Mostrando entradas con la etiqueta Vegetarianos. Mostrar todas las entradas
Mostrando entradas con la etiqueta Vegetarianos. 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

miércoles, 16 de mayo de 2018

¡Terminamos el curso de FODMAP de la universidad Monash!


Grandes noticias!! Hemos terminado la especialización del manejo del síndrome de intestino irritable (SII) tras completar el curso de la universidad Monash titulado “La Dieta Baja en FODMAP para Síndrome de Intestino Irritable”. 

La Universidad de Monash es el pionero en el manejo y tratamiento de SII con una dieta baja en carbohidratos rápidamente fermentables que se llaman “FODMAP”. Tras completar este curso podemos ofrecer un tratamiento basado en evidencia científica para personas que tienen problemas como dolor abdominal, gases e hinchazón. 



Si quieres saber más sobre la dieta FODMAP haz clic aquí o si crees que esta dieta te ayudaría escribanos en info@gabinetederueda.es 

jueves, 16 de noviembre de 2017

La vitamina del sol

Seguro que todos hemos oído hablar de la vitamina D. Nuestro cuerpo la fabrica cuando exponemos nuestra piel directamente a la luz solar, fuera de casa y sin crema protectora, durante unos 10-15 minutos, al menos los brazos. Tenemos que tener cuidado de no quemarnos y ¡de no exponernos más de este tiempo sin crema solar! 

También podemos obtener Vitamina D a partir de ciertos alimentos como pescado azul, carne roja, hígado, huevo y alimentos enriquecidos como la leche, pero en cantidades tan bajas que la luz solar se ha convertido en nuestra principal fuente para llegar a las cantidades adecuadas.

La vitamina D, además de ayudarnos a absorber calcio para mantener unos huesos y dientes fuertes, fortalece el sistema inmunitario, participa en el desarrollo del cerebro y en la función muscular y cardíaca. También parece que juega un papel importante en la prevención de caídas en ancianos (1) y el la aparición del Alzheimer (2). 

Varios factores ambientales, como la latitud o las condiciones meteorológicas, determinan si el sol puede estimular la conversión en la piel de 7-dehidrocolesterol a pre-colecalciferol. Los atributos personales, como la pigmentación de la piel, edad, vestimenta, protector solar, entorno de trabajo y la actividad física también pueden dificultar la síntesis de vitamina D.

Por lo general, en España, tendemos a no preocuparnos de la vitamina D, ya que difícilmente podemos encontrar un país en Europa tan soleado como el nuestro! Pero la realidad es que la deficiencia de Vitamina D que se extiende por nuestros países vecinos también nos afecta a nosotros. Varios estudios han presentado datos que demuestran que en España tenemos alrededor de un 33% de deficiencia de vitamina D (3, 4, 5). 

Existe en la actualidad el Projecto ODIN, que aspira a poder enriquecer los alimentos de uso diario con vitamina D para asegurar un aporte satisfactorio en la población. En ODIN defienden que suplementar la dieta con pastillas de Vitamina D no es una medida a largo plazo ni tampoco sostenible, ya que no toda la población se lo va poder permitir.  

Sin embargo, hasta que lo consigan, parece que la única solución es la suplementación en los meses de Noviembre a Febrero (si vivimos en España). 

He sacado esta figura de la izquierda de los datos del proyecto ODIN, concretamente de este documento. En la parte de arriba podemos ver la producción de pre-vitamina D a partir de la luz solar en Junio y en la parte de abajo en Diciembre. 

Fuentes

Las fuentes son por 100gr y las he sacado de un documento oficial publicado en Julio de 2016 "The Scientific Advisory Committee on Nutrition (SACN) recommendations on vitamin D".
  • Arenque - 16,1 mcg; 644UI
  • Salmón al vapor - 9,3 mcg; 372 UI
  • Salmón en lata - 13,4 mcg, 544 UI
  • Caballa - 8.5 mcg; 340 UI
  • Atún en lata - 1,1 mcg, 44UI
  • Huevo - 3,2 mcg; 128 UI
  • Hígado - 0,9 mcg; 36 UI
  • Cereales enriquecidos - 4,2 mcg; 168 UI.
Como veis puede ser complicado llegar a la dosis adecuada de vitamina D a partir de la solo dieta : podríamos tomar 200gr de salmón diarios, pero no es aconsejable por su contenido en mercurio, porque nuestra dieta sería aburrida y además porque desplazaríamos a otros nutrientes de la dieta.

Es decir, que parece que de momento la única solución es la suplementación, ¿y cómo suplementamos?

Existen dos suplementos disponibles: Vitamina D2 o ergocalciferool y Vitamina D3.  La mayoría de los expertos coinciden en que la vitamina D3 o colecalciferol es la mejor opción (6).

Las recomendaciones de Vitamina D para adultos rondan las 600 UI, estableciéndose su toxicidad en 10,000 UI al día durante 3 meses o 30,000 UI en un día.

Existen varios suplementos en el mercado: en herbolarios y farmacias, que rondan de las 400 UI a las 5000 UI.

Una dosis de 600 UI debería ser suficiente para mantener nuestros niveles de vitamina D en los meses de invierno - hay veces que más no significa mejor!! Si no encontráis un suplemento con una dosis baja, simplemente no lo toméis todos los días, es decir, que si el suplemento que hemos comprado tiene 1,200 UI lo podemos tomar día sí, día no. De esta manera tendríamos nuestras 600 UI.

O nos podríamos ir los meses más fríos al Caribe para recargar nuestros niveles!


References
1. Short-Term Oral Nutritional Intervention with Protein and Vitamin D Decreases Falls in Malnourished Older Adults. Floor Neelemaat, MSc, RD,*†‡ Paul Lips, MD, PhD,§‡ Judith E. Bosmans, PhD,∥‡Abel Thijs, MD, PhD,† Jaap C. Seidell, PhD,∥‡ and Marian A. E. van Bokhorst-de-van der Schueren, PhD, RD*†‡

2. Vitamin D and the risk of dementia and Alzheimer disease. Thomas J. Littlejohns, William E. Henley, Iain A. Lang, et al. Neurology 83 September 2, 2014
3. Vitamin D deficiency in Spain: a population-based cohort study.I González-Moler, S Morcillo, S Valdés, V Pérez-Valero, P Botas, E Delgado, D Hernández, G Olveira, G Rojo, C Gutierrez-Repiso, E Rubio-Martín, E Menéndez and F Soriguer. European Journal of Clinical Nutrition (2011) 65, 321–328; doi:10.1038/ejcn.2010.265; published online 22 December 2010
4. High prevalence of hypovitaminosis D in Medical Students in Gran Canaria. Canary Islands (Spain). Esther González-Padilla, Adela Soria López, Elisa González-Rodríguez, Sabrina García-Santana, Ana Mirallave-Pescador, María del Val Groba Marco, Pedro Saavedra, José Manuel Quesada Gómez, Manuel Sosa HenríquezEndocrinología y Nutrición (English Edition). Volume 58, Issue 6, 2011, Pages 267-273
5. High prevalence of vitamin D deficiency in postmenopausal women in a outpatient rheumatological clinic from Madrid area (Spain). Evaluation of two forms of vitamin D prescription. Pilar Aguado, M.a Victoria Garcés, M.a Luisa González Casaús, M.a Teresa del Campo, Patricia Richi, Juan Coya, Antonio Torrijos, Juan Gijón, Emilio Martín Mola, M.a Eugenia Martínez. Medicina Clínica. Volume 114, Issue 9, 2000, Pages 326-330.
6. Wolpowitz D, Gilchrest BA. The vitamin D questions: how much do you need and how should you get it? J Am Acad Dermatol. 2006;54:301-17.

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, 24 de febrero de 2017

Pizza de calabacín

Llevábamos un tiempo queriendo publicar esta deliciosa receta, pero no conseguíamos perfeccionarla. 

Os traemos una pizzas de calabacín, super rápidas de hacer y riquísimas. 

Ingredientes para 2:
- 2 calabacines
- 1 huevo
- Harina integral
- Mozarella light rallada

Método
  • Metemos los calabacines en un procesador de alimentos y lo picamos hasta que queden en grumos (no hagas puré!)
  • Lo metemos en el microondas durante 5 minutos para cocerlo y que pierda agua. Si no tenemos microondas, lo metemos en el horno a 200º hasta que veamos que es menos líquido.
  • En un bol, mezclamos la masa de calabacín con dos cucharadas de harina integral (del cereal que te apetezca, incluso si prefieres hacerlo con harina de garbanzos, puedes). Echamos también una cucharada de mozarella light rallado, una pizca de sal y removemos. 
  • Cogemos una bandeja de horno y la untamos un poco con aceite para que no se nos pegue nuestra masa de pizza y hacemos 4 mini pizzas.
  • Las metemos en el horno a 200º hasta que estén doradas y se pueden dar la vuelta (unos 15 minutos). Pasado este tiempo, les damos la vuelta y dejamos que se doren por el otro lado.
  • Recomendamos cortar los ingredientes y meterlos en el horno a la vez que la pizza pero en otra bandeja para que las verduras se vayan haciendo, como son ricas en agua, ahogarán un poco la masa y será menos crujiente.  
  • Cuando ya estén listas, le ponemos los ingredientes encima y lo calentamos todo en el horno.Se puedeuntar un poco de tomate natural triturado o pesto en la base (el pesto va fenomenal). 
  • Espolvoreamos un poco de mozarella light por encima y voilá! Pizza de calabacín con verduritas!

lunes, 2 de enero de 2017

Año Nuevo... Vida nueva!

Si has decidido empezar el año con un montón de buenos propósitos, ¡qué mejor que dar el primer paso cuidando tu alimentación!

Durante Enero de 2017 queremos ayudarte a cuidarte un poco más y te ofrecemos un 15% en todos nuestros paquetes.

Nuestro paquetes consisten en 5 sesiones repartidas durante 2 meses en las que te ofreceremos un asesoramiento personalizado, consejo nutricional y formación sobre etiquetado y composición de alimentos (excepto el paquete de colesterol que son 4 sesiones).

Escríbenos a info@gabinetederueda.es o llámanos al 983 08 01 49 si necesitas más información.

martes, 6 de diciembre de 2016

Posición de Eat Right sobre dietas vegetarianas y veganas

La Academia de Nutrición y Dietética americana (Eat Right) ha publicado en la edición de Diciembre 2016 de la revista Journal of the Academy of Nutrition and Dietetics un documento sobre su posición oficial en cuanto a las dietas veganas y vegetarias. Podéis acceder al documento original en inglés aquí  

Eat Right ha llegado a la conclusión, tras estudiar la evidencia disponible, de que las dietas vegetarianas y veganas (veganos no toman ningún producto animal, ni siquiera miel) son adecuadas para cualquier etapa del ciclo vital, incluidas las que generan más polémica como en el embarazo y en la alimentación de bebés y niños pequeños.

En cuanto a las proteínas, Eat Right defiende cómo mediante el consumo de legumbres y productos de soja, los vegetarianos pueden consumir un adecuado aporte de proteínas, debiendo combinarlas a lo largo del día con otros tipos de alimentos como cereales para obtener todos los aminoácidos necesarios para una nutrición adecuada. 

Admiten que vegetarianos y sobre todo veganos tienen unas concentraciones notablemente más bajas en sangre de omega 3 que los omnívoros pero que ésto no parece tener consecuencias para la salud. Los omvínivoros lo obtienen del pescado mientras que los vegetarianos y veganos lo obtienen mediante la conversión de ácido alpha linolénico ALA - en nueces, semillas - en ácido eicosapensanoico EPA y ácido docosahexanoico DHA.

Recordemos que los omega 3 son importantes para el desarollo y mantenimiento del cerebro, retina y membranas celulares y tiene un efecto positivo en el desenlace del embarazo y en la enfermedad cardiovascular y otras enfermedades crónicas. 

El hierro tampoco parace ser un problema, ya que individuos con menores depósitos de hierro como pueden ser veganos y vegetarianos, se desarrollan mecanismos adaptativos para disminuir las pérdidas de hierro y aumentar la absorción. 

El zinc, que lo encontramos en lácteos y derivados y carnes, como ciervo, cerdo, ternera, puede ser obtenido a partir de semillas, como las de calabaza o girasol o legumbres como la soja o judias. El uso de técnicas como el remojo y la germinación de judías, granos, nueces y semillas pueden aumentar la bio-disponibilidad del zinc que se encuentra unido al ácido fítico (un antinutriente que reduce su absorción).

Como las dietas vegetarianas/veganas pueden ser bajas en iodo, se recomiendo el uso de sal yodada, una recomendación de la OMS para toda la población y grupos de edad. El calcio es en mi opinión uno de los complicados. Verduras como las espinacas, que son ricas en calcio, presentan antinutrientes como fitatos y oxalatos, lo que disminuyen la absorción de calcio. Otras verduras como repollo o col rizada tienen tasas de absorción del 50%. En las bebidas vegetales sustitutivas de la leche también hay que fijarse de que estén enriquecidas con calcio para asegurar una buena ingesta. Es decir, que sí que se puede tener una ingesta adecuada de calcio pero parece que hay que invertir bastante más tiempo en la planificación de la dieta. 

Vitamina B12
La vitamina B12 no se encuentra en alimentos vegetales por lo que es necesario suplementarla en dietas vegetarianas y veganas. Punto. Si sigues este tipo de dieta, aseguráte de tomar un suplemento adecuado de B12: 2000 microgramos una vez a la semana es suficiente o 10microgramos al día (1). Las cantidades son tan dispares por temas de absorción de B12, consulta (1) si quieres saber más sobre los procesos de absorción. Eat Right recomienda usar suplementos de B12 en la forma de cianoacobalamina ya que es más estable. 

Pros y contras

La dieta vegetariana/vegan parece presentar ciertas ventajas frente a la dieta omnívora. Primero en cuanto al medio ambiente: reducir el consumo de carne ayudará a reducir el cambio climático y el efecto invernadero. Eat Right nos explica que en comparación con las dietas omnívoras, las dietas vegetarianas utilizan menos recursos de agua y de combustibles fósiles, cantidades más bajas de plaguicidas y fertilizantes. Para producir 1 kg de proteína a partir de judías se requiere 18 veces menos tierra, 10 veces menos agua, 9 veces menos combustibles, 12 veces menos fertilizantes y 10 veces menos pesticidaes que para producir 1kg de proteína a partir de ternera. 

Los vegetarianos y veganos parecen tener un índice de masa corporal menor que los omnívoros, y parece que la dieta vegetariana está asociada a un menor riesgo de enfermedad cardiovascular: menor tensión arterial, grasa abdominal, menor inflamación, etc. También presentan menor incidencia de diabetes de tipo 2 y de cáncer, particularmente de cáncer gástrico. 

Pero...

Si no puedes permirtirte ir a un dietista especializado en nutrición vegetariana, la dieta vegetariana y vegana puede ser complicada para un individuo normal, ya que requiere un cierto conocimiento de nutrición y procesos de absorción y además require bastante planificación. Planificar esta dieta para evitar deficiencias requiere tiempo, lujo que muchos no se pueden permitir. Aunque una dieta omnívora adecuada también requiere cierta planificación, no es tanta como para las dietas vegetarianas/veganas. 

Para los que no les guste tomar pastillas o suplementos, esta dieta es imposible. No suplementar con vitamina B12 ocasiona anemia perniciosa, que a largo plazo termina ocasionando daños neurológicos y depresión.  

Dicho esto, reducir la cantidad de carne que un omnívoro consume semanalmente (por ejemplo, a 1 vez o 2 a la semana) también ocasionaría un impacto positivo y no obligaría al invididuo a una planificación tan exhaustiva de la dieta ni a una suplementación. Reducir el consumo de carne roja y procesada tienen un efecto positivo en nuestra salud, así como aumentar la cantidad de verduras y hortalizas que se consume diariamente.

En conclusión, nosotros pensamos que los extremos no son la mejor opción. Si decides seguir una dieta vegetariana o vegana por razones éticas o medio ambientales, ¡fenomenal! 

Pero si es por razones de salud para prevenir ciertas enfermedades, con reducir la cantidad de productos animales que consumes diariamente y sustituirlo por fuentes vegetales y aumentar la cantidad de frutas y verduras conseguirás un efecto similar sin necesidad de planificar tu dieta tan a fondo o ponerte en riesgo de padecer deficiencias. 

Referencias