Beneficial effect of a low glycaemic index diet in type 2 diabetes

Low glycaemic index foods produce low blood glucose and insulin responses in normal subjects, and improve blood glucose control in Type 1 and well-controlled Type 2 diabetic patients. We studied the effects of a low glycaemic index diet in 15 Type 2 diabetic patients with a mean fasting blood glucose of 9.5 mmol l-1 using a randomized, crossover design. Patients were given pre-weighed diets (59% energy as carbohydrate, 21% fat, and 24 g 1000-kcal-1 dietary fibre) for two 2-week periods, with a diet glycaemic index of 60 during one period and 87 during the other. On the low glycaemic index diet, the blood glucose response after a representative breakfast was 29% less than on the high glycaemic index diet (874 +/- 108 (+/- SE) vs 204 +/- 112 mmol min l-1; p less than 0.001), the percentage reduction being almost identical to the 28% difference predicted from the meal glycaemic index values. After the 2-week low glycaemic index diet, fasting serum fructosamine and cholesterol levels were significantly less than after the high glycaemic index diet (3.17 +/- 0.12 vs 3.28 +/- 0.16 mmol l-1, p less than 0.05, and 5.5 +/- 0.4 vs 5.9 +/- 0.5 mmol l-1, p less than 0.02, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Maintenance of sulfonylurea responsiveness in NIDDM. Randomized double-blind study of intermittent glyburide therapy

OBJECTIVE

To assess the effectiveness of intermittent administration of sulfonylurea (glyburide) to patients with non-insulin-dependent diabetes mellitus (NIDDM).

RESEARCH DESIGN AND METHODS

A randomized, double-blind, prospective trial compared daily administration with intermittent administration of glyburide to patients who initially responded to the drug. Twenty-eight of 60 patients with NIDDM achieved the predetermined improvement in plasma glucose concentration on glyburide therapy. These 28 responders were enrolled into a 16-wk trial of daily versus intermittent (2 wk on, 2 wk off) glyburide treatment. Laboratory assessment of glycemic control and insulin secretion in fasting and 2-h postprandial states was done every 2 wk.

RESULTS

Patients on continuous glyburide therapy maintained their glycemic control throughout the study. In contrast, patients on the intermittent schedule lost their glycemic control immediately after being placed on placebo. Despite a significant response to each sulfonylurea pulse, these subjects never regained their baseline glycemic levels. Their fructosamine and HbA1c concentrations deteriorated and remained significantly higher than those of the continuously treated subjects.

CONCLUSIONS

Results suggest that administration of glyburide on an intermittent basis after a 2-wk drug-free period to patients initially rendered responsive to sulfonylurea therapy is without clinical merit.

The diabetes annual review as an educational tool: assessment and learning integrated with care, screening, and audit. The North Tyneside Diabetes Team

An integrated diabetes Annual Review is described, suitable for the long-term care of large numbers of diabetic patients. Equal weight is given to dietary and educational assessment as to medical care and screening. Based on well-developed team-work the patient moves through a structured review which culminates in goal setting and planned care for the subsequent year. A structured audit of the review was carried out on a cohort of 123 patients of whom 67 had had two annual reviews. Ten patients failed to attend. Knowledge scores improved by 44% between first and second reviews. In 34% of patients in the first year and in 46% in year two, HbA1c levels were outside a target range set for each treatment group, but only 18% had results outside target in both years. A postal questionnaire was returned by 74/108 (69%) patients. This indicated a high level of patient participation and satisfaction with the review process. The diabetes team set standards, conducted the review, and subsequently changed in-house working practices and documentation, and developed in-service training.

Immunoradiometric assay of insulin, intact proinsulin and 32-33 split proinsulin and radioimmunoassay of insulin in diet-treated type 2 (non-insulin-dependent) diabetic subjects

Plasma insulin, intact proinsulin and 32-33 split proinsulin measured by specific immunoradiometric assays and insulin and C-peptide measured by radioimmunoassay were measured during a constant infusion of glucose test in ten diet-treated subjects with a history of Type 2 (non-insulin-dependent) diabetes (termed diabetic subjects), mean fasting plasma glucose 6.0 +/- 1.0 mmol/l (mean +/- SD), and 12 non-diabetic control subjects. Immunoreactive insulin concentrations measured by radioimmunoassay were 33% higher than insulin and 16% higher than the sum of insulin and its precursors by immunoradiometric assay. The diabetic and non-diabetic subjects had similar fasting concentrations of insulin, intact proinsulin and 32-33 split proinsulin. The ratio of fasting intact proinsulin to total insulin was greater in the diabetic than the non-diabetic group 12.0% (6.8-21.0%, 1 SD range) and 6.3% (4.0-9.8%), respectively, p less than 0.01), though the groups overlapped substantially. After glucose infusion, diabetic and non-diabetic subjects had similar intact proinsulin concentrations (geometric mean 4.9 and 5.2 pmol/l, respectively), but the diabetic group had impaired insulin secretion by immunoradiometric assay (geometric means 55 and 101 pmol/l, p less than 0.05) or by radioimmunoassay C-peptide (geometric means 935 and 1410 pmol/l, p less than 0.05), though not by radioimmunoassay insulin (87 and 144 pmol/l, p = 0.12), respectively. Individual immunoradiometric assay insulin responses to glucose expressed in terms of obesity were subnormal in nine of ten diabetic subjects. Radioimmunoassay insulin and C-peptide gave less complete discrimination (subnormal responses in six of ten and eight of ten, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Impact of associated conditions on glycemic control of NIDDM patients

OBJECTIVE

To assess the impact of associated conditions (obesity, dyslipidemia, and hypertension) on the glycemic control of non-insulin-dependent diabetes mellitus (NIDDM) patients under home-life conditions.

RESEARCH DESIGN AND METHODS

We analyzed the metabolic data of 271 NIDDM patients (89% Mexican American) screened in a population-based survey (the San Antonio Heart Study).

RESULTS

Obesity was present in 77% of the patients, hypertension in 23%, hypertriglyceridemia (serum triglycerides greater than 2.9 mM) in 23%, and hypercholesterolemia (serum total cholesterol greater than 6.5 mM) in 14%. Forty percent of the patients had two or more comorbid conditions. With the use of a multiple linear regression model, which was adjusted for age, sex, ethnicity, distribution of body fat (waist-hip ratio), plasma insulin, and treatment (of both diabetes and hypertension), we found that the presence of higher serum triglyceride concentrations was associated with significantly higher plasma glucose levels both in the fasting state (1.4 mM, P less than 0.001) and 2 h after an oral glucose load (1.2 mM, P = 0.003). The presence of obesity, hypertension, or high serum cholesterol levels was not associated with significant changes in glycemic control. When the entire group was stratified by diabetes treatment (untreated n = 89, diet n = 75, oral agents n = 82, insulin n = 25) and after adjusting for age, sex, ethnicity, and waist-hip ratio, only fasting and 2-h plasma glucose and insulin concentrations were significantly different across treatment groups, with diet and oral agents being associated with higher fasting (P less than 0.001) and postglucose (P less than 0.005) plasma glucose levels and lower plasma insulin concentrations (P less than 0.005) compared with newly diagnosed patients. Neither serum lipids nor blood pressure differed across treatment.

CONCLUSIONS

In NIDDM patients under home-life conditions, higher serum triglycerides are associated with higher fasting and postglucose hyperglycemia regardless of antidiabetic treatment. The presence of obesity, hypertension, or high serum cholesterol levels is not associated with significant changes in glycemic control.

British Diabetic Association's discussion paper on the role of 'diabetic' foods. Nutrition Subcommittee of the British Diabetic Association's Professional Advisory Committee

1. Most diabetic foods provide slightly, but not substantially, less energy than comparable non-diabetic products. 2. Many diabetic foods have a higher fat content than their non-diabetic equivalents. This is contrary to the requirements of the 1984 Food Labelling Regulations. 3. Many diabetic products have a relatively high content of protein. 4. In percentage terms, the greatest difference between diabetic and non-diabetic foods remains that of carbohydrate content, particularly carbohydrate other than fructose or sorbitol. On a per portion basis (for instance, per teaspoon of jam) the difference is relatively small and likely to be of minimal practical significance. 5. Diabetic foods cost between 1.5 and 4 times as much as their non-diabetic equivalents. 6. Some ordinary reduced-sugar/low calorie products are preferable to diabetic products in terms of fat and energy content and cost. 7. The promotion and widespread availability of diabetic foods tend to delude patients into believing that these products are advantageous, or even necessary. Their existence also undermines current dietary teaching by implying that people with diabetes cannot eat normal foods. 8. Diabetic foods offer no significant physiological or psychological benefits to diabetic patients and can even be counterproductive to good diabetic control. There is no longer a need for special diabetic foods in the modern dietary management of diabetes.

alpha-Glucosidase inhibition by miglitol in NIDDM patients

OBJECTIVE

To determine the efficacy of the alpha-glucosidase inhibitor miglitol (BAYm 1099) regarding the starch content of food.

RESEARCH DESIGN AND METHODS

Thirty-six non-insulin-dependent diabetes mellitus (NIDDM) subjects were studied in a double-blind randomized study comparing treatment with a single dosage of 100 mg miglitol or placebo and a single-blind crossover comparison of three test meals in which the carbohydrate contained either 30, 50, or 70% starch, and quantities of fat and protein were kept constant.

RESULTS

Postprandial blood glucose excursions were reduced by approximately 50% with miglitol after all test meals. In contrast, after miglitol treatment, maximum postprandial serum C-peptide and insulin values reached the same levels as after placebo treatment, although the time to reach these maximum levels was delayed. Free fatty acid values decreased after both miglitol and placebo similarly. Twenty-eight untoward events in 15 patients were reported in the miglitol treatment group and 11 events in 7 patients in the placebo treatment group.

CONCLUSIONS

Miglitol reduces postprandial blood glucose excursions independent of the starch content of the meal. Because no effects were found on incremental postprandial maximal levels of serum insulin and C-peptide, it may be that miglitol exerts, in addition to a delay of intestinal carbohydrate absorption, extraintestinal effects as well, particularly effects on disposition of glucose or anti-insulin counterregulatory factors.

Beneficial effect of low-glycemic index diet in overweight NIDDM subjects

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.

Does a dose of 40 micrograms/day prostaglandin E1 reduce creatinine clearance in a patient with diabetic nephropathy of the nephrotic type?

The case history of a woman, who at the age of 25 years on the birth of her second child was found to be diabetic, is reported. Over the subsequent 30 years the patient had been treated with insulin, the dose administered being monitored at regular intervals. At the age of 52 years, the patient was diagnosed as suffering from hypertension and diabetic nephropathy of the nephrotic type. The patient's condition gradually deteriorated and at 55 years of age 40 micrograms/day prostaglandin E1 was given intravenously for 84 days. Treatment resulted in a decline in urinary protein without a reduction in creatinine clearance. Renograms confirmed an improvement in the vascular and secretory phases of both kidneys.

Habitual physical activity, aerobic capacity and metabolic control in patients with newly-diagnosed type 2 (non-insulin-dependent) diabetes mellitus: effect of 1-year diet and exercise intervention

The aim of this study was to assess the effects of a 1-year intensified diet and exercise education regimen on habitual physical activity and aerobic capacity in middle-aged, obese patients with newly-diagnosed Type 2 (non-insulin-dependent) diabetes mellitus. In addition, we analysed whether the level and the changes in physical activity and aerobic capacity are related to the metabolic control of diabetes. After a 3-month basic education programme, 78 patients (45 men, 33 women) were randomly placed in an intervention or conventionally treated group. The intervention group received intensified diet education and continuous encouragement to increase physical activity which was monitored using exercise records and questionnaires. Aerobic capacity was assessed by measuring oxygen uptake at anaerobic threshold and at peak exercise. The proportion of patients with regular recreational exercise increased from 24% to 38% in the intervention men (0.10 less than p less than 0.20), remained at 54% in the conventionally treated men, increased from 53% to 70% in the intervention women (0.10 less than p less than 0.20) and from 31% to 50% (0.10 less than p less than 0.20) in the conventionally treated women. No measurable improvement was found in oxygen uptake in any of the groups. When the groups were combined, HbA1c showed an inverse correlation with oxygen uptake at anaerobic threshold (r = 0.27, p less than 0.01) and maximum oxygen uptake (r = 0.28, p less than 0.01) at 12 months.(ABSTRACT TRUNCATED AT 250 WORDS)

[Dietary treatment of diabetes mellitus. Background and rationale for recommendations in the 1990's]

Individual dietary regulation is still an important part of all forms of treatment of diabetes. In insulin dependent diabetes (IDDM) it is rational to advise the patient 1) to arrange his diet so that this results in a low glycaemic response, which implies a relatively high intake of dietary fibre and polysaccharides, 2) to distribute the food into 5-6 daily meals and 3) to consume a low-fat diet. This prevents too pronounced postprandial hyperglycaemia and hypoglycaemia between meals. Simultaneously, insulin sensitivity is increased and not only the insulin requirement but also peripheral hyperinsulinism tend to be reduced. Dietary regulation in IDDM is thus a compensation for the defective synchronization of variations in the plasma levels of glucose and insulin in the present day forms of insulin therapy. Nine out of ten diabetic patients are non-insulin dependent (NIDDM). The great majority are obese, 50% have essential hypertension and just as many have dyslipidaemia (raised serum triglyceride and reduced serum high density lipoprotein (HDL)-cholesterol). The condition is characterized pathophysiologically by insulin resistance in muscle, fat and liver tissue and delayed and frequently reduced glucose-stimulated secretion of insulin. The most important element in dietary regulation in NIDDM is, therefore, reduction of the energy content of the food with the object of achieving and maintaining reduction in weight. Even moderate reduction, in the majority of NIDDM patients, will have the effect that metabolism of carbohydrates and lipids becomes approximately normal on account of considerable increase in insulin sensitivity and to a lesser degree increased secretion of insulin.(ABSTRACT TRUNCATED AT 250 WORDS)

[Treatment of non-insulin dependent diabetes (type 2 diabetes mellitus)]

Type 2 diabetes mellitus is characterized by impaired insulin release and sensitivity, elevated blood sugar and unfavourable changes in blood lipids. Insulin resistance and adverse blood lipids are also seen in the state of essential hypertension (the metabolic syndrome). Patients should learn to measure their own blood sugar. Treatment usually begins with regulation of the diet for 3-6 months. If this treatment fails, the next step is to give oral antidiabetic agents. Insulin treatment is required 1) when blood sugar is excessively high; 2) when oral agents fail; and 3) in case of increased need of insulin due to intercurrent disease. Antihypertensive treatment should not have adverse metabolic effects in patients with type 2 diabetes.

Dietary recommendations for people with diabetes: an update for the 1990s. Nutrition Subcommittee of the British Diabetic Association's Professional Advisory Committee

The broad principles of the 1982 British Diabetic Association dietary recommendations remain valid. For the overweight, reduction in energy intake remains the most important aim. Carbohydrate should make up about 50-55% of the dietary energy intake, the majority of this coming from complex sources, preferably foods naturally high in dietary fibre or hydrolysis resistant starch. Up to 25 g of added sucrose may be allowed, provided it is part of a diet low in fat and high in fibre, and that it substitutes for an isocaloric amount of fat or high glycaemic index food or other nutritive sweeteners. Some high-carbohydrate diets have been shown to worsen blood glucose control and serum lipid abnormalities. Some previous recommendations for fibre intake have proved unrealistically high and of limited value. A modest increase to 30 g day-1, concentrating on soluble fibre, is recommended. Reduction of fat intake to 30-35% of energy intake remains an important goal which should help to reduce the incidence of cardiovascular disease in people with diabetes and aid weight loss. Of this only 10% of total energy should be saturated fat, 10% polyunsaturated fat, and 10-15% may be mono-unsaturated fat. The latter has been shown to provide a useful alternative energy source which may have beneficial effects on blood glucose control and serum lipids. Cholesterol intake should not exceed 300 mg day-1. Protein should comprise about 10-15% of energy intake. Reduction in intake of protein and associated nutrients may help to slow down progression of nephropathy. Limitation of salt intake to 6 g day-1 is recommended. Reduction in fat intake may be relatively more important in Type 2 diabetic patients, whereas limitation in protein intake may be more important in Type 1 diabetes.

Diabetes care in health maintenance organizations

An increasing amount of health care today is directed to the amelioration of chronic diseases for which there are no cures. Technological advances and the aging of the population have increased the costs of that care. In an attempt to control costs and increase the efficiency of health care, it is being increasingly delivered in alternate health-care systems where third-party payors influence the access, use, and quality of that care. This article traces the history of the development of alternative health-care delivery systems and describes how they attempt to deal with the tension between cost and quality in the context of the delivery of health care to people with diabetes. Systems for home health care, health education and dietary counseling, prescriptions and durable medical equipment, medical technology assessment, quality management, peer review, and cost containment in the various alternative health-care settings are described. Theoretically, the health maintenance organization offers an ideal system for delivering care that is accessible, affordable, and of good quality.

Diabetic diets and nutritional recommendations: what happens in real life?

Prospective 7-day estimated weight food records were computer analysed in 92 diabetic patients, 45 men and 47 women, 25 with Type 1 and 67 Type 2 diabetes, attending a hospital-based diabetic clinic. The nutrient intakes were compared with a national survey in non-diabetic British adults (OPCS) and the current EASD recommendations for the diabetic diet. Only three diabetic patients achieved the recommended 50-60% energy intake as carbohydrate, four achieved less than 30% energy as fat, one patient less than 10% saturated fat and 20 ate greater than 30 g fibre per day. The overall nutrient intakes of these diabetic patients reflected those of non-diabetic subjects except for a greater intake of protein and smaller intakes of sugar and alcohol. These findings reinforce the problems currently faced in achieving the present recommendations for the diabetic diet.

Relationship between blood pressure and in vivo action of insulin in type II (non-insulin-dependent) diabetic subjects

In nondiabetic hypertensive subjects, a relationship has been found between insulin resistance and level of blood pressure. Since type II (non-insulin-dependent) diabetic subjects are often both insulin-resistant and hypertensive, we studied the relationship between insulin resistance and blood pressure level in a group of patients with type II diabetes. Fourteen women and 19 men with diabetes for 2 to 14 (mean, 7.4) years, treated with diet alone (five subjects) or combined with hypoglycemic agents, were studied. Their average hemoglobin A1c (HbA1c) levels during the study period were 6.6% to 11.7% (mean, 8.6%), and their body mass indexes (BMI) were 20.8 to 33.1 (mean, 26.3) kg/m2. Insulin sensitivity was measured using the hyperinsulinemic, euglycemic glucose clamp technique, and an insulin-sensitivity index was calculated as the ratio of the glucose disposal rate (GDR) to the insulin concentration during clamp (GDR/I). The average of three to eight measurements of diastolic blood pressure (DBP) during the study period (9 to 24 months) in each subject was 79 to 111 (mean, 95.1) mm Hg, and DBP also showed significant correlations to BMI (r = .54) and fasting C-peptide level (r = .38). In a multiple regression model, GDR/I, antihypertensive treatment, and known duration of diabetes were significant and independent predictors of variations in blood pressure, and GDR/I could account for 35% of the observed variations in DBP. We conclude that, in accordance with what has been found in nondiabetic hypertensives, DBP correlates significantly to insulin resistance in type II diabetic subjects.

Polyunsaturated fatty acids may impair blood glucose control in type 2 diabetic patients

Fifteen patients with Type 2 diabetes were given two diets rich in either saturated fat or polyunsaturated fat in alternate order over two consecutive 3-week periods on a metabolic ward. Both diets contained the same amount of fat, protein, carbohydrates, dietary fibre, and cholesterol. The proportions of saturated, monounsaturated and polyunsaturated fatty acids in the saturated fat diet were 16, 10, and 5%-energy and in the polyunsaturated fat diet (PUFA) 9, 10, and 12%-energy. The PUFA diet contained a high proportion of n-3 fatty acids. Metabolic control improved significantly in both dietary periods, due to both qualitative dietary changes and a negative energy balance. The serum lipoprotein concentrations decreased on both diets but the serum lipids were significantly lower after the PUFA diet (serum triglycerides -20%, p = 0.001; serum cholesterol -5%, p = 0.03; VLDL-triglycerides -29%, p less than 0.001; and VLDL-cholesterol -31%, p = 0.001) than after the saturated fat diet. Average blood glucose concentrations during the third week were significantly higher fasting (+15%, p less than 0.01), and during the day at 1100 h (+18%, p less than 0.001) and 1500 h (+17%, p = 0.002) on PUFA than on the saturated fat diet. Significantly higher blood glucose levels were also recorded with a standard breakfast, while the sum of the insulin values was lower (-19%, p = 0.01). HbA1c did not differ significantly between the two dietary periods.(ABSTRACT TRUNCATED AT 250 WORDS)

A comparison of the predictive power for overall blood glucose control of a 'good' fasting level in type 2 diabetic patients on diet alone or with oral agents

The European NIDDM Policy Group classifies both fasting and post-prandial blood glucose concentrations into 'good', 'acceptable', and 'poor' categories. The aim of the present study was to evaluate whether a 'good' fasting blood glucose concentration in Type 2 diabetic patients on diet or diet + oral hypoglycaemic agents is able to predict 'good' blood glucose values throughout the day, and therefore to discover whether or not it is necessary to perform blood glucose profiles in Type 2 diabetic patients when their fasting value is 'good'. Capillary blood glucose profiles (n = 417) were measured in 287 Type 2 diabetic patients, on diet alone (279 profiles), or on diet + tablets (138 profiles). We observed that 66% of profiles on diet and 44% of profiles on diet + tablets had only 'good' blood glucose concentrations (p less than 0.001). Eleven percent of profiles on diet and 30% of profiles on diet + tablets included 'poor' blood glucose concentrations (p less than 0.001). Despite matched fasting blood glucose concentrations (diet 5.69 +/- 0.04 (+/- SE) vs tablets 5.75 +/- 0.05 mmol l-1), levels were higher in the diet + tablet treated patients at all later time-points (p less than 0.01-0.001). HbA1c was significantly higher in tablet-treated patients than in patients on diet alone (6.6 +/- 0.1 vs 5.9 +/- 0.1%, p less than 0.001), and correlated with the mean blood glucose concentration (r = 0.43, p less than 0.001) but not with the fasting glucose concentrations.(ABSTRACT TRUNCATED AT 250 WORDS)

Lack of change of lipoprotein (a) concentration with improved glycemic control in subjects with type II diabetes

Recently, lipoprotein (a) [Lp(a)] has been identified as a major risk factor for coronary heart disease. No data are available on the effect of improved metabolic control on plasma Lp(a) concentrations in subjects with type II diabetes mellitus, a group at high risk for coronary heart disease. We examined the effects of improved metabolic control on plasma lipid and lipoproteins and Lp(a) concentrations in 12 subjects before and after 21 days of tight metabolic control. Glycosylated hemoglobin declined from 8.9% to 6.9% (P less than .002). Lp(a) increased slightly from 21.4 to 25.8 mg/dL (P = .119) with improved metabolic control. There were no significant differences in total, low-density, or high-density cholesterol values, although the decline in triglyceride concentrations was statistically significant. The distribution of apolipoprotein (a) [apo (a)] isoforms in subjects with type II diabetes mellitus was not unusual and the apo (a) isoform patterns did not change with improved metabolic control. Although the number of subjects was small, there was no decline in Lp(a) concentrations with improved control and thus the effect of glycemic control on Lp(a) concentrations may be much smaller in type II than in type I diabetes. These results suggest that diabetic subjects with elevated Lp(a) concentrations should have intensive management of conventional cardiovascular risk factors such as high-density lipoprotein cholesterol (HDLC), low-density lipoprotein cholesterol (LDLC), and blood pressure.