Increased insulin receptor binding to monocytes from insulin-dependent diabetic patients after a low-fat, high-starch, high-fiber diet

A High-Fiber Diet Decreases Postabsorptive Protein Turnover but Does Not Alter Insulin Sensitivity in Men with Type 1 Diabetes Mellitus

BACKGROUND

High-fiber diets (HFDs) are recommended in the diet of persons with diabetes, yet such diets can impair macronutrient digestion and/or absorption, modify insulin sensitivity, and reset metabolism.

OBJECTIVES

We studied the effects of a HFD on the kinetics of whole-body protein, a macronutrient that could be affected by dietary fiber, in type 1 diabetes mellitus (T1DM), under both basal-low insulinemic and hyperinsulinemic conditions.

METHODS

Eight men with T1DM (body mass index range: 21.8-27.8 kg/m2) were studied twice - before and after the addition of guar gum (∼15 g/d) to their usual diet for ∼4 mo. Whole-body protein degradation (i.e., the rate of appearance [Ra] of endogenous leucine), leucine disposal to protein synthesis (PS), deamination, and reamination, were determined before and after the HFD, both in the postabsorptive state and following a euglycemic, hyperinsulinemic, hyperaminoacidemic clamp, using isotope dilution methods.

RESULTS

After the HFD, mean values (± SEs) for postabsorptive leucine Ra decreased by ∼20%: from 2.52 (0.15) to 2.03 (0.16) μmol x kg-1 x min-1, P < 0.049, after vs. before the HFD respectively. PS also decreased, by ∼25%: from 2.03 (0.15) to 1.57 (0.15), P < 0.045. Leucine concentration (P = 0.1) and reamination (P = 0.095) decreased moderately, whereas deamination was unchanged. Following the clamp, plasma amino acid concentrations (P < 0.001), leucine deamination (+ ∼50%, P < 0.00002), reamination (+ ∼30%, P < 0.0007), and PS (+ ∼35%, P < 0.00001) were all increased compared with postabsorptive state values, whereas endogenous leucine Ra was suppressed (by 15%, P < 0.00001, and by 25%, P < 0.001, with the primary or the reciprocal pool models, respectively). No significant differences in these insulin effects before compared with after the HFD were observed. Metabolic control (glycated hemoglobin), daily insulin requirement, and insulin-mediated glucose disposal were unchanged after the HFD.

CONCLUSIONS

A HFD downregulates postabsorptive protein turnover in men with T1DM, by decreasing both protein degradation and synthesis, possibly due to a subtle decrease and/or delay in amino acid absorption. It does not significantly affect the insulin (and amino acid sensitivity) to protein turnover, glucose disposal, and metabolic control.

Dietary fiber intakes and insulin requirements in pregnant women with type 1 diabetes

OBJECTIVE

To determine whether higher dietary fiber intake (water soluble and insoluble) is associated with lower insulin requirements and better glycemic control in pregnant women with type 1 diabetes consuming a self-selected diet.

DESIGN

A longitudinal, observational study.

SUBJECTS

Pregnant women (n=141) with type 1 diabetes participating in an interdisciplinary program examining the effects of glycemic control on pregnancy outcome (Diabetes and Pregnancy Program, University of Cincinnati Medical Center).

MEASUREMENTS

We determined total, water soluble and insoluble fiber intakes from 3-day food records kept each trimester during pregnancy. Outcome measures were insulin dose, pre-meal blood glucose, and glycated hemoglobin concentrations.

STATISTICAL ANALYSES

Correlation coefficients, multiple regression, mixed-model analysis of variance.

RESULTS

Mean intakes (g/day) of total, water soluble fiber, and insoluble fiber were 14.0 (range, 1.8-33.1), 4.8 (range, 0.6-10.5) and 9.0 (range, 1.1-24.0), respectively. In the second and third trimesters of pregnancy, insulin requirements were inversely associated with total, water soluble, and insoluble fiber intakes; the correlation coefficients ranged from -0.22 to -0.17 (P=.02 to .08). Insulin requirements associated with a higher fiber intake (20.5 g/day) were 16% to 18% lower than for a lower fiber intake (8.1 g/day). These relations remained after adjustment for body weight, disease severity and duration, insulin type, and study year in the second (P=.03 to .10) but not in the third trimester. Pre-meal blood glucose and glycated hemoglobin concentrations were not associated with fiber intake.

CONCLUSIONS

Among pregnant women with type 1 diabetes, higher fiber intake is associated with lower daily insulin requirements. Dietary fiber intake should be considered when counseling patients about the management of blood glucose concentrations.

Improvement of insulin sensitivity and dyslipidemia with a new alpha-glucosidase inhibitor, voglibose, in nondiabetic hyperinsulinemic subjects

This study was undertaken to investigate the effect of voglibose, a new alpha-glucosidase inhibitor, on glucose and lipid metabolism in nondiabetic hyperinsulinemic subjects. Sixteen nondiabetic subjects with hyperinsulinemia participated in the study. They were divided into two groups of eight subjects with normal (NGT) and impaired (IGT) glucose tolerance. A meal tolerance test and a 75-g oral glucose tolerance test (OGTT) were performed at the beginning (baseline phase) and end (treatment phase) of the 12-week treatment. Serum lipid levels were measured every 4 weeks throughout the treatment phase and follow-up phase (8 weeks). All patients received 1 0.2-mg tablet of voglibose before each test meal (3 tablets per day). We also measured insulin sensitivity using a steady-state plasma glucose (SSPG) method in eight normotensive hyperinsulinemic subjects and in eight age- and body mass index (BMI)-matched control subjects before and after the drug treatment. Voglibose significantly decreased the responses of plasma glucose and insulin on the meal tolerance test. The area under the curve for 2-hour insulin during the 75-g OGTT decreased after treatment, whereas that for 2-hour glucose did not change before and after treatment. SSPG was reduced after treatment, indicating improvement of insulin sensitivity. Moreover, treatment with voglibose resulted in a significant decline of triglyceride level and an elevation of high-density lipoprotein (HDL) cholesterol and apolipoprotein A-1. These values returned to near-baseline levels after the drug was discontinued. Consequently, we conclude that this agent not only has a direct hypoglycemic effect through decreased absorption of carbohydrate, but also a hypoinsulinemic and hypolipidemic effect via improved insulin sensitivity.

Usual dietary intake and hemoglobin A1 level in patients with insulin-dependent diabetes

OBJECTIVE

To explore epidemiologic evidence for the relationship between dietary intake and glycemic control.

DESIGN/SUBJECTS

We examined usual dietary intake, assessed by a food frequency questionnaire, from a random sample (n = 136) of patients who had had insulin-dependent diabetes mellitus for 15 to 21 years.

RESULTS

In men, absolute intakes of energy, carbohydrate, protein, fat, and dietary fiber were positively correlated with hemoglobin A1 (HbA1) (P < .05); Spearman correlation coefficients (rs) were .28, .22, .28, .34, and .25, respectively. In women, the correlations were weaker and not significant; rs values were .18, .13, .17, .19, and .16, respectively. When these nutrients were expressed as a percentage of energy or as an amount per 1,000 kcal, only percentage of energy from fat showed a significant association with HbA1--but only in men (rs = .23 for men and .02 for women). Adjustment for body weight, insulin dose, and physical activity using multiple regression analysis did not change the relationship between HbA1 and intakes of energy and fat. Sucrose and alcohol intakes did not show any association with HbA1.

CONCLUSIONS

Among men with insulin-dependent diabetes mellitus, the major dietary correlates of poor glycemic control were high intake of energy and percentage of energy from fat. Further investigation is needed to confirm this relationship of energy, fat, and glycemic control.

No effects of high-fiber diets on metabolic control and insulin-sensitivity in type 1 diabetic subjects

The metabolic effects of a three-month treatment with a high-fiber diet (15 grams of guar-gum added to a standard diet) were investigated in seven type 1 diabetic subjects, with a moderately poor metabolic control. HbA1c levels, daily insulin requirement, cholesterol, triglyceride, amino acid and intermediate metabolite concentrations were evaluated before and following the high fiber diet, both in the postabsorptive state at euglycemia and during a euglycemic, hyperinsulinemic, hyperaminoacidemic clamp. Insulin-mediated glucose utilization, an index of insulin-sensitivity, was also measured during the clamp. Following the diet, no differences in HbA1c levels (7.6 +/- 0.7%----7.3 +/- 0.6%), daily insulin requirement (50 +/- 5----51 +/- 3 U/d), triglyceride, amino acid and intermediary metabolite concentrations in the basal, euglycemic state, were observed. Only cholesterol concentrations decreased significantly (from 165 +/- 12 to 142 +/- 12 mg/dl, P less than 0.01) after the diet. During the clamp, the concentrations of all measured substrates were comparable before and after high fiber treatment. Insulin-mediated glucose disposal was also unchanged by guar-gum treatment. Patients' body weights were not modified by the diet. In conclusion, our study shows that a high fiber diet, obtained with the addition of 15 grams of guar-gum to a standard diet, is of no benefit to IDDM either as regards the metabolic control or insulin sensitivity. Only cholesterol levels were decreased. Therefore, the costs and benefits of these diets in the treatment of IDDM should be reconsidered.

Serum insulin and other cardiovascular risk indicators in children, adolescents and young adults

We wanted to determine the levels of fasting serum insulin during growth, the tracking of serum insulin, and the correlation of serum insulin with other coronary heart disease risk indicators in children and young adults. In 1986 2433 subjects, aged nine to 24 were studied, and insulin data were available from the same population in 1980 and 1983. Serum insulin levels showed a peak during puberty in both sexes and the decline in insulin continued after the age of 21. Tracking of serum insulin was only moderate, especially in females and young boys. Serum insulin correlated positively with body mass index, concentrations of serum triglycerides, and blood pressure, and inversely with the concentration of high density lipoprotein cholesterol. High triglycerides, high systolic blood pressure, and low level of high density lipoprotein cholesterol clustered among subjects within the highest insulin quartile. Our results suggest that the insulin resistance phenomenon, caused mainly by obesity and leading to unfavourable levels of other coronary heart disease risk indicators, is already developing in children and young adults. This suggests that preventing obesity in early life is important.

Modulation of postprandial glycaemia and insulinaemia by cellulose in mixed nutrient combinations

The present study was designed to examine the effect of cellulose (CL) on postprandial glycaemia and insulinaemia when ingested with glucose (G), casein (CS) and maize oil (CO) in various combinations. The study was conducted on five healthy male volunteers, on each of whom five meal tolerance tests were performed. The meals were isoenergetic and consisted of G; G and CL; G, CS and CL; G, CO and CL; G, CS, CO and CL. The meals were administered after an overnight fast. In addition to a fasting venous blood sample, blood was collected 0.5, 1.0, 1.5 and 2.0 h after ingestion for measurement of serum glucose and insulin levels. The glycaemic response to G + CS + CL and G + CS + CO + CL was significantly lower, while the insulinaemic response to G + CL was significantly higher than that to G. Addition of CL to G did not alter the glycaemic response, but accentuated the insulinaemic response. Further addition of CS in isoenergetic meals attenuated the glycaemic response, which may be because of a reduction in the amount of G in the meals. Like CS, CL also seemed to have an insulinotropic effect. The mechanism of the insulinotropic effect of CL cannot be deduced from the present study, but it is possible that like G, CL also stimulates gastric inhibitory peptide (GIP) secretion from the duodenum, which in turn stimulates insulin secretion.

The medium-term effect of natural or extractive dietary fibres on plasma amino acids and lipids in type 1 diabetics

We evaluated the effect of a diet rich in natural (NF) or extractive fibres (guar gum) on 12 male IDD (insulin-dependent diabetes) out-patients. The treatment lasted for 2 months. During the first month the patients were on an isocaloric diet containing 30 g of fibres and then they were randomly subdivided into two groups. One group followed an isocaloric diet rich in fibres (70 g/day), the second group an isocaloric diet enriched by guar (9 g of guar added to 30 g of natural fibres/day). Reduced serum levels of HbA1c and several amino acids showed that metabolic control significantly improved under each dietary regimen.

Insulin receptors on circulating blood cells from patients with pancreatogenic diabetes: a comparison with type I diabetes and normal subjects

We studied 125I-insulin binding to erythrocytes from 14 patients with diabetes secondary to chronic pancreatitis or pancreatectomy and compared the results with those found in 10 patients with type I diabetes and 25 normal controls. Patients with pancreatogenic diabetes had higher 125I-insulin binding and enhanced tissue sensitivity to exogenous insulin measured with the glucose clamp technique as compared with patients with type I diabetes. Similar binding data were obtained with monocytes from 3 patients with pancreatogenic diabetes. The increase in insulin binding seemed due mainly to an increase in receptor number. The increase in insulin binding to cells from patients with pancreatogenic diabetes in comparison with cells from normal subjects was also seen in young-erythrocyte-rich fractions and in old-erythrocyte-rich fractions obtained from the mixed population of circulating erythrocytes by centrifugation in density gradient of Percoll-Pielografin. These data, in the absence of any sign of major hematological disorders, suggest that the increase in insulin receptors seen in erythrocytes and in monocytes from patients with pancreatogenic diabetes, can mirror a general phenomenon on tissues throughout the body, including major target cells for insulin and correlate with the heightened sensitivity to insulin characteristic of these patients. In conclusion, patients with pancreatogenic diabetes have increased insulin binding as compared to controls and to patients with type I diabetes with chronic hypoinsulinemia of the same degree. Thus, in addition to insulin deficiency, other factor (s), such as glucagon deficiency, are responsible for the clinical and metabolic differences between these two conditions of insulin deficiency.

The treatment of poorly controlled non-insulin-dependent diabetic subjects with granulated guar gum

The treatment of poorly controlled, non-compliant non-insulin-dependent diabetic subjects for one month with guar granules (Guarem) was associated with significant improvements in fasting serum glucose and insulin and urinary glucose excretion. No significant change was observed in either oral glucose tolerance, erythrocyte insulin receptor binding, serum calcium, cholesterol, triglyceride or HbA1. Subjects reported significant side effects including excessive flatus, increased bowel frequency and fullness. The limited advantages of Guarem treatment must be measured against the possibility of these side effects which to a large extent may be avoided by special attention to the means of administration. Prudent supplementation of the diet with Guarem has undoubted potential for diabetic control.

The influence of guar-gum bread on the regulation of diabetes mellitus type II in elderly patients

The effect of a high-fibre bread mixed with guar-gum (75 g/kg flour) on serum glucose, connecting peptide (C-peptide), haemoglobin A1 (HbA1), high-density-lipoprotein-cholesterol (HDL-cholesterol) and triglycerides was examined in fourteen elderly patients with diabetes mellitus type II. The mean daily consumption of guar gum was 8.1 g. Gastrointestinal disorders were not observed. Consumption of guar-gum bread resulted in a significant decrease in C-peptide values on the 1st day and blood glucose values after 3 weeks (both measured 90 min after breakfast). C-peptide values remained low, while an unaccountable 'rebound' phenomenon was seen in the blood glucose values 90 min after breakfast at the end of the study. No significant change was seen in respect to HDL-cholesterol and triglycerides. However, a small significant increase in HbA1 was noted.

A high prevalence of obesity in a diabetic population: results of a survey of food patterns in 252 patients in a 2 year period

Dietary patterns were reviewed and correlated with the patients' clinical details in 252 patients seen at the initial visit to a diabetic clinic of a major metropolitan teaching hospital. Except in the subgroup of male patients with insulin-dependent diabetes, there was an extremely high prevalence of obesity, especially in females (70% greater 120% of standard weight; 28% greater than 150%). Traditional 'low-carbohydrate' diets were commonly found irrespective of ethnic origin, particularly in those individuals who had received previous dietary education. This study highlights the urgent need for public health education programmes in order to try to prevent the development of obesity since therapy remains unsatisfactory once it is established.

Effect of consuming fiber from corn bran, soy hulls, or apple powder on glucose tolerance and plasma lipids in type II diabetes

The effects of consuming corn bran, soy hulls, or apple powder on glucose and lipid metabolism were investigated in two studies of persons with type II diabetes. Fiber sources, completely or partially added to bread, were incorporated into subjects' self-selected diets. Low fiber white bread served as a control. In study A, 10 subjects consumed 26 g fiber source daily; in study B, eight subjects consumed 52 g fiber source. Biochemical tests, including a 2-h postprandial glucose test using a low fiber formula meal, were scheduled after 2 and 4 wk of each dietary treatment. Soy hull consumption slightly improved some measures of glucose tolerance, with results varying between the studies. Consumption of 52 g corn bran decreased very low-density lipoprotein cholesterol, triglycerides, and glycosylated Hb, but subject tolerance was poor with the particle size used. Consumption of 52 g apple powder increased low-density lipoprotein and total cholesterol levels.

Increased insulin binding to adipocytes and monocytes and increased insulin sensitivity of glucose transport and metabolism in adipocytes from non-insulin-dependent diabetics after a low-fat/high-starch/high-fiber diet

Nine non-insulin-dependent diabetics were studied before and after 3 weeks on an isoenergetic high-fiber/high-starch/low-fat diet (alternative diet), and nine non-insulin-dependent diabetics were studied on their usual diet. In the group that ate the alternative diet, the intake of fiber and starch increased 120% and 53%, whereas fat intake decreased 31%. Diabetes control improved as demonstrated by decreased fasting plasma glucose (P less than 0.05) and 24-hour urinary glucose excretion (P less than 0.05). The in vivo insulin action increased (KIVITT increased, P less than 0.05) with no change in fasting serum insulin levels. In fat cells obtained from patients in the alternative-diet group, insulin receptor binding increased (P less than 0.05) after the change of diet. Insulin binding to purified monocytes (more than 95% monocytes) also increased (P less than 0.05), whereas no change was found in insulin binding to erythrocytes. When lipogenesis was studied at a tracer glucose concentration at which glucose transport seems to be rate limiting, insulin sensitivity increased (P less than 0.02). This is the predicted consequence of increased receptor binding. Moreover, when CO2 production and lipogenesis were studied at a higher glucose concentration, where steps beyond transport seem to be rate limiting for glucose metabolism, increased insulin sensitivity was also observed. In contrast, no change was found in maximal insulin responsiveness. Fat and blood cells from the patients who continued on their usual diet showed no changes of the mentioned quantities.(ABSTRACT TRUNCATED AT 250 WORDS)