Sistema inmunitario y suplementación de carbohidratos

Éste es el primero de tres artículos sobre el sistema inmunitario, ejercicio y macronutrientes. Hemos extraído la información del periódico “Exercise and Immunology Review” y hoy empezamos con carbohidratos y ejercicio de resistencia.

Los beneficios de los carbohidratos para ejercicio de resistencia están bien documentados y aceptamos por la comunidad científica. Para sesiones de entrenamiento y competiciones largas, nos recomiendan 30-60g/h hasta 90g/h para competiciones muy largas como Iron Man. La razón fundamental para estas cantidades es mantener el nivel de glucosa en la sangre, aunque también parece que los carbohidratos tienen un efecto indirecto en el sistema inmunitario.

Durante el ejercicio, las hormonas de estrés (adrenalina, noradrenalina y cortisol) aumentan. Estas hormonas perjudican al sistema inmunitario. Ponerse enfermo o tener una infección es algo bastante común entre los atletas; estoy seguro de que has tenido que perder alguna sesión de entrenamiento por esta razón.

En general, no hay una diferencia notable entre una dieta habitual alta o baja en carbohidratos y su efecto en el sistema de inmunitario, es decir, con ambas dietas hay una depresión de la función inmune después de ejercicio. Pero suplementación de carbohidratos durante ejercicio sí que tiene un efecto sobre él.

Durante ejercicio, mientras el nivel de glucosa en la sangra baja, el nivel de cortisol aumenta. El cortisol estimula el catabolismo de proteínas y la gluconeogénesis (la creación de glucosa de fuentes que no son carbohidratos). También tiene efectos anti-inflamatorios e inmuno-depresivos. Hay una buena cantidad de evidencia que demuestra que con la suplementación de carbohidrato durante ejercicio de resistencia el aumento del cortisol está atenuado. Por otro lado, también existen estudios que demuestran un efecto positivo de los carbohidratos en el sistema inmunitario, independientemente del nivel del cortisol.

En resumen: la suplementación de carbohidrato durante ejercicio parece a disminuir la depresión de la función inmunitaria después de ejercicio. Por desgracia, esta suplementación NO parece a reducir la incidencia de las infecciones de tracto respiratorio superior, si no que el efecto es sobre otro tipo de infecciones.

Aplicación practica    

A pesar de que la suplementación de carbohidrato no nos protege contra las infecciones de tracto respiratorio superior, todavía tiene un efecto beneficiario en el sistema inmunitario durante ejercicio. Eso significa que puedes recuperar de una ITRS más rápido y evitar otras infecciones. Por otra parte, el link entre carbohidratos y sistema inmunitario demuestra que mientras estás siguiendo una dieta baja en carbohidratos o estás entrenando en ayunas no es recomendable sesiones de entrenamiento de alta intensidad. Tampoco os recomiendo seguir una dieta baja en carbohidratos o entrenar en ayunas tras un período de entrenamiento muy duro.

Reference

Berman S et al. (2017) Immunonutrition and Exercise Consensus Statement. Exercise and Immunology Review: Vol 23

Carbohydrate supplementation and the immune system

This is the first of three short blogs taken from the latest Exercise and Immunology Review. We will be looking at the effect of the macronutrients on exercise and the immune system. Up first, we have carbohydrate and endurance exercise. 

From the point of view of performance, the benefit of carbohydrate during endurance exercise is well established. During long training sessions and competitions, the recommended amount of carbohydrate is between 30-60g/hr and up to 90g/hr for very long events such as Iron Man. The primary aim of ingesting this amount of carbohydrate is to maintain blood glucose levels but it appears that it also has an indirect effect on the immune system. As we exercise, we increase the level of stress hormones within our body (adrenaline, noradrenaline and cortisol) and these hormones impair immune function. Illness and infections are common among athletes and I am sure we have all experienced the inconvenience of having to cut our training short due to illness. While following an habitually high carbohydrate diet does not seem to have much of an effect on immune function compared to a low carb diet, in other words, they both show similar levels of post-exercise immune depression, supplementing with carbohydrate during exercise does have an effect.

As plasma glucose falls during exercise, plasma cortisol rises. Cortisol stimulates protein catabolism and gluconeogenesis (formation of glucose from non-carbohydrate sources), it also has a potent anti-inflammatory and immune depressive effect. While there is sufficient evidence to show that supplementing with carbohydrate during endurance exercise attenuates the body’s cortisol response through maintaining plasma glucose levels, there are also reports of carbohydrate having a beneficial effect on immune function regardless of plasma cortisol levels. Simply put, carbohydrate supplementation during exercise appears to diminish the post exercise reduction in immune function. However, the catch is that the benefit of carbohydrate supplementation on immune function doesn’t appear to have an effect on the incidence of URTIs otherwise known as a cold.

The practical application

Whilst it appears that supplementing with carbohydrate may not lessen your chances of catching a cold, it does help to keep your immune system functioning when faced with the stress of exercise. This is obviously useful in terms of recovery from URTIs and fighting off other infections. I would also consider the link between carbohydrate and immune function when planning training sessions and would avoid any high intensity work during periods of low-carb or fasted training. I would probably also avoid placing a period of such training immediately after a block of high intensity training.  

Reference

Berman S et al. (2017) Immunonutrition and Exercise Consensus Statement. Exercise and Immunology Review: Vol 23

How Much Carbohydrate Do We Need (For Sports) ?

In sports nutrition, whatever the question is, the answer is usually, “it depends”. While this answer may seem very vague there really is not a one size fits all approach to nutrition and especially to sports nutrition. When it comes to how much or how often you should eat carbohydrate, protein, fat etc. etc. it really does depend on how often you train, the intensity you train at and the type of activities you do. When it comes to planning your nutrition for sport, you must think about the amount of carbohydrate you need.

Carbohydrate is the fat of the 21^st century! All our food woes are the fault of carbs and all our ills will be cured by removing carbs from our diet. Of course I’m (slightly) exaggerating here but carbohydrate has got a pretty bad reputation at the moment.

If your goal is to lose weight, reduce body fat and so on then adopting a low carbohydrate diet is worth considering. However, as covered in our previous post about low-carb diets, if you regularly practice a sport that has periods of high intensity effort then carbs are your friend. 

How much you need depends on several factors including but not limited to:

• Type of exercise you do
• Intensity
• Frequency
• Duration
• Recovery 

Another important point to remember when thinking about carb intake is, where are you in your training programme? We all know the importance of periodisation when it comes to your training, well the same must be taken into account when thinking about your nutrition. Your nutrition needs will not be the same for a leg session in the gym as they would be for a 130km bike ride so it is important to match the nutrition to the exercise.

Below are some tables that are a useful guideline to refer to when thinking about your carbohydrate needs. Of course these are guidelines and not set in stone but they are a good starting point for you when you think about planning your pre/during/post training meals. 
  
Obviously if you are currently going through some fasted training and/or are trying to reduce body fat, increase fat oxidation etc. these tables may not be appropriate. 
They are aimed at people who are currently in or are about to enter into a block of training with medium to high intensity.

The tables have been adapted from the ACSM publication “Nutrition and Athletic Performance” which can be found here

If you want to know more about planning your diet for your exercise needs, please get in touch via our website, Twitter or Facebook. 
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General Carbohydrate Needs Depending on Intensity of Exercise 

 Fuelling Strategies for Pre-Exercise 

 Carbohydrate Needs During Exercise 

 

Cantidad de proteina necesaria para una buena dosis de leucina

En nuestro post sobre proteína después del ejercicio te hablamos sobre la importancia del amino ácido leucina. Este amino ácido es un componente clave para la síntesis de músculo. La evidencia científica más actual nos asegura que con cantidades de leucina de 20-45mg por kg de peso corporal, la síntesis de músculo está optimizada^1,2. 

Pero no caigas en la trampa de “más es mejor” y pienses que más leucina te va convertir en Arnold Schwarzenegger!. Parece que hay un límite de ingesta-síntesis de proteína con lo que cantidades de leucina de más de 45mg/kg no son beneficiosas³.

Aquí abajo está la tabla³ utilizada en el estudio de Moore et al. ¹ y Pasiakos et al. ² que nos ofrece consejos prácticos de cantidades de proteína que necesitamos para obtener 45mg de leucina por kg de peso corporal. 

Utiliza esta tabla como una guía cuando planifiques tu comida después del ejercicio para conseguir una dosis óptima de leucina.

Si quieres saber mas sobre nutricion y actividad fisica escríbenos a info@gabinetederueda.es

www.gabinetederueda.es 

References 
1.Moore, D. R., M. J. Robinson, J. L. Fry, J. E. Tang, E. I. Glover, S. B. Wilkinson, T. Prior, M. A. Tarnop-olsky, and S. M. Phillips. 2009. Ingested protein dose response of muscle and albumin protein synthesis after resistance exercise in young men. American Journal of Clinical Nutrition 89 (1): 161–168.

2.Pasiakos, S. M., H. L. McClung, J. P. McClung, L. M. Margolis, N. E. Andersen, G. J. Cloutier, M. A. Pikosky, J. C. Rood, R. A. Fielding, and A. J. Young. 2011. Leucine-enriched essen­tial amino acid supplementation during moderate steady state exercise enhances postex­ercise muscle protein synthesis. American Journal of Clinical Nutrition 94 (3): 809–818.

3.B.I Campbell 2014, Sports Nutrition: Enhancing exercise performance. CRC Press