Effects of monounsaturated vs. saturated fat on postprandial lipemia and adipose tissue lipases in type 2 diabetes

BACKGROUND

The effects of different dietary fatty acids on postprandial lipid metabolism in type 2 diabetic patients are still debated.

AIM

To evaluate the effects of monounsaturated (MUFA) vs. saturated fat (SAFA)-rich diets on postprandial lipemia and adipose tissue lipoprotein lipase (LPL), and hormone-sensitive lipase (HSL) in type 2 diabetes.

MATERIALS AND METHODS

Eleven type 2 diabetic patients followed, in random order, a diet rich in MUFA (SAFA 8%, MUFA 23%) and another rich in SAFA (SAFA 17%, MUFA 15%) for a period of 3 weeks each. At the end of the two diets, a standard fat-rich meal was administered and subcutaneous fat biopsies were performed at fasting and 6h after the test meal.

RESULTS

Neither diet induced significant changes in meal lipid tolerance, except for a faster (at 2h) increase in chylomicron triglycerides and a significant decrease in small VLDL triglyceride incremental area after the MUFA diet (-13.6+/-4.7 mg/dl*6h vs. -2.2+/-3.7 mg/dl*6h, p<0.005) (M+/-SEM). LPL and HSL activities were significantly increased after the MUFA diet.

CONCLUSIONS

A MUFA-rich diet reduces postprandial small VLDL triglycerides in type 2 diabetic patients compared to a SAFA-rich diet, and modifies lipolytic enzymes in adipose tissue.

Role of glycemic index and glycemic load in the healthy state, in prediabetes, and in diabetes

The choice of carbohydrate-rich foods in the habitual diet should take into account not only their chemical composition but also their ability to influence postprandial glycemia (glycemic index). Fiber-rich foods generally have a low glycemic index (GI), although not all foods with a low GI necessarily have high fiber content. Several beneficial effects of low-GI, high-fiber diets have been shown, including lower postprandial glucose and insulin responses, an improved lipid profile, and, possibly, reduced insulin resistance. In nondiabetic persons, suggestive evidence is available from epidemiologic studies that a diet based on carbohydrate-rich foods with a low-GI, high-fiber content may protect against diabetes or cardiovascular disease. However, no intervention studies have so far evaluated the potential of low-GI, high-fiber diets to reduce the risk of diabetes, although in studies aimed at diabetes prevention by lifestyle modifications, an increase in fiber consumption was often part of the intervention. In relation to prevention of cardiovascular disease, intervention studies evaluating the effect of a low-GI diet on clinical events are not available; moreover, the results of the few available intervention studies evaluating the effects of GI on the cardiovascular disease risk factor profile are not always concordant. The best evidence of the clinical usefulness of GI is available in diabetic patients in whom low-GI foods have consistently shown beneficial effects on blood glucose control in both the short-term and the long-term. In these patients, low-GI foods are suitable as carbohydrate-rich choices, provided other attributes of the foods are appropriate.

Dietary fat, insulin sensitivity and the metabolic syndrome

Insulin resistance is the pathogenetic link underlying the different metabolic abnormalities clustering in the metabolic syndrome. It can be induced by different environmental factors, including dietary habits. Consumption of energy-dense/high fat diets is strongly and positively associated with overweight that, in turn, deteriorates insulin sensitivity, particularly when the excess of body fat is located in abdominal region. Nevertheless the link between fat intake and overweight is not limited to the high-energy content of fatty foods; the ability to oxidize dietary fat is impaired in some individuals genetically predisposed to obesity. Insulin sensitivity is also affected by the quality of dietary fat, independently of its effects on body weight. Epidemiological evidence and intervention studies clearly show that in humans saturated fat significantly worsen insulin-resistance, while monounsaturated and polyunsaturated fatty acids improve it through modifications in the composition of cell membranes which reflect at least in part dietary fat composition. A recent multicenter study (KANWU) has shown that shifting from a diet rich in saturated fatty acids to one rich in monounsaturated fat improves insulin sensitivity in healthy people while a moderate alpha-3 fatty acids supplementation does not affect insulin sensitivity. There are also other features of the metabolic syndrome that are influenced by different types of fat, particularly blood pressure and plasma lipid levels. Most studies show that alpha-3 fatty acids reduce blood pressure in hypertensive but not in normotensive subjects while shifting from saturated to monounsaturated fat intake reduces diastolic blood pressure. In relation to lipid abnormalities alpha-3 fatty acids reduce plasma triglyceride levels but in parallel, increase LDL cholesterol. Substitution of unsaturated fat for saturated fat not only reduces LDL cholesterol but contributes also to reduce plasma triglycerides in insulin resistant individuals. In conclusion, there is evidence available in humans indicating that dietary fat quality influences insulin sensitivity and associated metabolic abnormalities. Therefore, prevention of the metabolic syndrome has to be targeted: (1) to correct overweight by reducing the energy density of the habitual diet (i.e., fat intake) and (2) to improve insulin sensitivity and associated metabolic abnormalities through a reduction of dietary saturated fat, partially replaced, when appropriate, by monounsaturated and polyunsaturated fats.

Effects of short-chain fructo-oligosaccharides on glucose and lipid metabolism in mild hypercholesterolaemic individuals

BACKGROUND

The intake of 10 g/day of short-chain-fructo-oligosaccharides (sc-FOS) has been shown to increase significantly bifidus counts and to produce high amounts of short-chain fatty acids (SCFA), presumed to influence glucose and lipid metabolism.

AIM

To evaluate the effects of moderate intake of sc-FOS on glucose and lipid metabolism in individuals with mild hypercholesterolaemia.

DESIGN

A randomized double-blind sequential cross-over study.

SUBJECTS AND METHODS

Thirty subjects of both genders (20 M/10 F), mean age 45.5+/-9.9 years (M+/-SD), BMI 26.6+/-2.2 kg/m(2), with plasma cholesterol >5.17 and <7.76 mmol/l and plasma triglycerides <3.45 mmol/l, participated in the study. The study was performed after a wash-out period of 1 month and a run-in period of 1 month to stabilize patients on a standard diet (CHO 50%, fat 30%, protein 20%, fibre 20 g/day) plus placebo (maltodextrine plus aspartame 15 g/day). At the end of run-in, subjects were randomly assigned to receive sc-FOS (Actilight) (10.6g/day) or placebo (maltodextrine plus aspartame 15 g/day) with tea and/or coffee for a duration of 2 months and thereafter switched to the other treatment for additional 2 months. Plasma glucose, total and lipoprotein (VLDL, LDL, HDL) cholesterol and triglyceride concentrations were measured in the fasting state at the end of run-in and of each treatment period. At the end of the two treatment periods, patients consumed a standard test meal (protein 15%, carbohydrate 34%, fat 51%, kJ 3988) 1h after the administration of 5.3g of sc-FOS or placebo; plasma glucose, insulin, free fatty acid (FFA) and triglyceride responses to the test meal were evaluated.

RESULTS

No significant difference in fasting parameters was detected between the two treatments. After sc-FOS and placebo plasma cholesterol levels were, respectively, 6.47+/-0.70 and 6.44+/-0.78 mmol/l (n.s.) and plasma triglycerides were 1.53+/-0.71 and 1.56+/-0.53 mmol/l (n.s.). No significant differences were observed in cholesterol and triglyceride content of VLDL, LDL and HDL and in plasma Apo A1 levels; conversely, fasting plasma Lp(a) concentrations were significantly increased after sc-FOS (37+/-38 vs. 33+/-35 mg/dl; P<0.005). Postprandial responses of glucose, FFA and triglycerides were not significantly different between sc-FOS and placebo, while postprandial insulin response (incremental area) was significantly reduced after sc-FOS compared to placebo (14,490+/-7416 vs. 17,760+/-7710 pmol/l x 300 min; P<0.02).

CONCLUSIONS

A moderate intake of sc-FOS has no major effects on lipid metabolism, both in the fasting and in the postprandial period, in individuals with mild hypercholesterolaemia. A small but significant increase of Lp(a) concentrations was observed with sc-FOS consumption together with a reduction of the postprandial insulin response; however, the clinical relevance of these small effects is unclear.

Insulin sensitivity is increased and fat oxidation after a high-fat meal is reduced in normal-weight healthy men with strong familial predisposition to overweight

OBJECTIVE

To evaluate whether postprandial abnormalities of energy expenditure and/or lipid oxidation are present in healthy, normal-weight subjects with a strong family history of obesity and thus at high risk to become obese.

DESIGN

Case-control study.

SUBJECTS

A total of 16 young healthy men participated in the study. Eight subjects had both parents overweight (father's and mother's body mass index (BMI) >25 kg/m(2)) and eight had both parents with normal body weight (father's and mother's BMI<25 kg/m(2), respectively). The group of subjects with overweight parents was similar to that with normal-weight parents (control group) in terms of BMI (23.7+/-1.7 vs 22.7+/-1.1 kg/m(2)) (M+/-s.d.) and fat-free body mass (FFM) (60.5+/-4.9 vs 58.4+/-2.0 kg), but was slightly older than the control group (25.4+/-3.3 vs 22.7+/-2.4 y; P<0.05).

MEASUREMENTS

Energy expenditure (EE) was measured by indirect calorimetry, and blood samples were taken for the evaluation of metabolic variables in the fasting state and every hour for 8 h after a standard fat-rich meal (protein 15%, carbohydrate 34%, fat 51%, 4090 kJ).

RESULTS

: Fasting plasma glucose, cholesterol, HDL-cholesterol, triglyceride, free fatty acid (FFA) and leptin concentrations were similar in both groups of participants, but subjects with overweight parents has significantly lower plasma insulin concentrations (5.11+/-0.51 vs 7.07+/-1.56 microU/ml; P<0.007) and HOMA index of insulin resistance (1.1+/-0.1 vs 1.6+/-0.4; P<0.01). Postprandial plasma glucose, triglyceride, FFA and leptin concentrations were similar in the two groups, whereas insulin levels were significantly lower in the group with both parents overweight at 3, 5, 6, 7 and 8 h. Fasting and postprandial EE, and fasting lipid and carbohydrate oxidation were similar in both groups. On the contrary, postprandial carbohydrate oxidation (incremental area under curve) was significantly higher (196.25+/-94.75 vs 75.88+/-74.72 mg/kg FFM x 8 h; P<0.007) and that of lipid oxidation lower (90.93+/-80.32 vs 163.68+/-108.22 mg/kg FFM x 8 h; P<0.05) in the group of subjects with overweight parents.

CONCLUSION

Normal-weight subjects with a strong family history of obesity present a reduced lipid oxidation in the postprandial period and a metabolic profile characterized by low plasma insulin levels and the HOMA index, which is compatible with increased insulin sensitivity. These metabolic characteristics may be considered as early predictors of weight gain and are probably genetically determined.

Effects of different dairy products on postprandial lipemia

BACKGROUND AND AIM

To evaluate the effects on postprandial lipemia (PPL), of three fat rich meals, with similar composition but different physical structure (liquid, semisolid and solid).

METHODS AND RESULTS

Eight type 2 diabetic patients of both genders (6M/2F), age 51+/-9 yrs (M+/-SD), BMI 29+/-3 kg/m2, with fasting plasma glucose levels 145+/-24 mg/dL, cholesterol 200+/-38 mg/dL and triglyceride 110+/-45 mg/dL. Participants consumed in the morning, after a 12-hour fast and at 1-week intervals, three test meals with similar volume and composition [protein 36 g, lipid 30 g, carbohydrate 115 g, energy 3556 kJ (850 Kcal)] but with the main source of fat represented by foods with different physical structure (milk, mozzarella-cheese, butter). Each patient underwent gastric emptying measurements by echography; plasma FFA, triglycerides, glucose and insulin were evaluated at baseline and every hour for six hours after each meal. Fasting plasma glucose, cholesterol and triglyceride concentrations were similar at the baseline of the three test meals. Average increases in postprandial plasma triglyceride levels after butter (88+/-8 mg/dL) and mozzarella-cheese (104+/-56 mg/dL) were not different than after milk (98+/-53 mg/dL). The plasma triglyceride peak was also similar after the three test meals but peak time after butter (315+/-42 min; p<0.01) and mozzarella-cheese (277+/-31 min; p<0.02) was significantly delayed compared to milk (225+/-28 min). Gastric emptying rate was similar after butter and milk (14+/-2, 13+/-6 mL/h) and significantly faster after mozzarella-cheese (18+/-5 mL/h; p<0.03).

CONCLUSIONS

While the physical structure of fat-rich foods has no major effect on postprandial plasma triglyceride concentrations, it is able to influence the timing of triglyceride peak; gastric emptying time does not play a major role in modulating the postprandial response of triglycerides and glucose.

Insulin sensitivity is increased and fat oxidation after a high-fat meal is reduced in normal-weight healthy men with strong familial predisposition to overweight

OBJECTIVE

To evaluate whether postprandial abnormalities of energy expenditure and/or lipid oxidation are present in healthy, normal-weight subjects with a strong family history of obesity and thus at high risk to become obese.

DESIGN

Case-control study.

SUBJECTS

A total of 16 young healthy men participated in the study. Eight subjects had both parents overweight (father's and mother's body mass index (BMI) >25 kg/m(2)) and eight had both parents with normal body weight (father's and mother's BMI<25 kg/m(2), respectively). The group of subjects with overweight parents was similar to that with normal-weight parents (control group) in terms of BMI (23.7+/-1.7 vs 22.7+/-1.1 kg/m(2)) (M+/-s.d.) and fat-free body mass (FFM) (60.5+/-4.9 vs 58.4+/-2.0 kg), but was slightly older than the control group (25.4+/-3.3 vs 22.7+/-2.4 y; P<0.05).

MEASUREMENTS

Energy expenditure (EE) was measured by indirect calorimetry, and blood samples were taken for the evaluation of metabolic variables in the fasting state and every hour for 8 h after a standard fat-rich meal (protein 15%, carbohydrate 34%, fat 51%, 4090 kJ).

RESULTS

Fasting plasma glucose, cholesterol, HDL-cholesterol, triglyceride, free fatty acid (FFA) and leptin concentrations were similar in both groups of participants, but subjects with overweight parents has significantly lower plasma insulin concentrations (5.11+/-0.51 vs 7.07+/-1.56 microU/ml; P<0.007) and HOMA index of insulin resistance (1.1+/-0.1 vs 1.6+/-0.4; P<0.01). Postprandial plasma glucose, triglyceride, FFA and leptin concentrations were similar in the two groups, whereas insulin levels were significantly lower in the group with both parents overweight at 3, 5, 6, 7 and 8 h. Fasting and postprandial EE, and fasting lipid and carbohydrate oxidation were similar in both groups. On the contrary, postprandial carbohydrate oxidation (incremental area under curve) was significantly higher (196.25+/-94.75 vs 75.88+/-74.72 mg/kg FFM x 8 h; P<0.007) and that of lipid oxidation lower (90.93+/-80.32 vs 163.68+/-108.22 mg/kg FFM x 8 h; P<0.05) in the group of subjects with overweight parents.

CONCLUSION

Normal-weight subjects with a strong family history of obesity present a reduced lipid oxidation in the postprandial period and a metabolic profile characterized by low plasma insulin levels and the HOMA index, which is compatible with increased insulin sensitivity. These metabolic characteristics may be considered as early predictors of weight gain and are probably genetically determined.

Glycemic index of local foods and diets: the Mediterranean experience

The Mediterranean diet is a healthful eating pattern associated with the prevention of coronary heart disease (CHD). Its main features are moderate intake of total fat (predominantly monounsaturated fat), low consumption of saturated fat and cholesterol-rich foods, and high intake of starch. Although this type of diet has beneficial effects on lipid metabolism, its high carbohydrate content might not be ideal for patients with diabetes or other conditions associated with insulin resistance (e.g., metabolic syndrome), who are known to be at particular risk of CHD. We therefore evaluated the glycemic response to starchy foods based on wheat (typical of the Italian diet) in patients with type 2 diabetes and identified certain characteristics of foods explaining their effects on postprandial glucose response. We found that spaghetti and potato dumplings, because of their low blood glucose response, represent a valid alternative to other starchy foods typical of the Mediterranean diet. Food structure plays an important role in determining the accessibility of starch to digestion, thus influencing the postprandial blood glucose response, which modulates plasma insulin and lipid levels.

Dietary fibre in treatment of diabetes: myth or reality?

Diabetes is a plurimetabolic disease characterised mainly by glucose metabolism abnormalities that lead to the development of acute and long-term complications. Long-term complications are rapidly increasing, which explains the higher mortality due to cardiovascular events in diabetic patients compared to the general population. A poor blood glucose control is known to be an important risk factor for the development of cardiovascular complications, and dietary fibre - particularly the soluble type - plays an important role in controlling plasma glucose concentrations and other risk factors associated with diabetes. Nevertheless, there are still some doubts as to whether it is possible to achieve, in free-living diabetic patients, good compliance to a high fibre diet without using fibre supplements or foods fortified with fibre, and whether the beneficial effects of this diet on blood glucose control, observed in acute or in medium-term studies, are clinically relevant also in the longterm. Recently, a wealth of convincing evidence has confirmed the hypothesis that, in diabetic patients, dietary fibre decreases postprandial plasma glucose, insulin and triglyceride concentrations, and has a clinically relevant hypocholesterolaemic effect. These data also show that: 1) it is possible to increase dietary fibre by consuming exclusively natural foods, with a satisfactory compliance in free-living diabetic patients also in the long-term, due to its minimal side-effects; and 2) the beneficial metabolic effects of dietary fibre are long-lasting and clinically relevant, as shown by the lower plasma glycosylated haemoglobin levels, reduced rate of hypoglycaemic episodes and improved cardiovascular profile both in type 1 and type 2 diabetic patients.

The BRAVO project: screening for childhood obesity in a primary school setting

BACKGROUND AND AIM

The prevalence of childhood obesity is increasing worldwide, raising a number of public health concerns. First, childhood obesity is a strong predictor of adult obesity; second, the low long term success rate and the high social cost of the treatment of obesity suggest that attention should be paid to the prevention of obesity early in childhood. The objective of the present study was to evaluate dietary habits and anthropometric factors in a sample of schoolchildren aged 6-12 years living in Southern Italy in the framework of an ongoing prospective study aimed at childhood obesity prevention.

METHODS AND RESULTS

The BRAVO Project is carried out in co-operation with the school staff and is a part of an educational program on nutrition for the schoolchildren and their families. During the first phase of the study, the prevalence of overweight and obesity was evaluated in 363 children adopting the criteria for definition of childhood obesity recently proposed by the International Obesity Task Force (IOTF). The main result of this study was that in our cohort an exceedingly high risk of becoming overweight in adult age was observed for any one-year age class.

CONCLUSIONS

The results of the present study confirmed the trend toward an increasing prevalence of childhood obesity observed in other Western countries. Moreover, out data--though preliminary--suggest that the large scale involvement of primary school in screening programs could represent an effective preventive strategy against the increased risk of childhood obesity.

Characteristics of some wheat-based foods of the Italian diet in relation to their influence on postprandial glucose metabolism in patients with type 2 diabetes

The present study was aimed at evaluating in patients with type 2 diabetes: (1) the glycaemic response to four starchy foods based on wheat, typical of the Italian diet; (2) the importance of some food characteristics in relation to their effects on postprandial glucose response. Seventeen patients with type 2 diabetes (eleven men and six women) participated in the study. All patients consumed, in random order and on alternate days, 50 g available carbohydrate provided by 90 g white bread and, according to a randomised procedure, an equivalent amount of carbohydrate provided by one (n 8) or two (n 9) of three other different test foods (g): pizza 85, potato dumplings 165, hard toasted bread 60. Foods had a similar nutrient composition. Plasma glucose response, measured for 180 min, was significantly lower after the potato dumplings than after white bread at 90 (P < 0.05), 120 (P < 0.01), and 150 (P < 0.05) min. No difference was observed in postprandial plasma insulin response after the various test foods. The percentage of starch hydrolysed after 5 h in vitro hydrolysis with alpha-amylase was about 30 % lower for potato dumplings than for the other foods. However, no differences in the resistant starch content, the rate of diffusion of simple sugars added to a dialysis tube containing the food, and the viscosity of digesta were observed among the test foods. Scanning electron microscopy of potato dumplings showed a compact structure compatible with impaired accessibility of starch to digestive enzymes. In conclusion, carbohydrate-rich foods typical of the Italian diet which are often consumed as an alternative to pasta dishes are not equivalent in terms of metabolic impact in diabetic patients. Due to their low blood glucose response, potato dumplings represent a valid alternative to other starchy foods in the diabetic diet. Food structure plays an important role in determining starch accessibility to digestion, thus influencing the postprandial blood glucose response.

Long-term dietary treatment with increased amounts of fiber-rich low-glycemic index natural foods improves blood glucose control and reduces the number of hypoglycemic events in type 1 diabetic patients

OBJECTIVE

To evaluate in type 1 diabetic patients 1) the long-term feasibility of a high-fiber (HF) diet composed exclusively of natural foodstuffs and 2) the efficacy of this diet in relation to blood glucose control and incidence of hypoglycemic episodes.

RESEARCH DESIGN AND METHODS

The study was randomized with parallel groups. Participants were part of a larger multicenter study on the effects of acarbose on glucose control in diabetes. A total of 63 type 1 diabetic patients, age 28 +/- 9 years, BMI 24 +/- 0.6 kg/m2, after a 4-week run-in period on their habitual diet, were randomized to either an HF (n = 32) or a low-fiber (LF) diet (n = 31) for 24 weeks. The two diets, composed exclusively of natural foodstuffs, were weight-maintaining and, aside from their fiber content, were similar for all nutrients. At the end of the run-in period and the dietary treatment, fasting blood samples for the measurement of plasma cholesterol, HDL cholesterol, triglyceride, and HbA(1c) were collected. A daily glycemic profile was performed on a day in which the participants had consumed a standard menu representative of their treatment diet (HF or LF).

RESULTS

Of the 63 study subjects, 29 in the HF group (91%) and 25 in the LF group (81%) completed the study Compared with the LF diet, the HF diet after 24 weeks decreased both mean daily blood glucose concentrations (P < 0.05) and number of hypoglycemic events (P < 0.01). When compliance to diet was taken into account, 83% of the subjects on the HF diet and 88% on the LF diet were compliant. In this subgroup, compared with the LF diet, the HF diet significantly reduced mean daily blood glucose concentrations (P < 0.001), HbA(1c) (P < 0.05), and number of hypoglycemic events (P < 0.01).

CONCLUSIONS

In type 1 diabetic patients, an HF diet is feasible in the long term and, compared with an LF diet, improves glycemic control and reduces the number of hypoglycemic events.

Efficacy and safety of acarbose in the treatment of Type 1 diabetes mellitus: a placebo-controlled, double-blind, multicentre study

AIMS

The aim of the study was to evaluate the efficacy and safety of acarbose in patients with Type 1 diabetes mellitus (DM).

METHODS

A multicentre double-blind, randomized, placebo-controlled study was performed. After a 6-week run-in, 121 patients were randomized to acarbose or placebo and to high- or low-fibre diet for 24 weeks. Acarbose dose was 50 mg t.d.s. for the first 2 weeks and 100 mg t.d.s. for the subsequent weeks.

RESULTS

At the end of 24 weeks of treatment the intention to treat analysis showed that acarbose compared with placebo decreased 2 h postprandial plasma glucose levels (12.23 +/- 0.83 vs. 14.93 +/- 0.87 mmol/l; F = 6.1, P < 0.02) (least square means +/- SEM). No significant effect of acarbose was recorded on HbA1c or on the number of hypoglycaemic episodes. The effect of acarbose on blood glucose control was not influenced by the amount of carbohydrate and/or fibre intake. The incidence of adverse events were 75% and 39% in acarbose and placebo groups, respectively; they were mild and confined to the gastrointestinal tract.

CONCLUSIONS

The use of acarbose in combination with insulin reduces postprandial plasma glucose levels in Type 1 diabetic patients who are not satisfactorily controlled with insulin alone but without significant effect on HbA1c.

Does a high-carbohydrate diet have different effects in NIDDM patients treated with diet alone or hypoglycemic drugs?

OBJECTIVE

To compare the effects of a nigh-carbohydrate diet on blood glucose and plasma lipids in NIDDM patients with either mild or severe glucose intolerance.

RESEARCH DESIGN AND METHODS

A crossover design with a 15-day intervention diet was used. Eighteen patients were separated into two groups on the basis of hypoglycemic treatment (diet, n = 9, or diet plus glibenclamide, n = 9) and were assigned to a 15-day treatment with a high-carbohydrate/low-fiber diet containing 60% energy from carbohydrate and 20% from fat or a low-carbohydrate/low-fiber diet with 40% energy from carbohydrate and 40% from fat and then crossed over to the other diet for 15 more days.

RESULTS

The high-carbohydrate diet produced a significant increase in postprandial blood glucose in patients on glibenclamide (13.6 +/- 1.4 vs. 11.0 +/- 1.8 mmol/l, P < 0.002, while no difference was recorded in the group on diet alone (9.7 +/- vs. 8.9 +/- 0.6 mmol/l). Postprandial insulin levels were significantly higher after the high-carbohydrate diet in the group on diet along (248 +/- 32 vs. 192 +/- 28 pmol/l, P < 0.01), while no significant differences were observed in the other group (226 +/- 19 vs. 202 +/- 24 pmol/l) The high-carbohydrate diet also induced a significant increase in fasting plasma triglyceride concentrations in both groups (1.36 +/- 0.2 vs. 1.12 +/- 0.2 mmol/l, P < 0.05 and 1.4 +/- 0.3 vs. 1.1 +/- 0.1 mmol/l, P < 0.05). No differences were observed in fasting plasma cholesterol and HDL.

CONCLUSIONS

The effects of the high-carbohydrate diet on blood glucose control in NIDDM patients differ according to severity of glucose intolerance.

Effects of changing amount of carbohydrate in diet on plasma lipoproteins and apolipoproteins in type II diabetic patients

Eight type II (non-insulin-dependent) normolipidemic diabetic patients (aged 45 +/- 15 yr, body mass index 22 +/- 2 kg/m2, means +/- SD) treated with diet alone or diet plus oral hypoglycemic agents were given, in random order for periods of 15 days, two diets with different carbohydrate (CHO) (40 vs. 60% of total calories) and fat (20 vs. 40%) levels. Simple CHO, fiber, saturated fat, cholesterol, and polyunsaturated-saturated fat ratio were similar in the two diets. Total plasma cholesterol was not significantly affected by dietary changes; conversely, plasma triglyceride (1.38 +/- 0.59 vs. 1.11 +/- 0.39 mM, P less than 0.05) and apolipoprotein CII (3.8 +/- 1.4 vs. 3.3 +/- 0.8 mg/dl) increased significantly after the high-CHO low-fat diet. Among the various lipoproteins, very-low-density lipoprotein (VLDL) was the most affected by diet: VLDL cholesterol concentrations increased from 0.30 +/- 0.19 to 0.43 +/- 0.28 mM (P less than 0.05), and triglyceride concentrations increased from 0.62 +/- 0.33 to 0.88 +/- 0.53 mM (P less than 0.05). In conclusion, increasing the amount of complex CHO in the diet induces an elevation of VLDL in normolipidemic, nonobese, mildly type II diabetic patients.

Presence of very low density lipoprotein compositional abnormalities in type 1 (insulin-dependent) diabetic patients; effects of blood glucose optimisation

Plasma lipoprotein compositional abnormalities were investigated in eight normolipidaemic (plasma cholesterol less than 5.70 mmol/l; triglyceride less than 2.03 mmol/l) young male Type 1 (insulin-dependent) diabetic patients (before and after a short period of optimised blood glucose control) and in nine healthy control subjects, matched for sex, age and body mass index. Free and esterified cholesterol, triglyceride, phospholipids were assayed in all lipoprotein classes (VLDL, IDL, LDL) and in HDL subclasses (HDL2 and HDL3); apoB was measured only in very low density lipoproteins (VLDL). All VLDL constituents were increased in the diabetic group, the differences being more striking for apoB (6.0 +/- 1.1 mg/dl vs 2.0 +/- 0.1 mg/dl, p less than 0.02), free cholesterol (0.27 +/- 0.04 mmol/l vs 0.13 +/- 0.02 mmol/l, p less than 0.02) and esterified cholesterol (0.32 +/- 0.08 mmol/l vs 0.13 +/- 0.01 mmol/l, p less than 0.05). Also HDL subfractions showed differences between the two groups: all HDL2 constituents were increased, while in HDL3 only triglyceride was significantly increased (0.11 +/- 0.01 mmol/l vs 0.08 +/- 0.004 mmol/l, p less than 0.02). After two weeks of optimised blood glucose control all VLDL constituents were reduced and particularly: esterified cholesterol (-39%, p less than 0.02), free cholesterol (-37%, p less than 0.05), apoB (-35%, p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Different glycaemic responses to pasta, bread, and potatoes in diabetic patients

To evaluate whether the same amount of carbohydrate (CHO) in different foods gives different glycaemic responses when consumed in the context of a real meal, seven diabetic patients were given in a random order and on alternate days three test meals of identical composition. Each meal consisted of a fixed part to which a 50 g CHO portion of either bread (90 g) or spaghetti (65 g) or potatoes (285 g) was added. The glycaemic response was significantly higher after ingestion of bread than after the spaghetti meal both at 2 (5.9 +/- 0.8 vs 4.3 +/- 0.7 mmol/l X hour, p less than 0.05) and at 5 hours (16.5 +/- 3.6 vs 9.8 +/- 2.3 mmol/l X hour, p less than 0.05). The glycaemic response to the potato meal was similar to that for bread at 2 hours (6.2 +/- 1.2 mmol/l X hour, p less than 0.05 vs spaghetti) and intermediate between the two other test meals at 5 hours (14.6 +/- 4.3 mmol/l X hour). Meal planning for diabetic patients should be based not only on the biochemical properties but also on the glycaemic response to the food.