Separate influence of dietary carbohydrate and fibre on the metabolic control in diabetes.

Riccardi G, Rivellese A, Pacioni D, Genovese S, Mastranzo P, Mancini M

To clarify the separate influences of digestible carbohydrate and of dietary fibre on blood glucose control and serum lipoproteins, 14 diabetic patients (six Type 1 and eight Type 2) were submitted to three weight-maintaining diets for 10 days each: (1) low carbohydrate/low fibre diet with 42% carbohydrate and 20 g fibre; (2) high carbohydrate/low fibre diet (carbohydrate 53%, fibre 16 g); (3) high carbohydrate/ high fibre diet (carbohydrate 53%, fibre 54 g). In comparison with the low carbohydrate/low fibre diet, the 2-h post-prandial blood glucose and the daily blood glucose profile decreased significantly on the high carbohydrate/high fibre diet, without significant changes during the high carbohydrate/low fibre diet. The diet-induced modifications of blood glucose control were similar in both types of diabetic patients (two-way analysis of variance: F = 5.86, p less than 0.02 for dietary treatment and F = 2.09, NS for type of diabetes). Total and low-density lipoprotein cholesterol were also decreased after the high carbohydrate/high fibre diet in comparison with the low carbohydrate/low fibre diet (p less than 0.001 for both), while they were not significantly modified after the high carbohydrate/low fibre diet. Again the modifications of low density lipoprotein cholesterol induced by diet were similar in both types of diabetic patients (F = 10.02, p less than 0.005 for dietary treatment and F = 0.14 for type of diabetes, NS). High-density lipoprotein cholesterol was lower after the two test diets than after the low carbohydrate/low fibre diet.

Dietary fiber--an overview.

Anderson JW, Akanji AO

Metabolic Research Group, VA Medical Center, Lexington, KY 40511.

Diabetes diets should aim at ensuring an ideal body weight with normoglycemia and normolipidemia. The consensus recommendations of various diabetes associations suggest that these goals are most likely to be achieved by diets high in complex carbohydrates and fiber and low in fat. A typical diabetes diet containing 55-60% energy as carbohydrate (at least 66% complex), less than 30% energy as fat, 0.8 g.kg-1 desirable body wt.day-1 protein, and approximately 40 g fiber/day, improves glycemic control, reduces levels of serum atherogenic lipids, decreases blood pressure in those with hypertension, and reduces body weight in the obese. This diet also reduces insulin requirements in the insulin-treated patient and can promote discontinuation of insulin therapy in those with non-insulin-dependent diabetes mellitus. This article presents our experience with high-fiber high-carbohydrate diets and reviews knowledge on the likely mechanisms of action of fiber, its long-term effectiveness, and the concerns about its long-term safety. We suggest that reports on the risk of hypertriglyceridemia from on the risk of hypertriglyceridemia from high-carbohydrate diets are inconsistent and invalidated if those diets are also high in fiber content. Similarly, we urge some caution in prescribing high-monounsaturated fat diets as an alternative to high-carbohydrate diets, at least until the long-term implications of the former are clearer. We believe that there is no compelling reason to change the current diabetes diets, which should

The role of viscous soluble fiber in the metabolic control of diabetes. A review with special emphasis on cereals rich in beta-glucan.

Wursch P, Pi-Sunyer FX

Nestle Research Centre, Lausanne, Switzerland.

Recent recommendations for the dietary management of diabetes mellitus state that diet needs to be individualized so that there is improved glucose and lipid control in the patient. In a majority of individuals with diabetes, this is best done with a diet that is low in fat and high in carbohydrate, particularly that of cereal origin. However, symptoms of hyper- and hypoglycemia must be averted. Most cereal products, however, tend to have a high glycemic index Cereals such as Prowashonupana barley or fractions of oat bran are particularly high in the soluble fiber beta-glucan, which when taken with a meal increases the viscosity of the meal bolus once it has reached the small intestine, where the absorption of nutrients occurs. This high viscosity delays absorption. A 50% reduction in glycemic peak can be achieved with a concentration of 10% beta-glucan in a cereal food. A significant lowering of plasma LDL cholesterol concentrations can also be anticipated with the daily consumption of > or = 3 g of beta-glucan. Diabetic individuals can benefit from diets that are high in beta-glucan, which, as a component of oats and barley, can be incorporated into breakfast cereals and other products.

[Effectiveness of increased contents of dietary fiber in early stages of non-insulin-dependent diabetes mellitus].

Krashenitsa GM, Botvineva LA, Mogila AV

Patients with early NIDDM were put on routine diet N 9 (food fiber 25 g/day) and test diet (food fiber 55 g/day). The diet of both groups (group 1 and 2, respectively) was supplemented with oral mineral water Essentuki 17. High-fiber diets proved to be effective for the above patients as they induced positive trends in NIDDM clinical symptoms, body weight, lowering of basal insulin, an increase in insulin immediate pool. There was also a reduction of insulinemia and hyperglycemia later in the course of glucose tolerance test. The above shifts were more pronounced in 2 patients. 

Use of dietary fiber to lower cholesterol.

Nuovo J

Department of Family Practice, University of Washington School of Medicine, Seattle.

Dietary water-soluble fiber may be a key factor in the management of hypercholesterolemia. Food items that are rich in this type of fiber are common and are easy to incorporate into a patient's diet. The lipid-lowering effect is dose-related. Consumption of an adequate amount of water-soluble fiber each day may reduce cholesterol levels by 10 to 20 percent.  

Metabolic effects of high-carbohydrate, high-fiber diets for insulin-dependent diabetic individuals.

Anderson JW, Zeigler JA, Deakins DA, Floore TL, Dillon DW, Wood CL, Oeltgen PR, Whitley RJ

Endocrine-Metabolic Section, VA Medical Center, Lexington, KY 40511.

The metabolic effects of high-carbohydrate (70%), high-fiber (70 g) (HCHF) and low-carbohydrate (39%), low-fiber (10 g) (LCLF) diets were examined for 10 subjects with insulin-dependent diabetes mellitus (IDDM). After a 1-wk control period subjects on a metabolic ward were randomly allocated to HCHF or LCLF diets for 4 wk. After a 6-wk washout period subjects re-entered the metabolic ward for 4 wk on the alternate diet. Artificial-pancreas studies were performed on each diet for measurement of insulin requirements. Compared with the LCLF diet, the HCHF diet reduced basal insulin requirements (P less than 0.025), increased carbohydrate disposed of per unit insulin (P less than 0.0008), and lowered total (P less than 0.0004) and high-density-lipoprotein cholesterol (P less than 0.0013). Glycemic control and other lipid fractions did not differ significantly. These results suggest that in IDDM patients, HCHF diets enhance peripheral glucose disposal, decrease basal insulin requirements, and lower total cholesterol without altering glycemic control or triglycerides.

Concentration effect of soluble dietary fibers on postprandial glucose and insulin in the rat.

Vachon C, Jones JD, Wood PJ, Savoie L

Departement de nutrition humaine et de consommation, Faculte des sciences de l'agriculture et de l'alimentation, Universite Laval, Quebec, Canada.

The effects of different soluble fibers on blood glucose and insulin responses to voluntary meals in the rat were investigated. Rats (165-180 g) were adapted for 2 weeks to a fiber-free control diet or fiber diets made by dilution of the fiber-free diet with the fiber. Fibers and concentrations used were carboxymethylcellulose (1.25, 2.5, and 5%), guar gum, oat beta-glucan (2.5, 5, and 7.5%), and mustard mucilage (5, 10, and 15%) as the soluble fibers, and cellulose (20%) as the insoluble fiber. Meal challenges (0.75 g/100 g body weight offered for consumption within a period of 15 min) were made with the adaptation diet. Soluble fibers reduced food intake and growth with a concentration effect, while cellulose increased food intake. All fibers reduced dry matter and nitrogen digestibilities but had no effect on the protein efficiency ratio. Only carboxymethylcellulose (at 5%) reduced postprandial glycemia at 30 min (p less than 0.05). Cellulose had no effect on plasma insulin which was markedly reduced with a concentration effect by all soluble fibers (except mustard mucilage) in the following decreasing order: carboxymethylcellulose, guar gum, beta-glucan, and mustard mucilage. The effect of fibers seemed closely related to the viscosity of fiber solutions in the presence of the diet ingredients. The present findings demonstrate the positive effect of fibers on postprandial insulinemia but with only a slight effect on glycemia. They indicate that the physicochemical interaction of the fibers with other dietary ingredients is important.  

Dietary fiber in management of diabetes.

Vinik AI, Jenkins DJ

Department of Internal Medicine, University of Michigan, Ann Arbor.

Current evidence suggests that high-fiber diets, especially of the soluble variety, and soluble fiber supplements may offer some improvement in carbohydrate metabolism, lower total cholesterol and low-density lipoprotein (LDL) cholesterol, and have other beneficial effects in patients with non-insulin-dependent diabetes mellitus (NIDDM). Diets enriched with wheat bran and guar gum induce 10-20% reductions in serum cholesterol and LDL in both normo- and hypercholesterolemic subjects and have the ability to blunt the hypertriglyceridemic effects of diets high in carbohydrate and low in fiber. In insulin-dependent diabetes mellitus (IDDM) the situation is less clear, but a decrement of the circadian glucose profile has been shown. Americans, in general, consume too little fiber. With the need to restrict fat and reduce protein, an increase in carbohydrates is mandatory. A practical goal would be to establish the present level of fiber intake (15-30 g/day) and to gradually increase it. An intake of up to 40 g of fiber per day or 25 g/1000 kcal of food intake appears beneficial; in many individuals on weight-reducing diets higher levels may be unacceptable because of gastrointestinal side effects. The level of maximum benefit has not been determined. Fiber supplementation appears beneficial only if given with a diet comprising approximately half of the calories as carbohydrate. Foods should be selected with moderate to high amounts of dietary fiber from a wide variety of choices to include both soluble and insoluble types of fiber. Insufficient data are available on the long-term safety of high-fiber supplements. People at risk for deficiencies, such as postmenopausal women, the elderly, or growing children, may require supplements of calcium and trace minerals. People with upper gastrointestinal dysfunction are at risk of bezoar formation and cautioned against a diet high in fiber of the leafy vegetable type. Careful attention must be paid to insulin dose because hypoglycemia can result if there is a radical change in fiber intake and insulin dose is not reduced appropriately. Care must be exercised in the use of "novel" fibers, including the wood celluloses, because little is known of their safety and efficacy.  

JAMA 1997 Feb 12;277(6):472-7

Dietary fiber, glycemic load, and risk of non-insulin-dependent diabetes mellitus in women.

Salmeron J, Manson JE, Stampfer MJ, Colditz GA, Wing AL, Willett WC

Department of Nutrition, Harvard School of Public Health, Boston, Mass, USA.

OBJECTIVE: To examine prospectively the relationship between glycemic diets, low fiber intake, and risk of non-insulin-dependent diabetes mellitus. DESIGN: 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, P trend=.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, P trend=.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, P trend=.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.

Postprandial glucose, insulin, and lipid responses to four meals containing unpurified dietary fiber in non-insulin-dependent diabetes mellitus (NIDDM), hypertriglyceridemic subjects.

Guevin N, Jacques H, Nadeau A, Galibois I

Groupe de Recherche en Nutrition Humaine, Universite Laval, Quebec, Canada.

OBJECTIVE: To evaluate the effects of two levels of total dietary fiber (10 g vs. 20 g) and two soluble:insoluble fiber ratios (1:4 vs. 2:3) on postprandial glucose and lipid metabolism in hypertriglyceridemic subjects with non-insulin-dependent diabetes mellitus (NIDDM). METHODS: Eight NIDDM, mildly hypertriglyceridemic subjects consumed four test breakfasts, each containing variable proportions of the same cereal and fruit fiber sources. Blood samples were obtained during the 4 hours following the test meals and analyzed for glucose, insulin, triglyceride, total cholesterol and high density lipoprotein cholesterol. RESULTS: The incremental area under the curve for glucose and insulin was lowered after consuming 20 g as compared to 10 g of dietary fiber (p < 0.05), but was not affected by the soluble insoluble fiber ratio. The postprandial lipemia was similar after all test meals. CONCLUSION: The proportion of soluble to insoluble fiber in cereal and fruit does not necessarily predict the effect of fiber on the glycemic response, while the overall quantity of fiber does appear to affect postprandial glucose metabolism in NIDDM.

Dietary fiber decreases fasting blood glucose levels and plasma LDL concentration in noninsulin-dependent diabetes mellitus patients.

Hagander B, Asp NG, Efendic S, Nilsson-Ehle P, Schersten B

Department of Community Health Sciences, University of Lund, Dalby, Sweden.

Realistic high-fiber and regular low-fiber diets were given for 8 wk each to noninsulin-dependent diabetes mellitus (NIDDM) patients whose diabetes was being controlled satisfactorily by diet alone. The purpose of the study was to evaluate the metabolic effects of dietary fiber without changing energy intake or proportions of protein, fat, and carbohydrates. The high-fiber diet induced lower fasting blood glucose levels (p less than 0.01) and decreased the ratio of low-density lipoproteins to high-density lipoproteins (p less than 0.025); no difference was found in HbA1c between the two diet periods. Continuous glucose monitoring also showed a difference in fasting glucose levels that remained after identical low-fiber test meals. The incremental glucose responses did not differ. The fasting and incremental postprandial levels of insulin, C-peptide, glucagon, and somatostatin did not change, whereas the mean triglyceride concentrations were lower after the high-fiber diet. The results suggest a beneficial effect of dietary fiber in the metabolic control of NIDDM.  

High-fiber diets in the treatment of diabetes mellitus.

Miranda PM, Horwitz DL

Eight patients with insulin-requiring diabetes were given, in random order, a diet containing 3 g and one containing 20 g of crude fiber. Each diet was maintained for 10 days and was the same in calories, carbohydrate, fat, and protein. Insulin dose was kept constant. Mean plasma glucose on the low-fiber diet was 169.4 +/- 11.7 mg/dl, significantly higher (P less than 0.001) than the value of 120.8 +/- 10.1 on the high-fiber diet. Hypoglycemic reactions were more common on the high-fiber diet. Weight remained essentially constant on both diets. Mean serum glucagon level on the high-fiber diet was significantly lower (P less than 0.001) than on the low-fiber diet, while serum free insulin levels were unchanged. These data indicate that substantial changes in fiber content of the diabetic diet may lead to marked changes in diabetic control and that increasing dietary fiber may be a useful means of lowering plasma glucose in some diabetic patients.  

Dietary fiber decreases fasting blood glucose levels and plasma LDL concentration in noninsulin-dependent diabetes mellitus patients.

Hagander B, Asp NG, Efendic S, Nilsson-Ehle P, Schersten B

Department of Community Health Sciences, University of Lund, Dalby, Sweden.

Realistic high-fiber and regular low-fiber diets were given for 8 wk each to noninsulin-dependent diabetes mellitus (NIDDM) patients whose diabetes was being controlled satisfactorily by diet alone. The purpose of the study was to evaluate the metabolic effects of dietary fiber without changing energy intake or proportions of protein, fat, and carbohydrates. The high-fiber diet induced lower fasting blood glucose levels (p less than 0.01) and decreased the ratio of low-density lipoproteins to high-density lipoproteins (p less than 0.025); no difference was found in HbA1c between the two diet periods. Continuous glucose monitoring also showed a difference in fasting glucose levels that remained after identical low-fiber test meals. The incremental glucose responses did not differ. The fasting and incremental postprandial levels of insulin, C-peptide, glucagon, and somatostatin did not change, whereas the mean triglyceride concentrations were lower after the high-fiber diet. The results suggest a beneficial effect of dietary fiber in the metabolic control of NIDDM.  

Va Med 1979 Nov;106(11):852-5

High-fiber diet: its role in the treatment of diabetes mellitus reviewed.

Van Ness MM, Wheby MS

Dietary manipulation has long been a mainstay of treatment of adult-onset diabetes. Weight loss and a diet low in refined carbohydrate have often allowed either reduction or discontinuation of oral hypoglycemic agents or insulin. The evidence presented in this review suggests that complex carbohydrates and high-fiber compounds can play a significant role in this dietary manipulation and merit further study. The mechanism by which hyperglycemia is ameliorated may be the increased viscosity of intestinal contents with slower small bowel transit time resulting in slow, but sustained absorption of glucose. 

High-fiber diets in the treatment of diabetes mellitus.

Miranda PM, Horwitz DL

Eight patients with insulin-requiring diabetes were given, in random order, a diet containing 3 g and one containing 20 g of crude fiber. Each diet was maintained for 10 days and was the same in calories, carbohydrate, fat, and protein. Insulin dose was kept constant. Mean plasma glucose on the low-fiber diet was 169.4 +/- 11.7 mg/dl, significantly higher (P less than 0.001) than the value of 120.8 +/- 10.1 on the high-fiber diet. Hypoglycemic reactions were more common on the high-fiber diet. Weight remained essentially constant on both diets. Mean serum glucagon level on the high-fiber diet was significantly lower (P less than 0.001) than on the low-fiber diet, while serum free insulin levels were unchanged. These data indicate that substantial changes in fiber content of the diabetic diet may lead to marked changes in diabetic control and that increasing dietary fiber may be a useful means of lowering plasma glucose in some diabetic patients.  

N Engl J Med 2000 May 11;342(19):1392-8

Beneficial effects of high dietary fiber intake in patients with type 2 diabetes mellitus.

Chandalia M, Garg A, Lutjohann D, von Bergmann K, Grundy SM, Brinkley LJ

Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas 75390, USA. BACKGROUND: The effect of increasing the intake of dietary fiber on glycemic control in patients with type 2 diabetes mellitus. METHODS: In a randomized, crossover study, we assigned 13 patients with type 2 diabetes mellitus to follow two diets, each for six weeks: a diet containing moderate amounts of fiber (total, 24 g; 8 g of soluble fiber and 16 g of insoluble fiber), as recommended by the American Diabetes Association (ADA), and a high-fiber diet (total, 50 g; 25 g of soluble fiber and 25 g of insoluble fiber), containing foods not fortified with fiber (unfortified foods). Both diets, prepared in a research kitchen, had the same macronutrient and energy content. We compared the effects of the two diets on glycemic control and plasma lipid concentrations. RESULTS: Compliance with the diets was excellent. During the sixth week, the high-fiber diet, as compared with the the sixth week of the ADA diet, mean daily preprandial plasma glucose concentrations were 13 mg per deciliter [0.7 mmol per liter] lower (95 percent confidence interval, 1 to 24 mg per deciliter [0.1 to 1.3 mmol per liter]; P=0.04) and mean median difference, daily urinary glucose excretion 1.3 g (0.23; 95 percent confidence interval, 0.03 to 1.83 g; P= 0.008). The high-fiber diet also lowered the area under the curve for 24-hour plasma glucose and insulin concentrations, which were measured every two hours, by 10 percent (P=0.02) and 12 percent (P=0.05), respectively. The high-fiber diet reduced plasma total cholesterol concentrations by 6.7 percent (P=0.02), triglyceride concentrations by 10.2 percent (P=0.02), and very-low-density lipoprotein cholesterol concentrations by 12.5 percent (P=0.01). CONCLUSIONS: A high intake of dietary fiber, particularly of the soluble type, above the level recommended by the ADA, improves glycemic control, decreases hyperinsulinemia, and lowers plasma lipid concentrations in patients with type 2 diabetes.

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