La actividad física y el estado nutricional y psicosocial del anciano no dependiente / Physical activity and nutritional and psychosocial status in non-dependent elderly

OBJETIVO: Describir el grado de actividad física (AF) de una muestra de ancianos independientes no institucionalizados y la relación entre aquel y el estado nutricional y las condiciones psicosociales de los ancianos. MATERIAL Y MÉTODOS: Estudio descriptivo transversal multicéntrico implementado en los centros de salud urbanos de la ciudad de Huesca en mayores de 75 años. Tamaño muestral 60 pacientes. Se analizaron variables demográficas, psicosociales, nutricionales, antropométricas y AF. Para la medición de esta última, se utilizó la escala breve de Minnesota en español (VREM). RESULTADOS: La edad media fue de 81,58 años (±4) con una distribución por género del 51,7% mujeres. El grupo mostró globalmente una situación de salud favorable: Afectación física leve (45%), correcta salud mental referida al estado cognitivo (93%) o de ánimo (88%), estado social favorable (96%), independencia para las actividades de la vida diaria (100%) y buena calidad de vida percibida (puntuación>70 en el 70%). En relación con la AF se obtuvo una media de 4666,2MET-min/14 días y se identificaron como sedentarios el 10% de los participantes. Se obtuvo una relación inversa estadísticamente significativa de la AF con la incapacidad funcional, la sarcopenia y la composición corporal (perímetro de cintura, diámetro abdominal sagital, índice de masa y porcentaje de grasa corporales) (p < 0,05). La AF no mostró relación significativa con el estado nutricional y las condiciones psicosociales. Sí resultó significativa la observada entre el estado nutricional y las variables de la esfera psicosocial (p < 0,01). CONCLUSIONES: Las características de la población estudiada en las esferas orgánica, funcional, psíquica y social no sugieren importantes limitaciones para la AF. Un porcentaje nada despreciable de ancianos no realiza suficiente AF. Existe una relación significativa entre la realización de ejercicio físico y los índices de composición corporal favorables

OBJECTIVE: To describe the level of physical activity (PA) of a sample of independent non-institutionalised elderly and its relationship between nutritional status and psychosocial conditions of the elderly. MATERIAL AND METHODS: A multicentre cross-sectional descriptive study carried out in Health Centres of the city of Huesca in a sample size of patients over 75 years-old. Demographic, psychosocial, nutritional, anthropometric, and PA variables were analysed. The short scale of Minnesota in Spanish (VREM) was used to measure the latter. RESULTS: The mean age was 81.58 years (±4) with a gender distribution of 51.7% women. The group were in a good health condition overall: Mild physical impairment (45%), correct mental health as regards cognition (93%) or mood (88%), favourable social status (96%), independence for activities of daily living (100%), and a good perceived quality of life (score>70 in 70%). There was a mean of 4666.2 METS-Min/14 days obtained in PA, and 10% of the participants were identified as sedentary. A statistically significant inverse relationship (P<.05) was observed between PA and functional disability, sarcopenia and body composition (waist circumference, sagittal abdominal diameter, mass index, and body fat percentage). No significant relationship was observed between PA and nutritional status and psychosocial conditions. The relationship between the nutritional status and the variables of the psychosocial sphere was significant (P<.01). CONCLUSIONS: The characteristics of the population studied in the organic, functional, psychical, and social spheres do not suggest important limitations for PA. An insignificant percentage of the elderly does not perform enough PA. There is a significant relationship between physical exercise and favourable body composition rates

[Physical activity and nutritional and psychosocial status in non-dependent elderly]. / La actividad física y el estado nutricional y psicosocial del anciano no dependiente.

OBJECTIVE: To describe the level of physical activity (PA) of a sample of independent non-institutionalised elderly and its relationship between nutritional status and psychosocial conditions of the elderly. MATERIAL AND METHODS: A multicentre cross-sectional descriptive study carried out in Health Centres of the city of Huesca in a sample size of patients over 75 years-old. Demographic, psychosocial, nutritional, anthropometric, and PA variables were analysed. The short scale of Minnesota in Spanish (VREM) was used to measure the latter. RESULTS: The mean age was 81.58 years (±4) with a gender distribution of 51.7% women. The group were in a good health condition overall: Mild physical impairment (45%), correct mental health as regards cognition (93%) or mood (88%), favourable social status (96%), independence for activities of daily living (100%), and a good perceived quality of life (score>70 in 70%). There was a mean of 4666.2 METS-Min/14 days obtained in PA, and 10% of the participants were identified as sedentary. A statistically significant inverse relationship (P<.05) was observed between PA and functional disability, sarcopenia and body composition (waist circumference, sagittal abdominal diameter, mass index, and body fat percentage). No significant relationship was observed between PA and nutritional status and psychosocial conditions. The relationship between the nutritional status and the variables of the psychosocial sphere was significant (P<.01). CONCLUSIONS: The characteristics of the population studied in the organic, functional, psychical, and social spheres do not suggest important limitations for PA. An insignificant percentage of the elderly does not perform enough PA. There is a significant relationship between physical exercise and favourable body composition rates.

Utilidad del cuestionario de sobreingesta alimentaria en la exploracion psicologica previa a la cirugia bariatrica / Utility of the questionnaire of overeating food in psychological exploration prior to bariatric surgery

Introducción: La obesidad mórbida (definida por tener un IMC > 40) suele producir graves problemas para la salud y para la calidad de vida del paciente. En esta población se han estudiado múltiples aspectos psicosociales, sin embargo no se dispone de un estudio en el que se cuantifiquen hábitos, pensamientos y actitudes relacionadas con la obesidad con un instrumento completo como el Cuestionario de Sobreingesta Alimentaria (CSA). Objetivos: Evaluar los hábitos y actitudes del comportamiento alimentario en la obesidad mórbida. Métodos: Se diseña un estudio transversal sobre una muestra de treinta pacientes con obesidad mórbida sin psicopatología asociada que contraindique la cirugía bariátrica, a los que se aplica el Cuestionario de Sobreingesta Alimentaria (CSA). Resultados: Se obtienen puntuaciones elevadas en las escalas de la CSA: ‘Sobreingesta alimentaria’; ‘Antojos alimentarios’; ‘Expectativas relacionadas con comer’; ‘Racionalizaciones’; ‘Subingesta alimentaria’ y ‘Motivación para bajar peso’. Por otra parte, los pacientes presentan puntuaciones bajas en ‘Hábitos de salud’; e ‘Imagen Corporal Positiva’; mientras que puntúan elevado en las escalas de ‘Aislamiento social’ (relativa escasez de recursos personales) y ‘Alteración afectiva’. Discusión y Conclusiones: Tras el análisis de los resultados obtenidos, concluimos que el Cuestionario de Sobreingesta Alimentaria es un instrumento útil y fiable para evaluar las alteraciones disfuncionales en los hábitos y actitudes relacionados con la conducta alimentaria de los pacientes con obesidad mórbida candidatos a cirugía bariátrica (AU)

Background: Morbid obesity (defined by BMI>40) usually causes severe health problems and can also affect the quality of life. Although several psychosocial aspects have been studied in patients with morbid obesity, further research is needed using a complete instrument that measures habits, thoughts and attitudes related to obesity, such as the Overeating Questionnaire (OQ). Objectives: The aim of this study is to assess the habits and attitudes of eating behaviour in a sample of thirty people with morbid obesity. Methods: A cross-sectional study was conducted on a sample of thirty patients with morbid obesity and without any associated psychopathology that contraindicates bariatric surgery, using the Overeating Questionnaire (OQ). Results: Patients scored higher in the ‘Overeating’, ‘Food craving’, ‘Expectations related to eating’, ‘Rationalizations’, ‘Undereating’ and ‘Motivation to lose weight’ OQ scales. In addition, patients’ score decreased in the ‘Health Habits’ and ‘Positive Body Image’ OQ scales, while increased in the ‘Social isolation’ (relative lack of personal resources) and ‘Affective disturbance’ scales. Discussion and Conclusions: After the analysis of the results obtained, we conclude that the Overeating Questionnaire is a useful and reliable tool to assess the dysfunctional alterations in habits and attitudes related to eating behaviour in morbidly obese patients selected for bariatric surgery (AU)

Naturally-occurring phytosterols in the usual diet influence cholesterol metabolism in healthy subjects.

BACKGROUND AND AIMS: Modulation of cholesterol absorption is potentially an effective way of lowering blood cholesterol levels and decreasing inherent cardiovascular risk in the general population. It is well established that cholesterol absorption efficiency can be modified by the intake of foods enriched with gram-doses of phytosterols, but little is known about the effects of phytosterols in the usual diet, even though moderate doses have been reported to affect whole-body cholesterol metabolism. A way to indirectly measure cholesterol synthesis and absorption rates is by quantification of serum non-cholesterol sterols. The aim of this study was to investigate the role of naturally occurring phytosterol intake on cholesterol absorption and serum cholesterol concentrations in a Spanish free-living population. METHODS AND RESULTS: A total of 85 healthy volunteers were studied regarding their dietary habits (using a validated food frequency questionnaire), lipid profile and surrogate markers of cholesterol metabolism. Subjects were classified into tertiles of total phytosterol intake, and differences in lipid profile and markers of cholesterol metabolism were assessed by multivariate linear regression models adjusted for various confounders. The estimated daily intake of phytosterols and cholesterol was 489 (median) and 513 (mean) mg, respectively. Both serum low-density lipoprotein (LDL)-cholesterol concentration and sitosterol-to-cholesterol ratio adjusted by sitosterol intake (a surrogate marker of intestinal cholesterol absorption) decreased significantly (p < 0.05, both) across tertiles of phytosterol intake. CONCLUSION: Moderate doses of phytosterols in the habitual diet might have a protective effect on the lipid profile via decreasing cholesterol absorption.

A moderate intake of phytosterols from habitual diet affects cholesterol metabolism

No disponible

Cholesterol metabolism homeostasis is the result of a balance between synthesis, degradation and intestinal absorption. It is well established that intestinal cholesterol absorption efficiency can be modified by the intake of phytosterol-enriched food and, therefore, have a serum cholesterol-lowering effect. Recent epidemiological and clinical studies have shown that presence of phytosterols at normal diet levels could also be effective on lowering total and LDL serum cholesterol since they affect whole-body cholesterol metabolism even at those moderate doses. The aim of this study was to analyze the effect of the levels of the naturally-occurring phytosterols in the diet on cholesterol metabolism parameters. In order to do that a group of 99 healthy volunteers was studied for their dietary habits and surrogate markers of cholesterol synthesis and absorption. The mean daily dietary intake of phytosterols, measured by a food semiquantitative frequency questionnaire, was found to be 494 mg being beta-sitosterol the major contributor to it. Subjects were classified into tertiles according to their total phytosterol intake and comparisons were done between subgroups. No statistical differences were observed for surrogate markers of intestinal cholesterol absorption, but a significant increase in the cholesterol synthesis surrogate marker lathosterol-to-cholesterol ratio associated to highest dietary phytosterol intake was observed. Regardless of this, only a non significant trend toward a less atherogenic lipid profile was observed in the upper tertile. In conclusion, the intake of moderate amounts of phytosterols naturally present in habitual diet may affect cholesterol metabolism and specially the rate of cholesterol synthesis as estimated by the surrogate marker lathosterol-to-cholesterol ratio in serum (AU)

Role of naturally-occurring plant sterols on intestinal cholesterol absorption and plasmatic levels.

Cardiovascular disease is a major health problem in developed countries although its incidence is relatively lower in Mediterranean countries which is partly ascribed to dietary habits. Epidemiologic evidence shows that elevated serum cholesterol, specifically low-density lipoprotein cholesterol (c-LDL), increases cardiovascular disease. Phytosterols are bioactive compounds, found in all vegetable foods, which inhibit intestinal cholesterol absorption and, therefore, have a serum cholesterol-lowering effect. Intestinal cholesterol absorption is a multistep process where plant sterols and stanols may act: a) attenuating the NPC1L1 gene expression, which may result in a lower cholesterol uptake from the lumen; b) lowering the cholesterol esterification rate by the ACAT2 (acyl-CoA cholesterol acyltransferase) and, consequently, the amount of cholesterol secreted via the chylomicrons and c) upregulating the expression of ABC-transporters ABCG5 and ABCG8 in intestinal cells, which may result in an increased excretion of cholesterol by the enterocyte back into the lumen. Many clinical trials proved that commercial products enriched with phytosterols reduce cholesterol levels. Likewise, recent studies show that phytosterols present in natural food matrices are also effective and could be an important component of cardioprotective dietary patterns such as the Mediterranean diet.

Papel de los esteroles vegetales de la dieta sobre la absorción intestinal de colesterol y sus niveles plasmáticos / Role of naturally-occurring plant sterols on intestinal cholesterol absorption and plasmatic levels

Cardiovascular disease is a major health problem in developed countries althoughits incidence is relatively lower in Mediterranean countries which is partly ascribedto dietary habits. Epidemiologic evidence shows that elevated serum cholesterol,specifically low-density lipoprotein cholesterol (c-LDL), increases cardiovasculardisease. Phytosterols are bioactive compounds, found in all vegetable foods, whichinhibit intestinal cholesterol absorption and, therefore, have a serum cholesterolloweringeffect. Intestinal cholesterol absorption is a multistep process where plantsterols and stanols may act: a) attenuating the NPC1L1 gene expression, which mayresult in a lower cholesterol uptake from the lumen; b) lowering the cholesterol esterificationrate by the ACAT2 (acyl-CoA cholesterol acyltransferase) and, consequently,the amount of cholesterol secreted via the chylomicrons and c) upregulatingthe expression of ABC-transporters ABCG5 and ABCG8 in intestinal cells, whichmay result in an increased excretion of cholesterol by the enterocyte back into thelumen. Many clinical trials proved that commercial products enriched with phytosterolsreduce cholesterol levels. Likewise, recent studies show that phytosterols presentin natural food matrices are also effective and could be an important componentof cardioprotective dietary patterns such as the Mediterranean diet(AU)

La enfermedad cardiovascular es un problemade salud importante en los países desarrollados,aunque su incidencia es relativamentemenor en los países mediterráneos lo que esparcialmente atribuible a los hábitos dietéticos.Existen evidencias epidemiológicas que muestranque el colesterol sérico elevado, específicamenteel colesterol ligado a las lipoproteínas debaja densidad (c-LDL), incrementa la enfermedadcardiovascular. Los fitosteroles son compuestosbioactivos, presentes en todos los alimentosde origen vegetal, que inhiben la absorciónintestinal de colesterol y, por lo tanto, tienenun efecto reductor en el colesterol sérico.La absorción intestinal de colesterol es un procesomulti-etapa donde los esteroles y estanolesvegetales pueden actuar de diversas formas:a) atenuando la expresión del gen NPC1L1, loque puede suponer una disminución del ingresode colesterol desde el lumen intestinal; b)disminuyendo la tasa de esterificación delcolesterol por la ACAT2 (acil-CoA colesterolaciltransferasa) y, en consecuencia, la cantidadde colesterol excretada vía quilomicrones y c)aumentando la expresión de los ABC-transportadoresABCG5 y ABCG8 en las célulasintestinales, lo que puede derivar en una excreción incrementada de colesterol desde el enterocitohacia el lumen. Diversos ensayos clínicoshan demostrado que los productos comercialesenriquecidos con fitosteroles reducen losniveles de colesterol. Sin embargo, estudiosrecientes muestran que los fitosteroles presentesen matrices alimentarias naturales tambiénpueden ser bioactivos y podrían ser un componenteimportante de los patrones dietéticoscardioprotectores como es la dieta Mediterránea(AU)

A moderate intake of phytosterols from habitual diet affects cholesterol metabolism.

Cholesterol metabolism homeostasis is the result of a balance between synthesis, degradation and intestinal absorption. It is well established that intestinal cholesterol absorption efficiency can be modified by the intake of phytosterol-enriched food and, therefore, have a serum cholesterol-lowering effect. Recent epidemiological and clinical studies have shown that presence of phytosterols at normal diet levels could also be effective on lowering total and LDL serum cholesterol since they affect whole-body cholesterol metabolism even at those moderate doses. The aim of this study was to analyze the effect of the levels of the naturally-occurring phytosterols in the diet on cholesterol metabolism parameters. In order to do that a group of 99 healthy volunteers was studied for their dietary habits and surrogate markers of cholesterol synthesis and absorption. The mean daily dietary intake of phytosterols, measured by a food semiquantitative frequency questionnaire, was found to be 494 mg being beta-sitosterol the major contributor to it. Subjects were classified into tertiles according to their total phytosterol intake and comparisons were done between subgroups. No statistical differences were observed for surrogate markers of intestinal cholesterol absorption, but a significant increase in the cholesterol synthesis surrogate marker lathosterol-to-cholesterol ratio associated to highest dietary phytosterol intake was observed. Regardless of this, only a non significant trend toward a less atherogenic lipid profile was observed in the upper tertile. In conclusion, the intake of moderate amounts of phytosterols naturally present in habitual diet may affect cholesterol metabolism and specially the rate of cholesterol synthesis as estimated by the surrogate marker lathosterol-to-cholesterol ratio in serum.

Alcoholic beverage preference and dietary pattern in Spanish university graduates: the SUN cohort study.

OBJECTIVE: To describe the association between alcohol beverage preference and dietary habits comparing wine drinkers with other alcoholic beverage drinkers and with nondrinkers in Spanish university graduates. SUBJECTS: A total of 10 526 men and women, who were recruited using mailed questionnaires, participated in this study. METHODS: A semiquantitative food frequency questionnaire previously validated in Spain was used together with other questionnaires designed to collect lifestyle characteristics. RESULTS: Wine drinkers reported higher intake of fibre and olive oil, and lower consumption of fat (only men), dairy products, sugared soda drinks and fast food as compared with other alcoholic beverage groups and nondrinkers. Men nondrinkers were more likely to be physically active during their leisure time than wine drinkers. No relevant differences were found in adherence to the Mediterranean food pattern according to alcoholic beverage preference. CONCLUSION: This similarity in dietary patterns between wine drinkers and other groups suggests that the positive cardiovascular effects reported for wine should not be attributed to an overall healthier dietary pattern of wine drinkers. .

[Nutrition and dietary recommendations for the elderly "Public Health" Working Group of the Spanish Nutrition Society]. / Nutrición y recomendaciones dietéticas para personas mayores. Grupo de trabajo "Salud pública" de la Sociedad Española de Nutrición (SEN).

With the increase of life expectancy, the desire to maintain good health, functionality and maximum quality of life at advanced ages, for which nutrition plays a critical role, is a priority for the elderly. Though genetic factors are a determinant of life expectancy, there are several extrinsic factors which have a great influence on the quality of life of the elderly. Diet and nutritional status have a great influence, especially in the prevention and treatment of several diseases, which affect this heterogeneous and vulnerable age group. The nutritional status and needs of elderly people are associated with age-related biological, psychological and often socio-economic changes. All of these changes can increase the risk of developing a number of age-related diseases. In developed countries the elderly are the most affected by malnutrition, either because of a deficiency (energy and several nutrients) or an excess, leading to obesity and related diseases. This review highlights the most important factors affecting nutritional status in elderly people and focus on the need to maintain adequate physical activity level and an optimal physic, psychic and social functional capacity. It discusses dietary reference intakes and guidelines to improve and/or maintain adequate nutritional status in older people in order to reduce susceptibility to some illness and disease.

Nutrición y recomendaciones dietéticas para personas mayores. Grupo de trabajo "Salud pública" de la Sociedad Española de Nutrición (SEN) / Nutrition and dietary recommendations for the elderly "public health" working group of the spanish nutrition society

Con el incremento de la esperanza de vida, el deseo de mantener una buena salud, funcionalidad y una máxima calidad de vida en edades avanzadas constituye una prioridad en las personas mayores. Aunque la genética es un determinante de esta expectativa de vida, existen otros factores extrínsecos directamente implicados en la calidad de vida del anciano, entre los que cabe destacar la alimentación. La dieta y el estado nutricional tienen gran influencia, particularmente en la prevención o tratamiento de diversas enfermedades que afectan a este grupo, uno de los más heterogéneos y vulnerables de la población de los países desarrollados con un mayor riesgo de sufrir desequilibrios, carencias y problemas nutricionales. Esto es debido, por un lado, a que las necesidades de algunos nutrientes pueden ser mayores que en etapas anteriores y, por otro, a su menor capacidad para regular todos los procesos relacionados con la ingesta de alimentos como consecuencia del progresivo deterioro de casi todas las funciones biológicas. Los numerosos cambios físicos, psíquicos y sociales que acompañan al envejecimiento y la mayor prevalencia de enfermedades crónicas, también contribuyen a esta situación. Diversos estudios han puesto de manifiesto el riesgo de ingestas inadecuadas y de malnutrición proteico-energética, aumentando la vulnerabilidad a otras enfermedades. En este trabajo se hace una revisión de los principales condicionantes del estado nutricional en el anciano, de la importancia de la capacidad funcional física, psíquica y social y de la actividad física y de su repercusión en el estado nutricional. Se describen las ingestas de referencia y las recomendaciones dietéticas más actuales, tratando de establecer las condiciones dietéticas y de estilo de vida que pueden contribuir a preservar las funciones corporales y minimizar las enfermedades crónicas en las personas de edad (AU)

With the increase of life expectancy, the desire to maintain good health, functionality and maximum quality of life at advanced ages, for which nutrition plays a critical role, is a priority for the elderly. Though genetic factors are a determinant of life expectancy, there are several extrinsic factors which have a great influence on the quality of life of the elderly. Diet and nutritional status have a great influence, especially in the prevention and treatment of several diseases, which affect this heterogeneous and vulnerable age group. The nutritional status and needs of elderly people are associated with age-related biological, psychological and often socio-economic changes. All of these changes can increase the risk of developing a number of age-related diseases. In developed countries the elderly are the most affected by malnutrition, either because of a deficiency (energy and several nutrients) or an excess, leading to obesity and related diseases. This review highlights the most important factors affecting nutritional status in elderly people and focus on the need to maintain adequate physical activity level and an optimal physic, psychic and social functional capacity. It discusses dietary reference intakes and guidelines to improve and/or maintain adequate nutritional status in older people in order to reduce susceptibility to some illness and disease (AU)

Dietas adelgazantes / Slimming diets

La intervención dietética tiene como objetivos: alcanzar un balance energético negativo, conseguir un peso saludable en la persona obesa y lograr la instauración de hábitos alimentarios saludables para mantener el peso perdido a largo plazo. Considerando el tratamiento dietético de la obesidad un proceso que se mantiene por largos periodos de tiempo, la intervención dietética deberá ser realizada en función de las características fisiopatológicas y psicosociales de la persona obesa. Además, la terapia dietética deberá ser equilibrada, saludable y adaptada a las preferencias alimentarias del paciente. A lo largo de los años, debido a la necesidad y búsqueda de una pérdida de peso rápida, se han originado, creado e inventado dietas mágicas que se han hecho populares y que carecen de eficacia comprobada y rigor científico. Este trabajo, hace referencia a la dieta hipocalórica equilibrada y revisa las dietas adelgazantes más conocidas y llevadas a cabo por la población obesa y/o con sobrepeso. (AU)

Causas de obesidad / Causes of obesity

La etiología y tratamiento de la obesidad exige el conocimiento de los mecanismos que controlan la homeostasis de los sustratos combustibles y la adiposidad. Los procesos de regulación ajustan el aporte de sustratos combustibles y las demandas de energía con objeto de mantener una masa corporal estable. A la luz de las más recientes investigaciones se puede hipotetizar que el control del peso corporal y la composición depende de un eje integrado por tres componentes autorregulados: apetito, metabolismo, termogénesis y depósitos grasos. Los factores más importantes implicados en la obesidad parecen ser los hábitos dietéticos y de actividad física, que están afectados por genes, que a su vez, afectan al gasto energético, al metabolismo de sustratos energéticos y al consumo de alimentos. Sin embargo, las crecientes tasas de obesidad no pueden ser explicadas exclusivamente por causas genéticas, ya que en algunos casos están asociados al consumo de dietas de alta densidad energética o ricas en grasa, y por el creciente sedentarismo de las sociedades, tanto en países desarrollados como en vías de desarrollo. El estudio de la genética y el estilo de vida implicados en la ganancia de peso corporal y la obesidad pueden facilitar la puesta en marcha de acciones de prevención (AU)

Sistema nervioso y obesidad / Nervous system and obesity

A pesar de las grandes variaciones diarias en la ingesta de nutrientes, las reservas de energía del organismo permanecen constantes en el tiempo, lo que sugiere la existencia de numerosos mecanismos reguladores de la adiposidad, el gasto energético y el apetito. La distensión gástrica, la absorción intestinal de nutrientes, las reservas lipídicas y de glucógeno, la tasa de utilización de substratos energéticos a escala central y periférica, la palatabilidad del alimento y otros factores psicológicos influyen en la regulación a corto plazo de la oxidación y el almacenamiento de macronutrientes, así como del apetito. Además, hormonas como la insulina y la leptina actúan más a largo plazo a nivel del cerebro, reduciendo la ingesta y aumentando el gasto energético. En dicho órgano, regulan importantes circuitos neuronales, sobre todo a nivel hipotalámico, que inician señales efectoras que controlan la homeostasis energética. Este trabajo estudia el papel del sistema nervioso central en la regulación del apetito y del balance energético. (AU)

[Causes of obesity]. / Causas de obesidad.

The aetiology and treatment of obesity requires a knowledge of the mechanisms that control the homeostasis of the fuel substrates and adiposity. The processes of regulation adjust the supply of macronutrients and energy demands with the aim of maintaining a stable body mass. In the light of the most recent research, the hypothesis can be advanced that the control of body weight and its composition depends on an axis integrated by three self-regulated components: appetite, stores thermogenesis and fat deposits. The most important factors involved in obesity seem to be dietary habits diet and physical activity, which are affected by genes, which in their turn affect energy expenditure, the metabolism of energy substrates and food consumption. However, the growing rates of obesity cannot be explained exclusively by genetic causes, since they are in some cases associated with the consumption of diets with a high energy density or rich in fat, and by a growing sedentary life style in society, both in developed and developing countries. The study of genetics and life style involved in the increase of body weight and obesity can facilitate the implementation of preventive actions.

[Nervous system and obesity]. / Sistema nervioso y obesidad.

In spite of the great daily variations in the ingestion of nutrients, the energy reserves of the body remain constant over time, which suggests the existence of numerous mechanisms regulating adiposity, energy expenditure and appetite. Gastric distention, the intestinal absorption of nutrients, lipid and glycogen reserves, the rate of utilisation of energy substrates on a central and peripheral scale, the palatability of the food and other psychological factors, influence the short term regulation of oxidation and the storage of macronutrients, as well as appetite. Besides, hormones such as insulin and leptin act over the longer term on the brain, reducing ingestion and increasing energy expenditure. Important neuronal circuits regulate this organ, above all at the hypothalamic level, which initiate effector signals that control energy homeostasis. This paper studies the role of the central nervous system in the regulation of appetite and energy balance

[Slimming diets]. / Dietas adelgazantes.

Dietetic intervention has the following aims: to achieve a negative energy balance, obtain a healthy weight in the obese person and achieve the installation of healthy eating habits in order to maintain weight loss in the long term. Considering dietetic treatment of obesity as a process that is maintained for long periods of time, dietetic intervention should be carried out depending on the physio-pathological and psycho-social characteristics of the obese person. Besides, dietetic therapy should be balanced, healthy and adapted to the eating preferences of the patient. Over the years, due to need and the quest for rapid weight loss, magic diets have been occasioned, created and invented that have become popular and that lack proven efficacy and scientific rigour. This paper makes reference to a balanced hypocaloric diet and reviews the slimming diets that are best known and most used by the obese and/or overweight population.

Postprandial de novo lipogenesis and metabolic changes induced by a high-carbohydrate, low-fat meal in lean and overweight men.

BACKGROUND: Adjustments of carbohydrate intake and oxidation occur in both normal-weight and overweight individuals. Nevertheless, the contribution of carbohydrates to the accumulation of fat through either reduction of fat oxidation or stimulation of fat synthesis in obesity remains poorly investigated. OBJECTIVE: The objective of this study was to assess the postprandial metabolic changes and the fractional hepatic de novo lipogenesis (DNL) induced by a high-carbohydrate, low-fat meal in lean and overweight young men. DESIGN: A high-carbohydrate, low-fat meal was administered to 6 lean and 7 overweight men after a 17.5-h fast. During the fasting and postprandial periods, energy expenditure (EE), macronutrient oxidation, diet-induced thermogenesis, and serum insulin, glucose, triacylglycerol, and fatty acids were measured. To determine DNL, [1-13C]sodium acetate was infused and the mass isotopomer distribution analysis method was applied. RESULTS: After intake of the high-carbohydrate meal, the overweight men had hyperinsulinemia and higher fatty acid and triacylglycerol concentrations than did the lean men. The overweight group showed a greater EE, whereas there was no significant difference in carbohydrate oxidation between the groups. Nevertheless, the overweight men had a marginally higher protein oxidation and a lower lipid oxidation than did the lean men. DNL was significantly higher before and after meal intake in the overweight men and was positively associated with fasting serum glucose and insulin concentrations. Furthermore, postprandial DNL was positively correlated with body fat mass, EE, and triacylglycerol. CONCLUSION: After a high-carbohydrate, low-fat meal, overweight men had a lower fat oxidation and a higher fractional hepatic fat synthesis than did lean men.

[Effects of a dietary intervention on the nutritional status of hemodialyzed patients: differences between men and women]. / Efectos de una intervención dietética sobre el estado nutricional de pacientes en hemodiálisis: diferencias entre varones y mujeres.

The growing interest in the nutritional status of dialyzed patients arises from the fact that it plays an important role in the evolution, morbidity and mortality of renal patients. In the current study the effects have been assessed of a dietary intervention lasting 6 months, based on a food exchange list, on the nutritional status of a group of 49 hemodialysis patients as well as the different effects between men and women. The initial and final evaluation of the nutritional status was performed by estimating energy and nutrient intake with a 24 hour recall, determination of body composition by anthropometry, bioelectrical impedance and infrared interactance and biochemical measurements related to the nutritional status of the patients undergoing hemodialysis. At the end of the study, a significant increase was seen in the energy and macronutrient intake, which was more prominent in females. The body composition analysis showed a favourable evolution as compared to other studies; which was better in women who maintained the muscle mass stable and increased fat mass. The biochemical profile showed an increase of the C3 complement, while other markers such as amino acid profile and IGF I remained unchanged at the end of the study, being both similar in males and females. The dietary intervention was found to be useful in the prevention of the progression of malnutrition in these patients, apparently with a more beneficial effect on females.