Mostrando entradas con la etiqueta Low carb. Mostrar todas las entradas
Mostrando entradas con la etiqueta Low carb. 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 https://www.mysportscience.com/ 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.


1. https://en.wikipedia.org/wiki/Cycling_at_the_2012_Summer_Olympics_%E2%80%93_Women%27s_team_pursuit

viernes, 25 de octubre de 2019

Dietas bajas en carbohidratos y altas en grasa en deportes de resistencia: un repaso a la evidencia

No es sencillo informarse sobre las dietas bajas en carbohidratos y no perderse en un montón de anécdotas o peor, encontrarte en medio de una pelea de Twitter. Hay pocos temas en el mundo de la nutrición que causen tanto revuelo.

Mi interés personal en las dietas bajas en carbohidratos y altas en grasa (LCHF) se debe a su aplicación en deportes de resistencia.

Sería un sueño hecho realidad el poder utilizar las más de 100.000 kcal de grasa que están almacenadas en nuestro cuerpo. Pero como casi con todo lo relacionado con la nutrición, no es tan simple como nos gustaría.

Antes de que examinemos la evidencia, quiero aclarar que no estoy hablando sobre “LCHF” y composición corporal o sensibilidad a la insulina, sino solo examinando si una dieta baja en carbohidratos y alta en grasa te hace un mejor corredor, ciclista o triatleta.

En este post voy a resumir un artículo de Louise Burke que se llama “Re-examining High-Fat Diets for Sports Performance: Did We Call the "Nail in the Coffin" Too Soon?". El artículo original es en inglés, te recomiendo que lo leas. Lo puedes encontrar aquí. Abajo he traducido los puntos claves.

Es globalmente aceptado que una dieta LCHF de corta duración (menos de 3 días) es perjudicial para el rendimiento debido al agotamiento de glucógeno de los músculos y del hígado, y que no se produce un aumento de oxidación de grasa. Sin embargo, existen resultados interesantes si se sigue una dieta LCHF durante mucho tiempo.

Después de un repaso extenso de los artículos existentes desde 1980 hasta 2006, los resultados claves del autor son:

  • Seguir una dieta LCHF sin cetosis puede causar adaptaciones claves en los músculos en tan solo 5 días. Esto incluye un aumento de triglicéridos intramusculares y de la actividad de la enzima lipasa hormono sensible (LHS) que moviliza los triglicéridos de los músculos y el tejido adiposo. Con estas adaptaciones el/la atleta puede aumentar su oxidación de grasa. 
  • Estas adaptaciones persistirían a pesar de realizar 1-3 días de carga de carbohidratos. Aunque la velocidad de utilización de grasa sería menor en comparación con una dieta LCHF, sería más alta que con una dieta alta en carbohidratos.
  • La exposición crónica a una dieta LCHF causa una regulación a la baja en la utilización de los carbohidratos, específicamente del glucógeno de los músculos, durante ejercicio. Esta regulación a la baja persiste durante el ejercicio de alta intensidad, incluso en estudios con una dieta LCHF seguido por una carga de carbohidratos.
  • A pesar del aumento en la capacidad de utilizar esta fuente de combustible, las estrategias de LCHF no han dado lugar a una mejora del rendimiento en deportes de resistencia. Las mejoras se han limitado a estudios con protocolos de ejercicio sub-máximo, que no son un fiel reflejo de los deporte de resistencia.
  • Es posible que las estrategias LCHF puedan perjudicar rendimiento, específicamente deportes que tienen intervalos cortos de esfuerzas de alta intensidad. Esto es probablemente debido a una disfunción en la utilización del glucógeno por parte del músculo.

La autora escribió que debido al reciente aumento de popularidad de las dietas LCHF, había vuelto a examinar la evidencia disponible. Sin embargo no pudo encontrar estudios recientes que justificaran la avalancha de popularidad. De hecho sólo encontró dos estudios con atletas, desde 2006, y ninguno mostró una mejora del rendimiento. Sin embargo lo que sí que mostraron fue un pequeño pero favorable cambio en la composición del cuerpo debido a una reducción de grasa corporal.

La autora afirma que la mayor parte del apoyo a las dietas LCHF se encuentra en los medios de comunicación social, como por ejemplo, Twitter. También que en general está relacionado con atletas que no son de elite y que son historias de tipo anecdótico.
La conclusión de la autora es que en lugar de un “pensamiento en blanco y negro”, los investigadores y profesionales deberían moverse hacia protocolos individualizados cuando trabajen con atletas.


Mis pensamientos


Creo que Louise Burke ha escrito un artículo muy interesante y lleno de sentido; estoy de acuerdo con que deberíamos mantener una actitud más flexible y que el dogma no ayuda a nadie.

En el pasado se pensaba que las dietas altas en carbohidratos eran la única dieta que se podía seguir si querías participar en los deportes de resistencia. Ahora, sin embargo, parece que algunos se han ido al extremo opuesto y defienden que sólo se debe seguir una dieta LCHF.
Personalmente veo los beneficios de limitar de vez en cuando la ingesta de carbohidratos, especialmente si quieres reducir la grasa corporal. Pero lo cierto es que la evidencia demuestra que si quieres rendir bien en un ejercicio de alta intensidad, seguir una dieta crónicamente baja en carbohidratos sería perjudicial.



Si quieres que te ayude a planificar tu entrenamiento deportivo, escríbeme a wayne@gabinetederueda.es

lunes, 25 de junio de 2018

Gluten Sensitivity: Does it really exist?

In previous articles we have explained the difference between coeliac disease, wheat allergy and a third condition known as Non-Coeliac Gluten Sensitivity (NCGS). To briefly recap, as the name suggests, NCGS appears to be a condition where people who are neither coeliac nor allergic to wheat still report symptoms of bloating, loose stools etc. when consuming gluten containing foods. The mechanisms behind the condition are unclear, the immune system doesn’t appear to be involved but some researchers have suggested that NCGS may be a step along the path towards coeliac disease (1). Whilst we were completing the Monash FODMAP course another possible explanation was put forward to explain why people who have no immunological response to gluten still report gastrointestinal issues when eating gluten containing foods. What was interesting was that the explanation called into question the very existence of the condition of NCGS.
In recent years gluten free eating has become very popular and lots of pseudo-conditions are attributed to gluten. Although NCGS isn’t what we would call a pseudo-condition it has been proposed that it might be part of IBS and the culprit isn’t gluten after all. 

Fructans are chains of varying length of the sugar fructose, they are universally malabsorbed because we do not have the required enzyme in our body to break the chains into smaller fructose units. This leads to the fructans passing to the large intestine where they are fermented by the resident bacteria. This fermentation and the resulting gas production is usually well tolerated by non-IBS people but people with IBS tend to be highly sensitive to the fermentation of fructans and experience painful bloating and bowel distention. Foods that contain fructans are vegetables such as onion and garlic and of course wheat.
Monash University state that there is a lack of evidence that has managed to separate the effects of gluten from fructans so it is unclear which food component they are reacting to. Therefore, they do not recognise NCGS as a condition in itself and propose that people who report problems with gluten may in fact be IBS sufferers reacting to the fructans in wheat (2).
Now, this all sounds well and good, people can now relax and realise they weren’t sensitive to gluten after all. However, the problem lies in the practicality of it all. Finding a food that contains gluten but no fructans is virtually impossible, the only one we have found so far is sourdough bread or “masa madre” as it’s known here in Spain. During the fermentation process of sourdough bread, microorganisms such as Lactobacilli feed on the fructans and reduce their content in the finished product. The end result is that people who previously thought they were gluten-sensitive could enjoy sourdough bread, providing coeliac disease has been correctly excluded.

In conclusion, it appears that there is a lack of strong evidence to declare that NCGS is a condition in itself and people who report symptoms may be in fact IBS sufferers who are particularly sensitive to fructans. Aside from wheat, people who suspect they may fall into this category also need to keep in mind, onion, garlic, leeks and chickpeas.
For any more information on IBS or the Low FODMAP diet please get in touch via info@gabinetederueda.es

References 
1. Francavilla MD, et al. 2014, Clinical, Serologic and Histologic Features of Gluten Sensitivity in Children. The Journal of Paediatrics; 164: 463-7

2. https://www.monashfodmap.com/blog/the-truth-behind-non-celiac-gluten/ 



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 info@gabinetederueda.es 

miércoles, 20 de septiembre de 2017

An Introduction to Periodised Nutrition

If you regularly read articles about training or subscribe to any of the millions of training magazines, you will almost certainly be familiar with the term “periodised training”. Basically, it means instead of doing the same thing day in day out, you plan your training sessions to ensure you reach your optimal state of fitness for your given sport at the right time. As with most ideas regarding training it has been tweaked over the years and now we have versions such as, inverse periodisation, block periodisation so on and so on, but the idea remains the same, plan your training.

When people ask me how much carbs/protein/fat they should eat I always answer, “it depends on your training”. Initially they think I have given them a rather vague and unhelpful answer, but once I explain that their nutrition should match their training and go into detail they understand why I gave that answer.
This is the concept of periodised nutrition, depending on the type/duration/intensity of your training regime determines what you should eat. This is one of my main arguments against the LCHF craze, if during your training regime you have any periods of high intensity training or races, then chronically following a low carb diet will not be of much help. Of course, the opposite is true. If you are not doing any kind of intense or long duration training then a high carbohydrate diet is not necessary.

A good example would be somebody training for an Ironman, whilst the event is still several months away and they are wanting to optimise their fat utilisation capacity, they will most likely be doing sessions of fasted training or sessions of fairly low intensity. At this point, I would recommend a diet low in carbs with higher fat. Once they got nearer to race day and the intensity of training increased, I would increase the amount of carbohydrate in their diet. And of course, for the event itself, ensuring they take on plenty of carbohydrate will be vital.
In summary, your diet should provide fuel for your training and your recovery, the more intense your training is the more you will need carbohydrate in your diet.

Over the next few months we will be looking in-depth at different strategies of periodised nutrition, but in the meantime any questions or comments leave below or contact www.gabinetederueda.es

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. 

Conclusión

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. www.gabinetederueda.es   

lunes, 11 de septiembre de 2017

BCAAs: Are they really worth it?

Branched chain amino acids (BCAAs) are in some way the creatine of the 21st century, what I mean by that is, that they have become the “go to” supplement for every gym goer. Strength and endurance enthusiasts alike are sold the idea that BCAAs are an essential component of their nutrition regime because they supposedly induce an anabolic/avoid a catabolic state in humans.
Whereas creatine now has decades of convincing research behind it, can we really say the same about BCAAs?
This post will summarise the recent review by Robert Wolfe in the Journal of the International Society of Sports Nutrition. I strongly recommend that you read the full paper (link here) after you have read the main points below.

First, a quick recap on amino acids. There are 20 amino acids in total, 9 are essential and 11 are non-essential. The term “essential” means that the body cannot synthesise these amino acids so we must obtain them from food. Of the 9 essential amino acids (EEAs) 3 of these are called the branched chain amino acids (BCAAs) these are, leucine, isoleucine and valine. 
Muscle protein is in a continued state of turnover, meaning proteins are constantly being broken down and synthesised (built up). The term anabolic state refers to when muscle protein synthesis (MPS) is greater than muscle protein breakdown (MPB), in other words, our muscle tissue is being built up as opposed to being broken down. When muscle protein breakdown is greater than synthesis this is known as a catabolic state. The anabolic state can be achieved by either increasing muscle protein synthesis or by reducing muscle protein breakdown. For MPS to be greater than MPB all 20 amino acids must be present.

We are sold BCAAs under the premise that they stimulate muscle protein synthesis and so we can avoid the dreaded catabolic state. But what does the actual evidence say?


The Evidence 

  • The studies that show an increase in MPS after ingestion BCAAs were conducted on rats. Muscle protein studies on rats have little if any relevance to humans.
  • These studies also administered the BCAAs intravenously as opposed to orally
  • Studies on humans, (who also administered the BCAAs intravenously), actually showed a decrease in MPS
  • The human studies also demonstrated a decrease in muscle protein breakdown but overall net effect was that the subjects remained in a catabolic state. 

When all the evidence is considered, it appears that taking BCAAs alone reduces protein turnover (synthesis and breakdown). The author points out that this may have a negative effect on muscle strength due to a reduction in new muscle fibre construction.
Current evidence suggests that BCAAs (in particular leucine) increase the “signal” for MPS, however an increased signal will not lead to increased MPS if the other EAAs are not available. Think of it as turning the key in the ignition, without fuel the engine won’t start.
In order for MPS to occur all amino acids must be available. After a meal containing sufficient protein, MPS is achievable because the EAAs will be taken from the ingested food. However, in the post-absorptive state (in between meals) the only source of EEAs is from the breakdown of muscle protein. This is why muscle is in a constant state of turn over.
If we take a huge dose of BCAAs we reduce MPB, however, by reducing MPB we reduce the amount of EEAs available for MPS so in turn, both MPS and MPB are reduced.

The Good News (kind of) 

With an increase in anabolic signalling through BCAAs, it appears that it can increase the effect of a protein meal. One study demonstrated that 5g of BCAAs added to 6.25g of whey protein had the same effect on MPS as 25g of whey protein alone.
While this may seem interesting, when you weigh up the cost of BCAAs against the cost of whey protein or (shock horror) real food, are they really worth it? Remember the golden rule, more is not always better, so adding even more BCAAs to your shake will not have a greater effect on MPS.
Another point to remember is, as we mentioned in our amino acids and immune system post, the BCAAs compete for the same site of absorption so when taken in a large dose the amino acid in the greatest concentration (usually leucine) will be absorbed at the expense of the others. 

Conclusion 

Not only is there a lack firm evidence to demonstrate an anabolic effect of taking BCAAs alone, the author concludes that without a supply of essential amino acids (either through food or muscle protein breakdown) it is not possible for BCAAs alone to increase muscle protein synthesis. Our advice as always is ensure you have a diet rich in high quality protein before starting to consider supplements. 

For more info please see www.gabinetederueda.es 

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 info@gabinetederueda.es 

References 
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.

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