Importancia de la leche en la nutrición del adulto mayor / Importance of milk in elderly nutrition

El proceso de envejecimiento es un fenómeno complejo que abarca cambios moleculares, celulares, fisiológicos y psicológicos. Los adultos mayores son especialmente susceptibles a presentar problemas nutricionales, tanto por alteraciones gastrointestinales, como por cambios en los requerimientos de nutrientes, alteraciones en la sensación del gusto, deterioro en la dentición, uso de medicamentos, depresión, aislamiento social y pobreza, siendo esta última la más importante causa de malnutrición en este grupo etáreo. En la mayor parte de la población el consumo de alimentos saludables se encuentra muy limitado, no alcanzando a cubrir los requerimientos de proteínas, minerales y micronutrientes. Una alimentación saludable, variada, con buen aporte proteico y de micronutrientes, manteniendo una adecuada actividad física es fundamental para tener una mejor calidad de vida. Dentro de una alimentación saludable, la leche cumple un papel fundamental por su aporte de proteínas y nutrientes esenciales, dentro de los cuales se destacan las vitaminas B1, B2 y minerales como calcio y fósforo

Diferencias en la oxidación de substratos energéticos entre mujeres obesas y normopeso / Differences in energy substrate oxidation between obese and normal weight women

Se compara la oxidación de lípidos y de CHO en mujeres controles y obesas, en condiciones de ayuno y luego de un desayuno de prueba conteniendo ácidos grasos enriquecidos con 13C. Dieciséis mujeres de 40-55 años, saludables, con peso estable en los tres meses previos y durante el estudio fueron agrupadas según índice de masa corporal (IMC): 8 obesas) y 8 normopeso (IMC 30-40 y 20-25 respectivamente). El metabolismo oxidativo se estudió en tres oportunidades en cada sujeto bajo condiciones de reposo: 1) bajo condiciones post absortivas (TMR), 2) luego de un desayuno (aporte energético equivalente al 40 por ciento del TMR) con adición de 13C-ácido octanoico y 3) idem, pero con adición de 13C-ácido palmítico en reemplazo del ác. octanoico. El gasto energético y la oxidación total de sustratos se evaluó con calorimetría indirecta (CAL). La oxidación de los sustratos marcados, se evaluó por espectrometría de masas y CAL. Bajo condiciones de ayuno, ambos grupos utilizaron como principal combustible metabólico a las grasas (66,38 ñ 35,08 por ciento las obesas y 56,83 ñ 28,18 por ciento las normopeso). Bajo condiciones de alimentación, las obesas oxidaron mayor cantidad de lípidos (55,23 ñ 20,44 por ciento vs 40,84 ñ 17,39 por ciento en controles), tanto en forma total como ajustado por la cantidad de grasa ingerida, peso y composición corporal (p<0,05). La oxidación de lípidos estuvo en directa asociación con la masa grasa de los sujetos (r=0,66). Luego de 3 horas, la oxidación de ácido 13C-octanoico, fue similar en ambos grupos (21,3 ñ 10,4 en obesas y 26,5 ñ 9,0 por ciento en controles). La oxidación de 13C-palmítico fue muy baja en ambos grupos, aunque significativamente menor en las obesas (0,5 por ciento ñ 0,2 por ciento vs 0,9 por ciento ñ 0,4 por ciento). La mayor oxidación de lípidos según CAL, en obesos de peso estable, puede responder a un mecanismo destinado a prevenir nuevas ganancias de peso o pudiera representar una complicación metabólica del exceso de peso

Importancia del ácido fólico en la medicina actual / The importance of folic acid in present medicine

Lately, folic acid deficiency is gaining a predominant role in the pathogenesis of congenital malformations and cardiovascular diseases in adults. The planning of individual and population preventive strategies for these diseases must consider this deficiency. This paper reviews the anatomical, biochemical and molecular bases of neural tube defects and cardiovascular diseases in adults. In these two frequent diseases, folic acid supplementation has shown a clear cut protective effect

Nuevas piezas del puzzle de la aterogénesis / New pieces in the puzzle of atherogenesis

The contribution of high serum levels of cholesterol to atherogenesis has been widely recognized, but the mechanisms are not completely clear. Numerous publications have emphasized that oxidized, but not native low-density lipoproteins, are the particles incorporated into the arterial wall. A group of receptors generically called scavenger (SR), actively bind these modified lipoproteins and incorporate them into monocytes-macrophages, in the arterial intima. SR are not down regulated by intracellular concentrations of cholesterol, thus accumulating huge amounts of lipids, transforming monocyte-macrophages into foam cells, predominant cell type of the fatty streak. The simultaneous cytokine production and migration of other cellular types progressively transform this initial lesion into the organized atherosclerotic plaque. In this setting SR, which are up-regulated by oxidized LDL, play a central promoting role. Its presence has been demonstrated in arterial plaques both in human and animal models, and its blockade protects animals from development or progression of atherosclerosis. In humans, elevated antibody titers to oxidized LDL in patients with coronary stenosis, and increased SR activity, in pro-atherogenic conditions such as haemodyalisis, indicate that this model may operate as well, but the evidences are still not solid enough to definitively conclude that the oxidized-LDL-SR hypothesis is a finished puzzle

Estado nutritivo y gasto energético en ancianos de distinto nivel socioeconómico / Nutritional status and energy expenditure in elders of differing socioeconomic level

Background: Income and socioeconomic status can influence nutritional status of individuals. Since elders are a more vulnerable group to nutritional deficiencies, socioeconomic status could have a special relevance on nutrition of elderly people. Aim: To assess the influence of socioeconomic status on the nutritional status of elders. Material and methods: Elders of both sexes of high socioeconomic level and age and sex matched elders of low socioeconomic status were studied. Anthropometry, body composition using double beam X ray absorptiometry, resting energy expenditure using an open circuit indirect calorimeter, routine biochemistry, blood levels of folic acid, vitamin B12 and homocysteine were measured in all subjects. Results: Fourteen female elders of high socioeconomic level, 14 females of low level and 12 males of each level were studied. Mean age of females and males was 71.5 ñ 3.7 and 73.9 ñ 4.2 years old respectively. Males and females of high socioeconomic status were taller than their counterparts of low status. Females of high socioeconomic status had a lower body mass index than their pairs of low status (26.3 ñ 3.8 and 30.2 ñ 5.6 kg/m2 respectively p <0.02). Men of high economic status had a higher fat mass than their pairs of low level (20.3 ñ 3.5 and 15.1 ñ 5.5 kg respectively, p <0.005). No differences in resting energy expenditure in women of differing socioeconomic level were observed. Men of high level had a higher energy expenditure than their counterparts of low level (36.0 ñ 4.9 and 32.8 ñ 2.2 Kcal/kg lean body mass/day respectively, p<0.02). Low level male elders had higher serum total cholesterol and triglycerides. Folic acid, vitamin B12 and homocysteine levels were within normal limits. Dietary intake showed deficiencies in calorie, protein and vitamin intake in all subjects. Conclusions: In this group of elders, low socioeconomic level did not produce a significant impact on nutritional status

Niveles de homocisteína en adultos sanos chilenos / Serum homocysteine levels in healthy chilean adults

Background: Hyperhomocysteinemia is a newly recognized cardiovascular risk factor that is present in 10 to 20percent of European and North American individuals. Aim: To measure homocysteine levels in healthy adults in Chile. Subjects and methods: Serum homocysteine levels were measured in healthy adults using a fluorimetric HPLC method. Folic acid, vitamin B12, serum lipids, creatinine and glucose were also assessed. All subjects answered a dietary habits questionnaire. Results: One hundred twenty eight subjects (90 female) aged 22 to 78 years old were studied. Homocysteine levels were 9.7 ñ 6.0 and 7.0 ñ 3.1 µmol/l in men and women respectively (p< 0.001). Folic acid levels were 6.1 ñ 2.7 and 6.1 ñ 2.9 ng/ml in men and women, and 24percent of individuals had values below 4 ng/ml. Vitamin B12 levels were 393 ñ 147 and 393 ñ 163 pg/ml in the same groups. There was a negative correlation between homocysteine and folic acid levels and a positive correlation between homocysteine and creatinine levels. Conclusions: Homocysteine levels in healthy Chilean individuals are similar to those reported abroad. Low folic acid levels were found in 24percent of subjects

Permeabilidad intestinal en alcohólicos sin daño hepático / Intestinal permeability in alcoholics without hepatic damage

Methods: Thirty seven male subjects were studied, 18 controls and 19 alcoholic: All subjects underwent an anthropometric assessment and dietary history. Lactulose/mannitol test was performed during the third day of abstinence in alcoholics. After an 8 hour overnight fast, subjects drank 200 ml of a solution containing 56 g lactulose and 5 g mannitol. Subsequently, urine was collected during the following 5 hours, where both sugars were measured by gas chromatography. Results: Median values of lactulose/mannitol ratio were similar in alcoholics and controls (0.011, range 0.005-0.071 vs 0.014, range 0.005-0.027 respectively). However, absolute urinary excretion of both lactulose and mannitol was lower in alcholics. There was no relationship betwwen nutritional status and urinary excretion of lactulose, mannitol or lactulose/mannitol ratio. Conslusion: In this alcoholic patients, no changes were observed in intestinal permability

Resultados de 2 años de un programa de rehabilitación de enfermos alcohólicos / Results of a long term alcoholism rehabilitation program

One hundred eighty two alcoholics admitted for treatment of their alcoholism were followed during 2 years in a special clinic. The effects of length of alcoholism, withdrawal symptoms on admission and the presence of histological liver damage on long term outcome were assessed using life table analysis. During the 2 years period, 75 percent of patients were lost from control and 63 percent relapsed in their alcoholic ingestion. None of the above mentionated parameters had an effect on relapse or loss from follow up. There are high attrition and failure rates and the length of alcoholism, degree of initial withdrawal and the liver damage do not influence the long term results of this program

Marcadores de fibrogénesis hepática en pacientes alcohólicos / Hepatic fibrogenesis markers in alcoholic patients

Serum P-III-P and laminim levels were measured in asymptomatic alcoholics during detoxication treatment. Liver biopsies were obtained, in order to detect liver damage, which was graded with a numeric score, considering values over 6 as severe damage. Serum fibrogenesis markers were also measured in a group of decompensated alcoholic cirrhotics. P-III-P levels were significantly higher in cirrhotic patients compared to alcoholics with or without liver damage and to normal controls. Laminin was not different between groups. P-III-P did not correlate with histological score in asymptomatic patients. In this study P-III-P and P1 laminin were not usefull discriminators of severe liver damage among asymptomatic alcoholics; their levels were found to rises significantly only when liver disease has become clinically evident

Métodos de estimación de la composición corporal de ancianos: análisis crítico / Body composition estimation methods in elderly: critical analysis

The objective of this study was to compare the values obtained for total body fat obtained with deuterium dilution, anthropometry and bioimpedance in 41 institutionalized elderly individuals (65-90 years old). The values obtained with each technique were compared using the graphic analysis proposed by Bland and Altman, that plots the difference between measurements with both methods against their average. In men (n=20) and women (n=21), the best degree of agreements was obtained between the values measured by deuterium dilution and those calculated from skinfolds (mean difference=1.4 percent and 6.9 percent respectively). The limits of agreement (ñ2SD) for skinfolds reached a maximun of 14.8 percent in men, and 16.8 percent in women. These values tend to underestimate fat in the obese and overestimate it in thinner subjects. For bioimpedance and deuterium dilution, the inter-method difference is significantly greater: 9.3 percent in men and 14.7 percent in women. This lack of agreement is attributed to the fact that the bioimpedance equipment utilizes equations validated for younger adults. In conclusion, estimation of body composition using skinfolds has the smallest difference compared with deuterium dilution, eventhougt individual measurements are not clinically acceptable. Caution is recommended when using individual measurements of body composition in the elderly, due to large errors in the determinations

El sistema mayor de histocompatibilidad como factor de riesgo de la enfermedad hepática alcohólica / Major histocompatibility system as a risk factor of alcoholic hepatic disease

Several associations between alleles of the major histocompatibility system and alcoholic liver disease have been described. However, these are weak and changes from one population to another. The aim of this work was to search for a possible genetic risk factor for alcoholic liver disease among chilean alcoholics. We studied blood groups, serum proteins and HLA antigens in 39 alcoholic cirrhotics, 104 asymptomatic alcoholics and 44 non alcoholic controls. Asymptomatic alcoholics were also subjected to a percutaneous liver biopsy that showed moderate to severe histological liver damage in 46 subjects (44 percent). No differences in the studied genetic markers, were found among the four groups. It is concluded that this study does not confirm previously reported associations between genetic markers and alcoholic liver disease