[Palm oil and cardiovascular health: considerations to evaluate the literature critically]. / Aceite de palma y salud cardiovascular: consideraciones para valorar la literatura.

Palm oil is obtained from Elaeis guineensis, E. oleifera or the hybrid OxG palm fruits. When crude, it contains high carotenoid concentrations (responsible for the red color), tocopherols and tocotrienols, but most of them are eliminated during its refining. Palm oil main components are palmitic and oleic acids, both near 50%, but their proportion changes depending on the fraction used. Fatty acids absorption and the effect on blood lipid profile depend on the position in the triacylglycerol, especially in the sn-2 position. The location of the monounsaturated or saturated fatty acids varies depending on the type of palm oil or fraction used. We critically review the two main reviews published about palm oil, which analyze 67 publications, and several studies that are more recent. Most of the studies were performed in non-European countries where palm oil is the main culinary oil. The effect on cardiovascular risk factors depends on the fat used as counterpart. Palm oil improves lipid profile after a diet rich in trans and saturated fats, while it impairs lipid profile after a diet rich in monounsaturated and polyunsaturated fats. Relevant methodological errors have been identified, such as not differentiating between palm oil, palm kernel oil and their fractions, comparing single fatty acids with whole oils or fats, or not considering physical activity or other factors that can affect blood lipids. No studies considering palm oil as an ingredient in a Mediterranean diet context, where olive oil is the main culinary oil, were found, so extrapolation of data is currently very difficult.

El aceite de palma se obtiene de los frutos de Elaeis guineensis, E. oleifera y el cruce de ambas, OxG (híbrida). En crudo contiene gran proporción de carotenoides (responsables del color rojo), tocoferoles y tocotrienoles, pero se pierden durante su refinado. En su composición destacan los ácidos grasos palmítico y oleico, casi al 50%, aunque su proporción varía según la fracción en la que se utilizan. La absorción de los ácidos grasos y, por tanto, su efecto sobre el perfil lipídico plasmático dependen de su posición en el triglicérido, especialmente en sn-2. Según el aceite de palma o la fracción, variará dicha posición de los ácidos grasos monoinsaturados o saturados. Se revisan críticamente las dos principales revisiones publicadas en relación al aceite de palma, que incluyen un total de 67 artículos, además de otros estudios más recientes. La mayoría se realizan en países no europeos donde el aceite de palma es el principal aceite culinario. Su efecto sobre el perfil cardiovascular varía según con qué se compare, mejorándolo frente a las grasas trans y saturadas y empeorándolo frente a las grasas mono y poliinsaturadas. Hemosdetectado errores metodológicos importantes, como no diferenciar entre palma, palmiste o fracciones, comparar ácidos grasos con aceites o no considerar la actividad física y otros factores que influyen sobre el perfil lipídico. No hemos encontrado estudios realizados con aceite de palma como ingrediente de alimentos en un contexto de dieta mediterránea, donde el principal aceite culinario es el de oliva, que serían los extrapolables a nuestro entorno.

Aceite de palma y salud cardiovascular: consideraciones para valorar la literatura / Palm oil and cardiovascular health: considerations to evaluate the literature critically

El aceite de palma se obtiene de los frutos de Elaeis guineensis, E. oleifera y el cruce de ambas, OxG (híbrida). En crudo contiene gran proporción de carotenoides (responsables del color rojo), tocoferoles y tocotrienoles, pero se pierden durante su refinado. En su composición destacan los ácidos grasos palmítico y oleico, casi al 50%, aunque su proporción varía según la fracción en la que se utilizan. La absorción de los ácidos grasos y, por tanto, su efecto sobre el perfil lipídico plasmático dependen de su posición en el triglicérido, especialmente en sn-2. Según el aceite de palma o la fracción, variará dicha posición de los ácidos grasos monoinsaturados o saturados. Se revisan críticamente las dos principales revisiones publicadas en relación al aceite de palma, que incluyen un total de 67 artículos, además de otros estudios más recientes. La mayoría se realizan en países no europeos donde el aceite de palma es el principal aceite culinario. Su efecto sobre el perfil cardiovascular varía según con qué se compare, mejorándolo frente a las grasas trans y saturadas y empeorándolo frente a las grasas mono y poliinsaturadas. Hemosdetectado errores metodológicos importantes, como no diferenciar entre palma, palmiste o fracciones, comparar ácidos grasos con aceites o no considerar la actividad física y otros factores que influyen sobre el perfil lipídico. No hemos encontrado estudios realizados con aceite de palma como ingrediente de alimentos en un contexto de dieta mediterránea, donde el principal aceite culinario es el de oliva, que serían los extrapolables a nuestro entorno

Palm oil is obtained from Elaeis guineensis, E. oleifera or the hybrid OxG palm fruits. When crude, it contains high carotenoid concentrations (responsible for the red color), tocopherols and tocotrienols, but most of them are eliminated during its refining. Palm oil main components are palmitic and oleic acids, both near 50%, but their proportion changes depending on the fraction used. Fatty acids absorption and the effect on blood lipid profile depend on the position in the triacylglycerol, especially in the sn-2 position. The location of the monounsaturated or saturated fatty acids varies depending on the type of palm oil or fraction used. We critically review the two main reviews published about palm oil, which analyze 67 publications, and several studies that are more recent. Most of the studies were performed in non-European countries where palm oil is the main culinary oil. The effect on cardiovascular risk factors depends on the fat used as counterpart. Palm oil improves lipid profile after a diet rich in trans and saturated fats, while it impairs lipid profile after a diet rich in monounsaturated and polyunsaturated fats. Relevant methodological errors have been identified, such as not differentiating between palm oil, palm kernel oil and their fractions, comparing single fatty acids with whole oils or fats, or not considering physical activity or other factors that can affect blood lipids. No studies considering palm oil as an ingredient in a Mediterranean diet context, where olive oil is the main culinary oil, were found, so extrapolation of data is currently very difficult

A single day of bed rest, irrespective of energy balance, does not affect skeletal muscle gene expression or insulin sensitivity.

NEW FINDINGS: What is the central question of this study? What are the initial metabolic and molecular events that underpin bed rest-induced skeletal muscle deconditioning, and what is the contribution of energy balance? What is the main finding and its importance? A single day of bed rest, irrespective of energy balance, did not lead to overt changes in skeletal muscle gene expression or insulin sensitivity. More than 1 day of physical inactivity is required to observe the insulin resistance and robust skeletal muscle transcriptional responses associated with bed rest and consequent alterations in energy balance. ABSTRACT: The initial metabolic and molecular events that underpin disuse-induced skeletal muscle deconditioning, and the contribution of energy balance, remain to be investigated. Ten young, healthy men (age 25 ± 1 years; body mass index 25.3 ± 0.8 kg·m-2 ) underwent three 24 h laboratory-based experimental periods in a randomized, crossover manner: (i) controlled habitual physical activity with an energy-balanced diet (CON); (ii) strict bed rest with a diet to maintain energy balance (BR-B); and (iii) strict bed rest with a diet identical to CON, consequently resulting in positive energy balance. Continuous glucose monitoring was performed throughout each visit, with vastus lateralis muscle biopsies and an oral glucose tolerance test performed before and after. In parallel with muscle samples collected from a previous 7 day bed rest study, biopsies were used to examine the expression of genes associated with the regulation of muscle mass and insulin sensitivity. A single day of bed rest, irrespective of energy balance, did not lead to overt changes in whole-body substrate oxidation, indices of insulin sensitivity [i.e. homeostatic model assessment of insulin resistance, BR-B from 2.7 ± 1.7 to 3.1 ± 1.5 (P > 0.05) and Matsuda index, BR-B from 5.9 ± 3.3 to 5.2 ± 2.9 (P > 0.05)] or 24 h glycaemic control/variability compared with CON. Seven days of bed rest led to ∼30-55% lower expression of genes involved in insulin signalling, lipid storage/oxidation and muscle protein breakdown, whereas no such changes were observed after 1 day of bed rest. In conclusion, more than a single day of physical inactivity is required to observe the insulin resistance and robust skeletal muscle transcriptional responses associated with bed rest and consequent alterations in energy balance.