Alberto Maiz G

Determinación del índice de resistencia insulínica mediante HOMA en una población de la Región Metropolitana de Chile

Background: Insulin resistance is defined as an inappropriate high level of plasma insulin required to maintain metabolic homeostasis. It is associated with type 2 diabetes and cardiovascular diseases. The glucose clamp technique is the standard method for the measurement of insulin resistance. However, this method is laborious, expensive and impractical to perform in epidemiological investigations. The homeostasis model assessment (HOMA) has been proposed to assess insulin resistance and secretion, using fasting glucose and insulin concentrations. Aim: To measure insulin resistance using HOMA (HOMAir) in a population sample from the Metropolitan Region in Chile. Material and Methods: One hundred twenty subjects (59 female) with a normal body mass index and fasting blood glucose were studied. Fasting plasma glucose was measured by a glucose oxidase method and serum insulin was measured by radio immunoassay. Results: Fasting blood glucose was 81.6±9.4 mg/dl and serum insulin was 9.7±2.4 µU/ml. Mean HOMA insulin resistance was 1.96±0.57 (range 0.5 and 3.0). Conclusions: These HOMA values can be used as reference for Chilean non obese individuals (Rev Med Chile 2002; 130: 1227-31)

Ingesta de nutrientes en adultos mayores de la comuna de Providencia, Santiago de Chile

Background: The information available on food intake in the elderly in Chile is restricted to individuals of low socioeconomic groups, but there is no data available on food intake in elderly of higher income groups. Aim: To assess food intake in a group of elderly people from Providencia County in Santiago, a middle income community. Subjects and methods: Forty one subjects (20 male), aged 60 to 73 years, were studied. Trained volunteers applied a 3 days food registry, to determine food intake. Intake was assessed using 1985 FAO/OMS/UNU recommendations for energy intake and USA Food and Nutrition Board recommendations for micronutrient intake. Results: The studied subjects had an adequate macronutrient intake, when compared with current recommendations. There was a relatively low intake of calories from fat (24.6% in males and 26.1% in females). Also, vitamin and mineral intake was adequate with the exception of calcium (64.5% and 57.9% of recommendation in males and in females respectively), zinc and folic acid (74.2% and 62.4% in males and females respectively). The intake of legumes and cereals was relatively low. Conclusions: Food intake in this group of individuals was substantially higher than that reported previously for poor elderly Chileans and similar to that of industrialized countries. Food intake of the elderly is probably related to socioeconomic level (Rev Med Chile 2002; 130: 1335-42)

EL ROL DE LA FIBRA DIETÉTICA EN LA NUTRICION ENTERAL

La fibra dietetica esta constituida por un grupo heterogeneo de sustancias de origen vegetal que son resistentes a la digestion y absorcion en el intestino delgado, pero que sufren una digestion parcial o total en el colon. La fibra insoluble ayuda a mantener un transito intestinal normal y la soluble tiene efectos beneficiosos sobre la microflora del colon donde es fermentada generando acidos grasos de cadena corta (AGCC). Los AGCC son substratos preferenciales para las celulas intestinales. A pesar del conocimiento sobre los efectos beneficiosos de la fibra, las formulas de nutricion enteral (NE) que rutinariamente se indican, no la contienen. Recientemente, se ha incorporado fibra soluble (fructo-oligosacaridos -FOS-) en algunas de estas formulas, siendo ellas de utilidad para el manejo de diarreas en pacientes que reciben NE. Ademas, estas formulas parecen ser utiles en el tratamiento de pacientes con enfermedades intestinales inflamatorias y en el sindrome de intestino corto

Diferencias en antioxidantes plasmáticos según nivel socioeconómico en mujeres chilenas

BACKGROUND Free radical-mediated oxidative damage is a known initial event in atherogenesis. Cardiovascular disease is frequent in the Chilean population showing differences in the prevalence of risk factors of the disease according to socioeconomic level (SEL). AIM To determine levels of antioxidants and lipid peroxides in Chilean women from different SEL. PATIENTS AND METHODS Blood samples were taken from 81 women for measurements of plasma ascorbic acid, beta-carotene, alpha-tocopherol, licopene, ubiquinol, glutathione, total plasma antioxidant capacity, and lipid peroxides (TBARS). RESULTS Individuals in the lower SEL showed reduced levels of plasma beta-carotene, ascorbic acid, alpha-tocopherol, and ubiquinol compared to women in the higher SEL. There were no differences between groups in the plasma levels of glutathione, total antioxidant capacity, or TBARS. CONCLUSIONS The results could be explained in part by the higher consumption of fruits and vegetables in women from the upper SEL.

Mecanismos de contaminación de las fórmulas para nutrición enteral

One of the most frecuent complications of enteral nutrition is formula contamination. The objective of this study was to evaluate the frequency and routes by which enteral formula contamination occurs. Two types of formula were evaluated, one powdered and one liquid, with sterile re-used containers. The results show that the most important way of contamination is in the formula-preparing unit by manipulation or use of contaminated utensils. The utilization of re-used containers contributes to contamination in a lesser degree. The solution administration sets have a high degree of contamination, over 85% and this is not modified by the use of sterile material. Probably there is also a retrograde contamination mechanism.

Cambios en los factores de riesgo metabólicos en pacientes obesos en tratamiento

Background: Obesity is a threaten to health due to its association with cardiovascular risk factors. Aim: To assess the change in metabolic risk factors after weight reduction in obese patients. Patients and methods: A retrospective analysis of 277 obese patients (198 female) aged 39.5±12 years old, that completed a six month treatment period, consisting in a calori restricted diet (800-1200 Kcal/day), physical activity, education and group psychological counseling. At the beginning and at the end of the program, weight, waist circumference, resting energy expenditure (REE), serum lipid profile, plasma glucose and plasma insulin levels were measured. Results: During the treatment period, body mass index decreased from 38±7 to 33.2±6.4 kg/m2 with a weight loss of 11.7 kg, waist circumference decreased from 106.6±14.6 to 93.9±13.5 cm, REE decreased from 1774±383 to 1585±267 Kcal/day, blood glucose fell by 5.8%, plasma insulin fell by 40.4%, total cholesterol fell by 7.5%, LDL cholesterol fell by 8.7%, triglycerides fell by 26.6%, and total cholesterol/HDL ratio fell by 12.2%. Conclusions: Weight loss was associated with improvement in metabolic cardiovascular risk factors in obese patients

Terapia hipolepemiante intensiva en el manejo del riesgo cardiovascular ateroesclerótico

Primary and secondary prevention trials have clearly demonstratedthat lowering serum cholesterol levels with statins reduces the incidence of cardiovascular events.Recent studies plus post hoc analysis of previous clinical trials show that risk reduction isproportional to the magnitude of LDL cholesterol lowering. Therefore, new recommendations ofthe National Cholesterol Education Program (USA) have defined a category of patients with veryhigh cardiovascular risk, who should achieve serum LDL cholesterol levels below 70 mg/dl. Thisproposal will require new and more efficient pharmacologic strategies to attain the increasinglystrict therapeutic goals for LDL cholesterol. This article reviews the clinical studies that support theuse of intensive lipid lowering therapy to reduce cardiovascular risk. An effective reduction ofserum cholesterol can be obtained using statins in high doses or a combination of hypolipidemicdrugs with different mechanisms of action (Rev Med Chile 2006; 134: 641-8).(