Trans fatty acids consumption in type 1 diabetic patients: evaluation by dietary records and measurement in serum phospholipids.

The consumption of foods containing trans fatty acids (TFA), especially those produced by food industries, induces pleiotropic negative effects on health. Therefore, it is important to assess the amount of TFA consumed, especially in age groups more exposed to the consumption of TFA-containing foods. The present pilot study evaluates TFA intake in 54 young people with and without type 1 diabetes (29 young subjects with type 1 diabetes and 25 healthy subjects) through both dietary records (7-day food record) and the measurement of TFA levels in serum phospholipids, a possibly more objective marker of TFA intake. The comparison between the two groups was made by the student t test for independent samples. The intake of synthetic TFA was low in both groups (type 1 diabetic patients: 0.25 ± 0.25 g/day; healthy subjects 0.48 ± 0.37 g/day), but significantly lower in diabetic patients vs controls (P < 0.05); TFA levels in serum phospholipids also confirmed a low intake of these fatty acids. These data indicate that the intake of trans fatty acids is relatively low in our population, i.e.,<1% of total calories in the diet, in line with what recommended by the World Health Organization.

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.

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.

Peptide T revisited: conformational mimicry of epitopes of anti-HIV proteins.

Peptide T (ASTTTNYT), a fragment corresponding to residues 185-192 of gp120, the coat protein of HIV, is endowed with several biological properties in vitro, notably inhibition of the binding of both isolated gp120 and HIV-1 to the CD4 receptor, and chemotactic activity. Based on previous nuclear magnetic resonance (NMR) studies performed in our laboratory, which were consistent with a regular conformation of the C-terminal pentapeptide, and SAR studies showing that the C-terminal pentapeptide retains most of the biological properties, we designed eight hexapeptides containing in the central part either the TNYT or the TTNY sequence, and charged residues (D/E/R) at the two ends. Conformational analysis based on NMR and torsion angle dynamics showed that all peptides assume folded conformations. albeit with different geometries and stabilities. In particular, peptides carrying an acidic residue at the N-terminus and a basic residue at the C-terminus are characterized by stable helical structures and retain full chemotactic activity. The solution conformation of peptide ETNYTR displays strong structural similarity to the region 19-26 of both bovine pancreatic and bovine seminal ribonuclease, which are endowed with anti-HIV activity. Moreover, the frequent occurrence, in many viral proteins, of TNYT and TTNY, the two core sequences employed in the design of the hexapeptides studied in the present work, hints that the sequence of the C-terminal pentapeptide TTNYT is probably representative of a widespread viral recognition motif.

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.