high-sugar/low-fat meal half the white-bread starch replaced by sugars (jam and orange juice). The high-fat meals consisted of the low-fat meals plus 20 g fat (margarine). The significance of the main effects of sugars and fat and the sugar × fat, group × sugar and group × fat interactions were determined by ANOVA. In control and diabetic subjects, respectively, high-sugar significantly reduced time to peak rise by 13% (P = 0.004) and 32% (P = 0.004; group × sugar: P = 0.01) and increased peak rise by 14% and 10% (ns). Adding fat increased time to peak rise by 17-19% in both groups (P = 0.003), reduced peak rise by 31% in normal (P < 0.001) but increased peak rise in diabetic subjects by 3% (ns) (group × fat: P = 0.022). Blood glucose nadir and occurrence of hypoglycaemia were similar among the 4 meals. CONCLUSIONS: In type 1 diabetes, insulin adjustment to avoid hypoglycemia may be useful for meals in which the proportion of carbohydrate absorbed as glucose is <0.75, however the precise level which increases hypoglycaemic risk requires further research. The results suggest that people with type 1 diabetes should not be advised to add fat to meals to reduce glycemic responses.
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Diabetes Mellitus Tipo 1/sangre , Grasas de la Dieta/administración & dosificación , Sacarosa en la Dieta/administración & dosificación , Hipoglucemia/sangre , Periodo Posprandial , Adolescente , Adulto , Glucemia/análisis , Estudios de Casos y Controles , Diabetes Mellitus Tipo 1/metabolismo , Ayuno , Femenino , Humanos , Hipoglucemia/prevención & control , Modelos Lineales , Masculino , Persona de Mediana Edad , Factores de Riesgo , Almidón/administración & dosificación , Circunferencia de la Cintura , Adulto JovenRESUMEN
BACKGROUND/OBJECTIVE: To compare postprandial responses elicited by sucromalt, a nutritive sweetener produced by treating a blend of sucrose and corn syrup with an enzyme from Leuconostoc mesenteroides, with those after 42% of high-fructose corn syrup (HFCS), and to see if the reduced responses after sucromalt could be accounted for by carbohydrate malabsorption. SUBJECT AND METHODS: Three experiments were performed in separate groups of normal subjects studied after overnight fasts using double-blind, randomized, cross-over designs. HFCS was used as the control because it contained a similar amount of fructose as sucromalt. Experiment 1 (n = 10): plasma glucose and insulin were measured after 50 g sucromalt and 50 g HFCS. Experiment 2 (n = 10): metabolic profiles were measured after 80 g HFCS, 80 g sucromalt or 56 g fructose/glucose blend plus 24 g inulin. Experiment 3 (n = 20): the glycaemic indices of sucromalt and HFCS were determined. RESULTS: Mean glucose and insulin responses after sucromalt were 66 and 62%, respectively, of those after HFCS (P < 0.05). The inulin treatment, used to mimic the effects of carbohydrate malabsorption, elicited higher breath hydrogen (H2), lower glucose and insulin responses, and a significantly earlier rise in serum free fatty acids (FFA) than those of HFCS (all P < 0.05). Sucromalt elicited no rise in breath H2, and delayed falls in glucose and insulin, and a delayed rebound of FFA compared to HFCS (all P < 0.05). CONCLUSIONS: The reduced glucose and insulin responses elicited by sucromalt are not explained by malabsorption and are more likely related to differences in either rate of digestion and absorption or postabsorptive handling by body.
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Glucemia/metabolismo , Carbohidratos de la Dieta/farmacocinética , Disacáridos/farmacocinética , Fructosa/farmacocinética , Insulina/sangre , Absorción Intestinal/efectos de los fármacos , Adulto , Área Bajo la Curva , Pruebas Respiratorias , Estudios Cruzados , Método Doble Ciego , Femenino , Humanos , Absorción Intestinal/fisiología , Cinética , Masculino , Periodo Posprandial , Sacarosa/farmacocinética , Zea maysRESUMEN
BACKGROUND: Colonic fermentation of dietary fibre to short-chain fatty acids (SCFA) influences appetite hormone secretion in animals, but SCFA production is excessive in obese animals. This suggests there may be resistance to the effect of SCFA on appetite hormones in obesity. OBJECTIVES: To determine the effects of inulin (IN) and resistant starch (RS) on postprandial SCFA, and gut hormone (glucagon-like peptide (GLP-1), peptide-tyrosine-tyrosine (PYY) and ghrelin) responses in healthy overweight/obese (OWO) vs lean (LN) humans. SUBJECTS/METHODS: Overnight-fasted participants (13 OWO and 12 LN) consumed 300 ml water containing 75 g glucose (GLU) as control or 75 g GLU plus 24 g IN, or 28.2 g RS using a randomised, single-blind, cross-over design. Blood for appetite hormones and SCFA was collected at intervals over 6 h. A standard lunch was served 4 h after the test drink. RESULTS: Relative to GLU, IN, but not RS, significantly increased SCFA areas under the curve (AUC) from 4-6 h (AUC4-6). Neither IN nor RS affected GLP-1 or PYY-AUC4-6. Although neither IN nor RS reduced ghrelin-AUC4-6 compared with GLU, ghrelin at 6 h after IN was significantly lower than that after GLU (P<0.05). After IN, relative to GLU, the changes in SCFA-AUC4-6 were negatively related to the changes in ghrelin-AUC4-6 (P=0.017). SCFA and hormone responses did not differ significantly between LN and OWO. CONCLUSIONS: Acute increases in colonic SCFA do not affect GLP-1 or PYY responses in LN or OWO subjects, but may reduce ghrelin. The results do not support the hypothesis that SCFA acutely stimulate PYY and GLP-1 secretion; however, a longer adaptation to increased colonic fermentation or a larger sample size may yield different results.
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Depresores del Apetito/administración & dosificación , Ácidos Grasos Volátiles/sangre , Ghrelina/antagonistas & inhibidores , Inulina/administración & dosificación , Sobrepeso/sangre , Prebióticos/administración & dosificación , Delgadez/sangre , Adulto , Depresores del Apetito/uso terapéutico , Índice de Masa Corporal , Estudios Cruzados , Ácidos Grasos Volátiles/metabolismo , Femenino , Fermentación , Microbioma Gastrointestinal , Ghrelina/sangre , Ghrelina/metabolismo , Péptido 1 Similar al Glucagón/sangre , Péptido 1 Similar al Glucagón/metabolismo , Humanos , Inulina/uso terapéutico , Almuerzo , Masculino , Persona de Mediana Edad , Sobrepeso/dietoterapia , Sobrepeso/metabolismo , Sobrepeso/microbiología , Péptido YY/sangre , Péptido YY/metabolismo , Periodo Posprandial , Método Simple Ciego , Almidón/administración & dosificación , Delgadez/metabolismo , Delgadez/microbiologíaRESUMEN
BACKGROUND/OBJECTIVES: Colonic fermentation of dietary fiber to short-chain fatty acids (SCFA) may protect against obesity and diabetes, but excess production of colonic SCFA has been implicated in the promotion of obesity. We aimed to compare the effects of two fermentable fibers on postprandial SCFA and second-meal glycemic response in healthy overweight or obese (OWO) vs lean (LN) participants. SUBJECTS/METHODS: Using a randomized crossover design, 13 OWO and 12 LN overnight fasted participants were studied for 6 h on three separate days after consuming 300 ml water containing 75 g glucose (GLU) as control or with 24 g inulin (IN) or 28 g resistant starch (RS). A standard lunch was served 4 h after the test drink. RESULTS: Within the entire group, compared with control, IN significantly increased serum SCFA (P<0.001) but had no effect on free-fatty acids (FFA) or second-meal glucose and insulin responses. In contrast, RS had no significant effect on SCFA but reduced FFA rebound (P<0.001) and second-meal glucose (P=0.002) and insulin responses (P=0.024). OWO had similar postprandial serum SCFA and glucose concentrations but significantly greater insulin and FFA than LN. However, the effects of IN and RS on SCFA, glucose, insulin and FFA responses were similar in LN and OWO. CONCLUSIONS: RS has favorable second-meal effects, likely related to changes in FFA rather than SCFA concentrations. However, a longer study may be needed to demonstrate an effect of RS on SCFA. We found no evidence that acute increases in SCFA after IN reduce glycemic responses in humans, and we were unable to detect a significant difference in SCFA responses between OWO vs LN subjects.
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Ácidos Grasos Volátiles/sangre , Inulina/farmacología , Sobrepeso/tratamiento farmacológico , Periodo Posprandial/efectos de los fármacos , Almidón/farmacología , Adolescente , Adulto , Anciano , Glucemia/efectos de los fármacos , Estudios Cruzados , Femenino , Humanos , Peso Corporal Ideal/fisiología , Insulina/sangre , Masculino , Comidas/efectos de los fármacos , Persona de Mediana Edad , Sobrepeso/sangre , Almidón/análogos & derivados , Adulto JovenRESUMEN
Modifying the rate of absorption has been proposed as a therapeutic principle of specific relevance to diabetes. To demonstrate clearly the metabolic benefits that might result from reducing the rate of nutrient delivery, nine healthy volunteers took 50 g glucose in 700 ml water on two occasions: over 5-10 min (bolus) and at a constant rate over 3.5 h (sipping). Despite similar 4-h blood glucose areas, large reductions were seen in serum insulin (54 +/- 10%, P less than 0.001) and C-peptide (47 +/- 12%, P less than 0.01) areas after sipping, together with lower gastric inhibitory polypeptide and enteroglucagon levels and urinary catecholamine output. There was also prolonged suppression of plasma glucagon, growth hormone, and free-fatty acid (FFA) levels after sipping, whereas these levels rose 3-4 h after the glucose bolus. An intravenous glucose tolerance test at 4 h demonstrated a 48 +/- 10% (P less than 0.01) more rapid decline in blood glucose (Kg) after sipping than after the bolus. Furthermore, FFA and total branched-chain amino acid levels as additional markers of insulin action were lower over this period despite similar absolute levels of insulin and C-peptide. These findings indicate that prolonging the rate of glucose absorption enhances insulin economy and glucose disposal.
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Prueba de Tolerancia a la Glucosa/métodos , Glucosa/administración & dosificación , Administración Oral , Aminoácidos/sangre , Glucemia/metabolismo , Péptido C/sangre , Esquema de Medicación , Epinefrina/orina , Ácidos Grasos no Esterificados/sangre , Polipéptido Inhibidor Gástrico/sangre , Humanos , Insulina/sangre , Norepinefrina/orina , Valores de ReferenciaRESUMEN
The glycaemic index (GI) concept was originally introduced to classify different sources of carbohydrate (CHO)-rich foods, usually having an energy content of >80 % from CHO, to their effect on post-meal glycaemia. It was assumed to apply to foods that primarily deliver available CHO, causing hyperglycaemia. Low-GI foods were classified as being digested and absorbed slowly and high-GI foods as being rapidly digested and absorbed, resulting in different glycaemic responses. Low-GI foods were found to induce benefits on certain risk factors for CVD and diabetes. Accordingly it has been proposed that GI classification of foods and drinks could be useful to help consumers make 'healthy food choices' within specific food groups. Classification of foods according to their impact on blood glucose responses requires a standardised way of measuring such responses. The present review discusses the most relevant methodological considerations and highlights specific recommendations regarding number of subjects, sex, subject status, inclusion and exclusion criteria, pre-test conditions, CHO test dose, blood sampling procedures, sampling times, test randomisation and calculation of glycaemic response area under the curve. All together, these technical recommendations will help to implement or reinforce measurement of GI in laboratories and help to ensure quality of results. Since there is current international interest in alternative ways of expressing glycaemic responses to foods, some of these methods are discussed.
RESUMEN
The glycemic index (GI) is a classification of foods based on their blood glucose-raising potential. The American Diabetes Association (ADA) has questioned the clinical utility of the GI and recommends that priority should be given to the amount rather than the source of carbohydrate. Some have interpreted this to mean that all carbohydrates have a nearly equal impact on blood sugar, and some feel that the GI is now a dead issue. Nevertheless, the reasons for questioning the clinical utility of the GI are unfounded because of the following: 1) they are based on studies of single test meals, which provide insufficient evidence on which to base dietary recommendations; 2) they are based on a faulty interpretation of the studies actually cited as evidence; 3) they take no account of better designed studies showing that the GI does apply in mixed meals; and 4) they take no account of studies showing that a low-GI diet improves overall blood glucose control in persons with diabetes. The GI is a valid and potentially useful concept, but is also deceptively complex. There are a number of unresolved problems and unanswered questions, and the appropriate place for the GI in patient education is not known. However, progress cannot be made without balance and objectivity.
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Glucemia/análisis , Diabetes Mellitus/sangre , Alimentos/clasificación , HumanosRESUMEN
Different starchy foods produce different glycemic responses when fed individually, and there is some evidence that this also applies in the context of the mixed meal. A major reason appears to relate to the rate at which the foods are digested and the factors influencing this. A similar ranking in terms of glycemic response to specific foods is seen independent of the carbohydrate tolerance status of the groups tested. Potentially clinically useful starchy foods producing relatively flat glycemic responses have been identified. Many of these are considered ethnic or traditional and include legumes; pasta; grains such as barley, parboiled rice, and bulgur (cracked wheat); and whole-grain breads such as pumpernickel. Specific incorporation of these foods into diets has been associated with reductions in low-density lipoprotein cholesterol and triglyceride levels in hyperlipidemia and with improved blood glucose control in insulin-dependent diabetic patients. To facilitate identification of such foods, it has been suggested that the glycemic response should be indexed to a standard (e.g., white bread) to allow comparisons to be made between the glycemic index of foods tested in different groups of subjects. The scope of application of this principle is subject to further investigation. It may be used to expand the range of possibly useful starchy foods for trial in the diets of diabetic patients.
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Glucemia/metabolismo , Diabetes Mellitus Tipo 1/sangre , Diabetes Mellitus Tipo 2/sangre , Carbohidratos de la Dieta , Almidón , Pan , Grano Comestible , Humanos , Valores de ReferenciaRESUMEN
OBJECTIVE: To determine the effect of varying the amount of carbohydrate and glycemic index (GI) of breakfast test meals on plasma free fatty acid (FFA) responses of nondiabetic subjects and to see whether the glycemic response at lunch was related to the plasma FFA response to breakfast. RESEARCH DESIGN AND METHODS: We studied eight subjects over a 6-h period on four separate occasions using a randomized Latin-square design. They received isocaloric breakfast test meals that were either high (84 g) or low (41 g) in carbohydrate and had either a high (approximately 100) or a low (approximately 70) GI, followed by a standard lunch 4 h later. RESULTS: The initial fall in plasma FFAs after breakfast was similar for all four test meals, but the extent of rebound differed significantly. The mean plasma FFA concentration just before the start of lunch (4 h) was highest after the low-GI, low-carbohydrate breakfast (418 +/- 42 mumol/l), followed by high-GI, low-carbohydrate (277 +/- 48 mumol/l), high-GI, high carbohydrate (227 +/- 32 mumol/l), and low-GI, high-carbohydrate (149 +/- 23 mumol/l) (P < 0.01). The concentration of plasma FFAs at 4 h was directly related to the total area under the glycemic response curve to lunch (r = 0.691, n = 32, P < 0.0001). CONCLUSIONS: In nondiabetic subjects, the type and amount of carbohydrate eaten at breakfast influences the plasma glucose, insulin, and FFA responses to breakfast and also affects the glucose, insulin, and FFA responses to a subsequent standard lunch. The glycemic responses after lunch were closely related to the plasma FFA concentration 4 h after breakfast, which we speculate is due to the inhibitory effect of FFAs on insulin action.
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Glucemia/metabolismo , Carbohidratos de la Dieta , Ácidos Grasos no Esterificados/sangre , Adulto , Índice de Masa Corporal , Peso Corporal , Ritmo Circadiano , Ingestión de Energía , Femenino , Humanos , Insulina/sangre , Masculino , Distribución Aleatoria , Análisis de Regresión , Triglicéridos/sangreRESUMEN
The blood glucose response to feeding 50-g carbohydrate portions of white and wholemeal bread and white spaghetti was studied in a group of nine diabetic subjects. Blood glucose rises after white and wholemeal bread were identical, but the response after spaghetti was markedly reduced. These results emphasize that food form rather than fiber may be important in determining the glycemic response and that pasta may be a useful source of carbohydrate in the diabetic diet.
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Glucemia/análisis , Diabetes Mellitus/dietoterapia , Carbohidratos de la Dieta/administración & dosificación , Fibras de la Dieta/administración & dosificación , Triticum , Anciano , Análisis de Varianza , Pan , Ingestión de Alimentos , Femenino , Harina , Humanos , Masculino , Persona de Mediana EdadRESUMEN
Unexpected plasma glucose responses to different mixed meals fed to normal and diabetic volunteers have recently been reported. We have therefore examined in normal volunteers the effect of mixing carbohydrate foods of different glycemic indices (GIs) without the addition of fat and protein. The observed GI of the mixed meal was within 2% of the expected value. In studies in the literature where fat and protein were added to mixed meals, the observed blood glucose responses also related significantly to the meal GIs calculated from the individual foods. Addition of fat and protein in the quantities used did not obscure this relationship. Studies to determine sources of error in comparing glycemic responses showed that type II diabetic patients displayed the least within-individual variation, and type I diabetic patients the most. Expression of results as the GI rather than as absolute glycemic response areas reduced by 50% the between-subject variation. The mean GI values of rice tested in type I and type II patients were similar (82 +/- 22 compared with 74 +/- 19) and the reproducibility 22 mo later in the same group of subjects was excellent (81 +/- 15 compared with 83 +/- 15). However, the lack of precise GI values for all foods fed in the test meals indicates a need for GI values to be derived for a wider range of individual foodstuffs. The GI approach to classifying foods according to physiologic effect may play a useful role in planning meals and diets in which specific blood glucose profiles are required.
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Glucemia/metabolismo , Pan , Diabetes Mellitus/dietoterapia , Dieta para Diabéticos , Adulto , Anciano , Diabetes Mellitus/sangre , Diabetes Mellitus Tipo 1/sangre , Diabetes Mellitus Tipo 1/dietoterapia , Diabetes Mellitus Tipo 2/sangre , Diabetes Mellitus Tipo 2/dietoterapia , Carbohidratos de la Dieta/farmacología , Grasas de la Dieta/farmacología , Proteínas en la Dieta/farmacología , Femenino , Humanos , Masculino , Persona de Mediana EdadRESUMEN
We studied 12 subjects with diabetes to determine how well the glycemic index (GI) predicted the ranking of glycemic responses of different foods in individuals. All subjects ate three mixed meals (bread, rice, or spaghetti with GIs of 100, 79, and 61, respectively) four times in a randomized complete block design. The mean glycemic response areas of the different meals ranked according to the predicted GI in every individual. The observed mean +/- SD GI values of the meals were significantly different from each other (bread 100 +/- 7, rice 75 +/- 9, spaghetti 54 +/- 9), with no significant difference in response between subjects. It is concluded that individuals share common mean GI values for different foods. Within confidence limits determined by the variability of glycemic responses, the number of repeated tests conducted, and the expected GI difference, the GI can be used to predict the ranking of the mean glycemic responses of mixed meals taken by individuals.
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Glucemia/metabolismo , Diabetes Mellitus/sangre , Carbohidratos de la Dieta , Adulto , Anciano , Pan , Péptido C/sangre , Diabetes Mellitus Tipo 1/sangre , Diabetes Mellitus Tipo 2/sangre , Ingestión de Energía , Ayuno , Femenino , Harina , Humanos , Masculino , Persona de Mediana Edad , Oryza , Distribución AleatoriaRESUMEN
OBJECTIVE: To determine whether low-glycemic index (GI) diets have clinical utility in overweight patients with non-insulin-dependent diabetes mellitus (NIDDM). RESEARCH DESIGN AND METHODS: Six patients with NIDDM were studied on both high- and low-GI diets of 6-wk duration with metabolic diets with a randomized crossover design. Both diets were of similar composition (57% carbohydrate, 23% fat, and 34 g/day dietary fiber), but the low-GI diet had a GI of 58 compared with 86 for the high-GI diet. RESULTS: Small and similar amounts of weight were lost on both diets: 2.5 kg on high-GI diet and 1.8 kg on low-GI diet. On the low-GI diet, the mean level of serum fructosamine, as an index of overall blood glucose control, was lower than on the high-GI diet by 8% (P less than 0.05), and total serum cholesterol was lower by 7% (P less than 0.01). CONCLUSIONS: In overweight patients with NIDDM, reducing diet GI improves overall blood glucose and lipid control.
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Glucemia/metabolismo , Diabetes Mellitus Tipo 2/dietoterapia , Diabetes Mellitus/dietoterapia , Dieta para Diabéticos , Dieta Reductora , Carbohidratos de la Dieta , Obesidad , Colesterol/sangre , HDL-Colesterol/sangre , LDL-Colesterol/sangre , Diabetes Mellitus/fisiopatología , Diabetes Mellitus Tipo 2/fisiopatología , Femenino , Fructosamina , Hexosaminas/sangre , Humanos , Masculino , Persona de Mediana Edad , Triglicéridos/sangre , Pérdida de PesoRESUMEN
To see whether food form, the degree of cooking, or protein enrichment affected the glycemic response to pasta, we gave test-meal breakfasts to 13 diabetic patients. Macaroni had a significantly greater glycemic index (GI) (68 +/- 8) than spaghetti (45 +/- 6, P less than .01); the GI of star pastina was intermediate (54 +/- 6). The GI of spaghetti was not significantly affected by cooking for 5 or 15 min (45 +/- 6 and 46 +/- 5, respectively), or by protein enrichment (38 +/- 4). The GI of spaghetti was similar in 11 non-insulin-dependent and 6 insulin-dependent diabetic patients (49 +/- 7 compared with 57 +/- 8). We conclude that different types of pasta may produce different glycemic responses but that these are not necessarily related to differences in cooking or surface area.
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Glucemia/metabolismo , Carbohidratos de la Dieta/metabolismo , Proteínas en la Dieta , Culinaria , Alimentos Fortificados , Calor , HumanosRESUMEN
OBJECTIVE: To determine the true prevalence of impaired glucose tolerance (IGT), NIDDM, and associated risk factors by age and sex in an isolated native community. RESEARCH DESIGN AND METHODS: A community-wide prevalence survey using a 75-g oral glucose tolerance test (OGTT) was undertaken in the remote native reserve of Sandy Lake, Ontario, Canada. Measurements for obesity included waist-to-hip circumference, BMI, and percentage body fat. RESULTS: A total of 728 individuals were enrolled, representing a community participation rate of 72%. The overall crude prevalence of NIDDM was 17.2% (18.1% females and 16.0% males) and increased to 26.1% overall (28.0% females and 24.2% males) when age-standardized. The prevalence of IGT was higher in females compared with males (age-standardized prevalence of 19.8 vs. 7.1%, respectively). Females had a higher prevalence of obesity, IGT, and NIDDM occurring at younger ages. Measures of obesity and fasting insulin levels were significantly associated with NIDDM in the 18-49 age-group. CONCLUSIONS: The prevalence rates of NIDDM in this study population are the highest reported to date in a Canadian native population and among the highest reported in the world. Females appear to be at much higher risk of developing obesity, IGT, and NIDDM and at a younger age. Due to the high prevalence rates of IGT and NIDDM in this young population, there is urgent need to develop culturally appropriate community-based public health intervention programs before the long-term complications of diabetes have a devastating effect on the residents.
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Diabetes Mellitus Tipo 2/epidemiología , Intolerancia a la Glucosa/epidemiología , Adolescente , Adulto , Distribución por Edad , Análisis de Varianza , Composición Corporal , Constitución Corporal , Índice de Masa Corporal , Niño , Estudios Transversales , Femenino , Prueba de Tolerancia a la Glucosa , Humanos , Masculino , Persona de Mediana Edad , Ontario/epidemiología , Prevalencia , Factores de Riesgo , Distribución por SexoRESUMEN
OBJECTIVE: To compare within-subject variability of plasma glucose measured 2 h after a glucose tolerance test (GTT) with that of plasma glucose measured 2 h after administration of a standardized test meal (diabetes screening product [DSP], Ceapro, Edmonton, Alberta, Canada) and to determine the relationship between the two sets of plasma glucose measurements. RESEARCH DESIGN AND METHODS: Plasma glucose and insulin responses of 36 overnight-fasted subjects (10 lean normal, 9 obese normal, 9 with impaired glucose tolerance [IGT], and 8 with mild diabetes) were studied on eight different mornings after they consumed 75 g oral glucose or 50 g carbohydrate from the DSP. Each test meal was repeated four times by each subject. Within-subject coefficients of variation (CVs) (CV = 100 x SD/mean) of plasma glucose concentrations 2 h after administration of the GTT and DSP were compared by repeated measures ANOVA and linear regression analysis. RESULTS: Mean plasma glucose 2 h after administration of the DSP (D) was linearly related to that 2 h after the GTT (G): G = 1.5 x D - 1.6 (r = 0.97, P < 0.0001). The CV of 2-h plasma glucose was significantly lower after administration of the DSP, 10.5 +/- 1.0%, than after the GTT, 12.7 +/- 1.18% (P = 0.025). The effect of test meal on CV differed in different groups of subjects (P = 0.018), with the largest difference found in IGT subjects, in whom the CV after DSP administration was 47% less than after the GTT (P = 0.0005). The DSP was significantly more palatable and produced fewer adverse symptoms than the GTT. CONCLUSIONS: Plasma glucose concentrations measured 2 h after DSP administration are closely related to those measured 2 h after the GTT but are more consistent than the 2-h post-GTT concentrations within the critical IGT range. This finding suggests that measurement of plasma glucose 2 h after administration of the DSP may allow more precise discrimination among normal glucose levels, IGT, and diabetes than measurement of plasma glucose 2 h after the GTT.