Mostrando entradas con la etiqueta Iron Man. Mostrar todas las entradas
Mostrando entradas con la etiqueta Iron Man. Mostrar todas las entradas

miércoles, 13 de noviembre de 2019

Has the Game Really Changed?

You know a nutrition documentary is making a big splash when your friends start texting you to ask for your opinion. As most nutritionist/dietitians will agree, generally, your friend's interest in nutritional science will end at what is going to help them look good on the beach that summer or make them stronger/faster in their chosen sport.
 We had originally planned to give the documentary The Game Changers a miss, not because we have anything against vegetarianism or veganism, or to use the new trendy term "being plant based", in fact, quite the opposite. We often promote on our social media "meat free" days and are constantly badgering our patients to reduce their animal products in favour of vegetables and legumes. No, we didn't want to watch the movie because we suspected it would be a series of anecdotes passed off as "proof" that a plant based lifestyle is the ONLY way, and that if you don't convert right now you are evil and you will die when you're 50, if you're lucky.
 However, when a friend is asking your professional opinion you can't reply "sorry mate, I couldn't be bothered to watch it", and then be expected to be taken seriously at a later date.
 Before we get stuck in, I would like to point out that this review will not be an in-depth look at the studies and evidence that were put forward during the documentary. That has already been done quite extensively and so there's not much point in repeating ourselves. Further more, most people, who only have a passing interest in nutrition, are not going to want to hear all about research and statistical analysis. It is our job as nutritionists/dietitians to take that information and put it into "normal" language.
 With that in mind, if you do in fact want to look at the science in a more in-depth way, I would recommend going to Asker Jeukendrup's site where you will find a great critique of the evidence featured in the documentary.
 This review will be more of an overview of the documentary as a piece of film and the reason why, as someone who works in sport nutrition, I found it so infuriating.

The documentary taken purely at face value is brilliant. It is entertaining, emotive, thought provoking and motivational. It is really well shot and the narrator's journey from injury to recovery is fascinating. The athletes featured are all really interesting and to choose sports such as Strongman or American football, as opposed to Yoga, the stereotypical domain of the "whimpy vegan", was a very clever move from the directors of the film. And to top it all off, Arnie is in the movie! Who doesn't love Arnie???

 Where the wheels started to come off was when the coaches and Drs said things like "sport nutritionists say we have to eat meat" or "sport nutritionists say we need protein for energy". I was immediately confused because both of those statements were totally false. Anyone with even the most basic knowledge of nutrition would know that protein is not our primary energy source. And nor I, nor any nutritionist I know, have ever told anyone that they must eat meat.
 As the movie progressed it started to appear that it was advocates of the plant based lifestyle Vs sports nutrition of 30+ years ago. It didn't surprise me in the slightest when Arnie, a 72 year old man, described how he thought that he had to eat meat to hit his protein targets. Let's not forget that his pro bodybuliding career was from 1968 to 1980. You would hope science had moved on a fair bit in 40 years.
 The film makers then reveal that carbohydrate from plants and not protein from animals is the main fuel source for athletic performance as if they have just revealed the biggest kept secret in human history. Again, this puzzled me because this was nothing new, a quick browse through any sport nutrition literature would tell you exactly the same. But the film makers don't mention up to date sport nutrition. Instead they quote some German bloke from the 19th century who said vegetarians could never be athletes. A shocking statement yes, but also one that has nothing to do with modern sport nutrition. Pick any topic in science and compare it to what people thought 200 years ago and yes it's interesting and quite probably shocking but it has little to do with science in the 21st century.
 And then if going back 200 years wasn't enough, we do the inevitable trip back 100,000 years to our Paleo ancestors. And guess what? Turns out we didn't eat that much meat after all.
 It is fairly logical that when we had to spend time and energy to catch, kill and butcher our meat instead of just going down the shops, we wouldn't have eaten that much of it. Instead we relied more on fruits, vegetables and nuts for our energy source. That doesn't mean we didn't eat any meat at all. If we never ate meat we wouldn't have evolved the ability to eat meat. Next time you're down the park have a chew on some grass and see what happens. That is what happens when you eat something you're not supposed to.
 Apart from having little if anything to do with modern humans, no one in the sport nutrition world, at least nobody credible, is saying that human beings are carnivores.
 This leads nicely to the next point which, as infuriating as I find it, I must admit, this film is not the only one guilty of this. The constant comparison between a human and either the lion or gorilla to make a point about what we should or shouldn't eat is plainly ridiculous! You may as well compare us to trees and suggest we just stand in the sun all day. We are humans, not lions, not dogs, not gorillas, not sharks. We have all evolved on very different paths and so making comparisons is just a waste of time.

Moving away from the attack on outdated nutritional science onto the athletes themselves and things are not much better. This is probably the part of the movie that shocked me the most. No, not the fact we see plant based athletes exist, because again, we all knew that. What really shocked me was how appalling most of the diets of the featured (non-plant based) pro athletes were. I couldn't believe it when one of those pro American footballers was describing how his diet basically consisted of KFC. Or when the Titans guys were saying their pre-game meal was mountains of steak. As mentioned before, a big dollop of protein pre game is neither what is needed nor what is recommended, so I was totally flabbergasted that a sport as rich as American football had such poor sport nutrition support. Its not surprising at all that once you take somebody off a junk food diet they feel better. Hardly groundbreaking stuff that one.
 We see the same story with the firefighters, who were mostly overweight and pretty unhealthy looking, they were taken off their dreadful diets and shock horror, they felt better. 
Returning to steak, we got a little snap shot of everybody's favourite pantomime villain, Connor Mcgregor, and how his pre fight diet of 3 steaks a day backfired (who saw that coming?) and his plant based opponent, Nate Diaz, had more energy in the tank and eventually beat him. While it is not directly mentioned, it is heavily implied that because Diaz is plant based he won that fight. Again, what the standout message for me here was not Diaz being plant based but how Mcgregor was allowed or advised to eat nothing but steak before a fight. Yes, it sounds good in the press conference but in reality it is not going to help you much when your muscles are screaming for energy and you've hindered their ability to utilise glycogen through going low-carb. If McGregor had a sport nutritionist for that fight, something I doubt, I hope he fired him/her afterwards.
 Then we move on to Dotsie Bausch, the Olympic track cyclist, and we are told how she went through a transformation after leaving meat out of her diet. We see images of her smashing it in the gym and speeding round the track, whilst she describes how proud she felt "stood on the podium with a medal round her neck" at the 2012 Olympics. Now, to the majority of the viewers of this documentary they will probably think that she came away as Olympic champion. The choice of words and the editing of the clips from the race certainly gave that impression. I remember as I was watching the movie I was thinking "hang on a minute USA didn't win the women's team pursuit in 2012". I know next to nothing about American football, and little more about MMA but cycling is my sport, so I knew something fishy was going off here. I paused the movie and double checked online for the result, and sure enough, USA were beaten in the final by Britain (1). By quite a margin as well, nearly 5 seconds. I'm not for one second saying Bausch didn't win because she was plant based, I'm saying the omission of the fact her medal was silver, still an unbelievable achievement, was a very strange decision by the film makers, especially after the song and dance they made about Diaz beating McGregor.. A silver medal at the Olympic games is something to be very proud of and a clear demonstration that yes you can be plant based and get to the very top. There was no need to edit it in such fashion to lead you to falsely believe she won. Of course they will argue they never said she won, but they didn't say she came second either.
 They also heavily imply that the sudden turn around of the Titans' fortunes is down to a load of their players moving to a plant based diet. At the risk of sounding like a stuck record, I would argue it is probably more to do with them moving away from a junk food diet.
An important point to remember whenever elite athletes are concerned, there is always an elephant in the room when it comes to their diet and/or training plans which renders their comparison to mere mortals like us utterly pointless. I'm sure you know what I mean, but if you don't have a quick read about about else Arine was taking bucket loads of, spoiler alert, it wasn't soy.

Putting to one side the smoke and mirrors of the movie makers, these stories of athletes are nothing more than anecdotes. They are the movie equivalent of "this worked for me so it must work for you", which, as powerful as these anecdotes are, and watching a vegan athlete lift 550kg is certainly powerful, they are nothing more than a demonstration that in those cases those particular athletes can achieve amazing feats whilst being plant based. That's it. Nothing more. They are not proof that every athlete on Earth should become a plant based one.
This is where I was really disappointed with the film. I felt like the film makers were more interested in attacking the Low-Carb (LCHF) movement and the American meat industry rather than putting together a really great, scientifically sound documentary. If instead of attacking the sport nutrition sector with 30 year old data they invited some of the top sport nutrition minds on the movie, such as Asker Jeukendrup or Louise Burke or even my old lecturer Nigel Mitchel, a sports nutritionist for EF cycling team and (wait for it) a vegan, they would have got a more up to date view that wouldn't have altered greatly an important message from the film, eat more plants! But instead, they decided to go full conspiracy theory and started comparing meat to tobacco with the end result of not only ruffling the feathers of most sport nutritionists worldwide, but also damaging the value of the documentary. What I can never understand about these nutrition zealots is, if their chosen diet or lifestyle is unquestionably "the right way", why don't they just let the science speak for itself instead of resorting to dodgy tactics? for example, it's funny how the film mentions "industry sponsored science" but fails to mention the director is a major share holder in a vegetable protein supplement company. I'm sure they just forgot.
 If as a consequence of this movie people reduce their meat intake and increase their vegetable intake then fantastic! There's very little argument to be had when it comes to the fact that we eat too much meat and not enough veg. But that doesn't mean we all have to go full vegan! Even the guest Drs on the film say "predominantly plant based", which is a fancy way of saying balanced diet. This evangelical approach that food documentaries are currently taking is exhausting. It was the same with the low-carb movies, it's the same with the vegan ones and I'm sure it will be same with the fasting ones. Be it with our food or our politics, we appear to be living in a time where we must be A or B, black or white, yes or no, fat or thin. We slap a label on ourselves and we won't even entertain the idea of taking a bit from column A and a bit from column B. All that these documentaries achieve with their cherry picked, one sided science is to create further mistrust and confusion between the general public and the nutritional science industry, which, in turn, leaves the door open for the real con artists and quaks, of which there are plenty.

So finally, has the "game" really changed thanks to this film? The answer is a resounding NO I'm afraid. The film did not show us anything that wasn't already known in the current world of sport nutrition. We know plant based athletes can make it to the very top, we know a diet of red meat is not good for athletic performance (or health) and we know most of the developed world eats too much meat. Their decisions to portray sport nutrition as an outdated meat obsessed cartel, to cherry pick data and stretch the truth with clever editing has utterly diminished the credibility of the film, which I think is a great shame.
The one ray of hope from this film is that many athletes still eat like teenage boys and so we sport nutritionists are still very much in need.


miércoles, 24 de enero de 2018

El gran error que tienes que evitar en Enero

Aquí estamos otra vez: un año nuevo, hace frío y nos sentimos gordos y feos porque hemos comido y bebido demasiado en Navidad. Internet está lleno de artículos, consejos y curas milagrosas para perder grasa, ganar músculo y arreglar todo.

No vamos a añadir nada a estas listas de curas pero te vamos a ofrecer un único consejo para tener en cuenta si quieres empezar una dieta o un régimen de ejercicio.

Si estás en dieta no empieces un bloque de entrenamiento duro o alta intensidad  
Es un error que comete mucha gente y (en nuestra humilde opinión) la principal razón por la que la mayoría de los “quiero ponerme en forma” fallan en febrero. Mucha gente ha pasado las Navidades bebiendo, comiendo y no haciendo casi nada de ejercicio,  y cuando llega al año nuevo empiezan una dieta muy estricta y se castigan en el gimnasio, todo a la vez. Normalmente estas rutinas tan duras ocasionan lesiones y enfermedades y no se pueden mantener más allá de unas semanas. 
Como hemos dicho anteriormente, tu nutrición tiene que estar adaptada a tu plan de ejercicio, es decir, si vas a empezar una rutina muy dura, tu cuerpo necesita los nutrientes necesarios para proporcionarte energía y hacer las adaptaciones necesarias, como aumentar el tejido muscular. Si tu cuerpo no tiene suficiente energía porque estás siguiendo una dieta muy estricta, no podrás hacer los ejercicios bien porque no tienes sustento y eso aumentará el riesgo de lesiones; tu sistema inmunitario tampoco podrá funcionar de manera óptima y te pondrás enferm@.  

Si quieres empezar una dieta, aquí tienes algunos puntos clave

  • Asegúrate de que mantienes una ingesta adecuada de proteína: 1,5 – 2g/kg de peso corporal 
  • Haz ejercicio de esfuerzo para mantener la masa muscular pero recuerda, nada de alta intensidad
  •  Si haces ejercicio de resistencia, que no sean de larga duración (más de una hora) o de alta intensidad (mayor que zona 3 - pulsaciones/vatios). 

Cuando hayas llegado a tu peso objetivo puedes aumentar la intensidad y empezar a entrenar más duro, pero siempre adaptando tu dieta a ello.

viernes, 12 de enero de 2018

The number one mistake to avoid when you start your January fitness regime

 Here we are again, its January, it’s cold and miserable and we all feel fat and ugly! After overindulging over the Christmas period we are all determined to get back in shape. 
The internet is currently awash with detox plans and miracle regimes to get everyone thin, fit and strong. 
We’re not going to add to the list but we are going to offer you a piece of advice that you should always take into account when deciding if you going to try to lose weight.

Do not start a block of hard training if you are dieting

This is a mistake people make over and over again and (in our opinion) why many “I must get fit” New Year’s resolutions fail around mid to late February. 
People will have spent most of December drinking and eating and probably not doing much exercise, and when January arrives they go on a strict diet and flog themselves in the gym. 
The usual result is they become either sick or injured and then the new regime falls by the wayside. 
As we have said previously you have to match your nutrition to your training needs. If you are going to start a very hard exercise regime, depriving your body of the necessary nutrients to provide energy and make the adaptations will result in, at best poor training sessions and at worst, getting sick and/or injured.

If you want to go on a diet some key points to remember are
  • Make sure you maintain an adequate intake of protein, 1.5-2g/kg of bodyweight
  • Make sure you do resistance training in the gym to maintain muscle mass (remember nothing crazy)
  • Keep any cardio work to a moderate intensity and duration
Once you have reached you goal weight you can start to increase the intensity of you fitness regime.

For any more questions regarding diet and exercise email 

jueves, 19 de octubre de 2017

¡¡Cuidado con las cañas después de entrenar!!

Todos nosotros, los atletas no profesionales (y algunos pros también), disfrutamos de una cerveza después de entrenar y sabemos que consumir alcohol en exceso es perjudicial para la salud. Pero ¿puede ser también perjudicial para nuestra recuperación? 

En este estudio de la universidad de North
Texas investigaron el efecto del alcohol después de una sesión de entrenamiento con pesas. Contaban 10 hombres y 9 mujeres, todos bien entrenados que hicieron 6 series de sentadillas y después tomaron alcohol o un placebo. Todos los participantes hicieron ambos: ejercicio y alcohol y en otro momento ejercicio + placebo. Los investigadores tomaron biopsias musculares antes del entrenamiento y tras 3 y 5 horas. Los investigadores esperaban encontrar proteínas asociados con el crecimiento celular y diferencias entre el grupo alcohol y el de placebo.

El principal hallazgo fue que en los hombres la fosforilación de la proteína mTORC1 (una proteína que está involucrado con el crecimiento celular muscular) fue atenuada con alcohol.

Los autores concluyeron que el consumo de alcohol puede influir negativamente en la recuperación, inhibiendo la proteína que permite que el músculo aumente de tamaño tras el entrenamiento con pesas (al menos en hombres).

Este es un artículo muy interesante. Nos advierte de que tomar esa cervecita tras el ejercicio, aunque apetecible, nos puede alejar de ese objetivo para el que hemos estado trabajando tan duro. Desde aquí nos preguntamos si el efecto sería el mismo tras realizar un ejercicio de resistencia. 

lunes, 18 de septiembre de 2017

Amino Acidos Ramificados: ¿Merecen la pena?

Los aminoácidos ramificados (también conocidos como BCAAs) son uno de los suplementos más populares, quizá más que la creatina. Siempre se ha dicho que los BCAAs son imprescindibles para los aficionados de entrenamiento de fuerza y resistencia, porque al parecer los BCAAs provocan un estado de anabolismo o impiden un estado de catabolismo.
Mientras la creatina tiene décadas de apoyo científico, ¿podemos decir lo mismo sobre los BCAAs?
En este post resumimos el artículo de Robert Wolfe de la publicación Journal of the International Society of Sports Nutrition. Te dejamos el original aquí (en inglés), te recomendamos que leas, aquí abajo tienes los puntos claves. 

Antes de que empecemos a repasar la evidencia, vamos a repasar brevemente qué son los aminoácidos. Hay en total 20 aminoácidos, 9 son esenciales y 11 no esenciales. Esencial quiere decir que nuestro cuerpo no los puede construir y tenemos que obtenerlos través de la dieta. De los 9 aminoácidos esenciales (AAE) 3 de ellos se llaman los amino ácidos ramificados o “branched chain” (BCAAs) son: leucina, isoleucina y valina. Las proteínas musculares están en un estado continuo de rotación, es decir, que siempre hay síntesis de proteínas musculares (SPM) y descomposición de proteínas musculares (DPM). Hay un estado de anabolismo cuando hay más síntesis que descomposición, y cuando pasa lo contrario lo llamamos estado de catabolismo. Se puede alcanzar un estado de anabolismo al aumentar SPM o al inhibir DPM, pero para la SPM hacen falta todos los aminoácidos.

La evidencia

  • En los estudios que demuestran un efecto positivo de la SPM los sujetos son ratas. Los estudios de músculos en ratas tienen casi ninguna relación con los estudios de músculos de los humanos.
  • En estos estudios, los BCAAs que les dieron a las ratas fue por la vía intravenosa, no vía oral, un método poco práctico en realidad.
  • En los estudios con sujetos humanos, también les dieron los BCAA por la vía intravenosa, pero esta vez hubo una disminución de la SPM.
  • En los estudios de humanos hubo también una disminución de descomposición (DPM) pero los sujetos se quedaron en un estado de catabolismo.  

Actualmente la evidencia sugiere que los BCAAs solos (sin otras proteínas, carbohidratos etc.) reducen la rotación de las proteínas musculares (síntesis y descomposición). El autor nos advierte que una reducción en la rotación de las proteínas musculares puede tener un efecto negativo en el esfuerzo del músculo debido a una reducción en la construcción de nuevas fibras musculares.
La evidencia actual indica que los BCAA (particularmente leucina) aumentan la señal de SPM, sin embargo, una señal más potente no significa más SPM si todos los AAE no están presente. Es como intentar arrancar un coche sin combustible.
Para conseguir la SPM necesitamos todos los aminoácidos. Después de una comida con proteínas, nuestro cuerpo puede utilizar los AAE de la comida, pero entre comidas, en el estado post-absortivo, la única fuente de AAE es a partir de la descomposición de las proteínas musculares, por eso la proteína del músculo está siempre en un estado de rotación.
Si tomamos una dosis de BCAA muy grande sí reducimos DPM, pero eso significa que estamos reduciendo la cantidad disponible de AAE, por lo que como resultado también reducimos la SPM.

El lado bueno (más o menos)

Con una señal de SPM aumentada gracias a los BCAA puede que, en combinación con una comida rica en proteína, el efecto de la proteína resulte aumentado. Un estudio ha demostrado que una dosis de 5g de BCAA en combinación con 6.25g de proteína de suero tenían el mismo efecto en la SPM que 25g de proteína de suero solo.  
Aunque esto es interesante, si pensamos en el precio de los BCAA en comparación con el precio de proteína de suero o mejor todavía, COMIDA, ¿merecen la pena los BCAA? Recuerda que más no es necesariamente mejor, si añades más BCAA a tu batido de proteínas no significa aún más SPM.
Otro punto a recordar, como decimos en nuestro blog de BCAA e inmunidad, es que los BCAA compiten por el mismo sitio de absorción y normalmente el aminoácido en mayor cantidad (casi siempre leucina) es absorbido a costa de los otros dos. 


No solo hay una falta de evidencia que demuestra un efecto anabólico de los BCAA solos. El autor concluye que sin la presencia de una fuente de AAE (a través la comida o de la DPM), no es posible para los BCAA aumentar la síntesis de las proteínas de musculares. Nuestro consejo es: olvídate de los BCAA y asegúrate de que tu dieta tiene una buena cantidad de proteínas de fuentes animales y vegetales.     

Si quieres saber más sobre nutrición deportiva visita nuestra web.   

jueves, 6 de julio de 2017

Energy Bar Recipe

Finding an energy bar that tastes good and is not full of rubbish has always been a huge challenge. I'm sure that I am not the only person who has ordered a large batch of energy bars for a cycling or training trip and then during a long ride as you unwrap probably the 20th bar you think "God! I am sick of this flavour!"

Taste fatigue is detrimental to both moral and performance. It may sound obvious but if don't like the flavour of something or you are sick to death of it, you will not eat it, which eventually leads to your performance suffering through lack of energy.
The finished article. 
Through years of trying several different brands of energy bars I have found that I really want them to taste like actual food and not a bunch of chemicals and flavourings. Eventually I decided to experiment with making my own bars.

The advantages of making your own bars are, you know exactly what is going into them, you can experiment with several flavours without having to buy lots of different types of bar, and generally speaking the cost of the ingredients will be cheaper than buying a box of energy bars from a well known brand.
I have always found that the energy bars you buy are very sweet so after 2 or 3  I get really sick of the flavour, especially if I am on a very long ride where I will be taking gels and sports drinks as well. By the end of the ride I am dying for something savoury!
With this recipe I have tried to find the right balance between carbohydrate for energy but not being too sweet. The great thing is that the recipe is pretty flexible so you can add or take away ingredients as you pplease to suit your taste preference. The only 3 ingredients that are essential are oil, oats and honey. This is the recipe to the bars I am currently taking out with me.

100mls oil. (I use sunflower oil just for the fact it doesn't really taste of anything, I have tried both coconut and olive oil and find the flavour overpowers the rest of the ingredients.)
225g of oats
210mls Honey (The reason I put mls here instead of grams is that I use a protein powder scoop to measure my honey, 210 mls is 3 big scoops or around 300g. Yes that is a lot of honey but these are energy bars for long days in the saddle.) 

The ingredients above form the base of the bars and should be included in whatever batch you make. With the following you can be pretty flexible and change depending on your preferences.

40g Almonds (chopped)
10-12 Dates (chopped) 
2-3 tablespoons of peanut butter (this takes a bit of the sweetness away from the honey and dates, make sure you use a brand of peanut butter that isn't full of palm oil and sugar. I use bulkpowders 100% peanut butter.)
30g 100% cocoa grated or in powder (again this takes the edge off the sweetness and gives the bars a nice chocolate hint)

Here is a picture of all the ingredients. 

Melted Honey


  • Preheat oven to 180C 
  • Place the oil in a saucepan and put on a low-medium heat (my electric hob is numbered 1-6 and I usually use 3) 
  • Add the honey and stir continuously until it has melted
  • Add the peanut butter and also stir until melted 
  • Once the both the peanut butter and honey have melted you can start to add your other ingredients and give them a good stir so they are totally covered by the mixture
  • Now you can start adding the oats. Add them a small amount at a time and make sure you keep stirring to get all the oats covered in the mixture. As you add more oats it will start to get thick and difficult to stir. At this point also add the cocoa. 
  • Transfer the mixture into a cake tin and place in the preheated oven for between 15-18 mins depending on how gooey you want your flapjacks. I usually take them out around 15 minutes.
  • Leave to cool. This may sound obvious but if you try and cut the flapjacks now they will just fall apart, I usually leave them overnight. 
  • Cut them up into sizes of your preference, I have recently started to cut them into smaller pieces as I have found it easier to eat in one go as opposed to taking a bite then putting it back in your pocket whist moving.

Adding the almonds and dates into the mixture  
Adding the oats 

Nutritional Info if you divide the finished block into 8 bars each bar contains 

  • Kcals 324
  • Carbohydrates 59g 
  • Sugar 36g
  • Fat 6g
  • Protein 6g  

For long endurance events, the magic number in terms of carbohydrate is 60g/hr which means one of these bars an hour should do the trick in meeting your carb needs. 

If you try this recipe please let us know in the comments section how you get on, or you make any tweaks 

viernes, 28 de abril de 2017

Excercise, Macronutrients and immunology part III Protein and Amino Acids

As the debate about fat and carbohydrate rages on, I think everybody can agree that protein is essential. Even the moderately active individual needs to have a higher than recommended protein intake. This is the final article that summarises the latest evidence on the role of the macronutrients in exercise and immunology (click here and here to read the previous two articles). The article will not look at protein as a whole but on the amino acids that have been researched the most in terms of their effect on the immune system post exercise. These amino acids are the branched chain amino acids (BCAA) and glutamine. Remember that if you want to read about this topic in more detail please consult the Exercise and Immunology review1.

The branched chain amino acids (leucine, isoleucine and valine) are probably one of the most popular sports nutrition supplements, especially among people who regularly lift weights. During long bouts of exercise the BCAAs are utilised by the working muscles and this causes the plasma concentration of BCAA to fall. Apart from being used for energy, the metabolism of BCAA produces nitrogen which is used for glutamine synthesis. During exercise, a reduction in plasma glutamine has been observed which has been linked to exercise-induced immunodepression. 
It was suggested that BCAA intake could indirectly influence immune response by increasing glutamine synthesis. As we all know, just because something sounds good in theory doesn’t mean it will work in practice. Despite the fact that supplementing with BCAA during exercise did indeed increase both plasma and muscle concentrations, this did not lead to an increase in plasma glutamine. 
There is some evidence that chronic supplementation of BCAA can prevent the decrease in plasma glutamine and other markers of exercise-induced immunodepression.
BCAA, in particular leucine, may have a direct effect on the immune system through their effect on the mTor signalling pathway. mTor stimulates muscle protein synthesis and activates cytokine and antibody production. Again, somewhat predictably, the evidence is lacking and what data there is indicates that BCAA has a greater involvement in muscle protein synthesis as opposed to immune function.

The authors conclude that there is some evidence that BCAA can reduce exercise-induced immunodepression but not enough to recommend its use for athletes in the context of immune function.

It is worth remembering that the BCAA use the same transporter during digestion and that when they are taken in large amounts (for example as a supplement) the amino acid that is in the highest concentration (usually leucine) is absorbed at the expense of the other two2. Therefore, I would suggest that BCAA supplementation in general may not be as advantageous as diet rich in high quality proteins.

Moving away from BCAA as a precursor to glutamine and to glutamine itself. Glutamine is the most abundant amino acid in the body and was originally thought to be non-essential. However, during times of stress to the body the requirement increases so it has been renamed conditionally essential. It is synthesised, stored and released mainly in the skeletal muscle, and among the numerous cells that utilise it are the immune cells, such as, macrophages, neutrophils and lymphocytes. As mentioned before, prolonged exercise results in a decrease in plasma glutamine concentration, a decrease in immune function is simultaneously observed.

As with BCAA supplementation, the rationale is sound but disappointingly, the results from studies of glutamine supplementation do not live up to the expectation.
In conclusion, while there are some encouraging signs that BCAA and glutamine may influence immune function, the evidence is not currently strong enough to promote the supplementation of either. As I stated before, what is essential is that you have a diet rich in high quality protein. 
Before even considering supplementation of any kind you should always evaluate the quality of your diet and address any issues. If you would like to know more about our sports nutrition packages please contact us on 

1.Berman S et al. (2017) Immunonutrition and Exercise Consensus Statement. Exercise and Immunology Review: Vol 23
2. Gropper, S.S & Smith, (2013) J.L Advanced Nutrition and Human Metabolism 6th Edition. Wadsworth Cengage Learning 

viernes, 24 de febrero de 2017

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.

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