Por Mercedes Gómez

Bajar de peso? Iniciar una rutina de ejercicio? Para muchos esto es una pesadilla y se ha convertido en un camino sin salida.

Para jóvenes y adultos que acuden a gimnasios ya existe una manera de evaluar su evolución y para aquellos que inician un régimen alimenticio (con o sin la guía de un médico o nutriologo) y combaten la obesidad deben evaluar de la misma manera su evolución para saber si el abordaje es el adecuado. Esto se logra por medio un Análisis de Composición corporal por Impedancia Bioelectrica.

La obesidad ha sido una puerta abierta a la charlatanería, productos milagro y mercadotecnia de clínicas que prometen bajar de peso en dos semanas. A quien hacerle caso? instructores de gimnasios, revistas, programas de radio y televisión atacan el problema con diferentes opiniones, lo cual crea confusión y falta de confienza. Lo mas importante es elegir a un médico o nutriologo que sea especialista en tratamiento integral de la obesidad. En ocasiones la obesidad es causada por patologías que hay que tratar primero, por mencionar un ejemplo, Hipotiroidismo.  Hoy en día tenemos herramientas diagnosticas que permiten abordar al paciente con problemas de obesidad desde otra perspectiva. Es importante que el problema sea abordado por un médico especialista en Nutrición clínica, o un médico que tenga conocimientos en terapia farmacológica de la obesidad, ya que existen indicaciones estrictas para su uso.

En este articulo les explico cada rubro de un análisis de composición corporal completo y con ello genenrar consciencia de la importancia del mismo en diferentes áreas y sobre todo en el abordaje del paciente obeso.

Lo primero es entender que un individuo sano debe ingerir menos calorías de la cantidad que gasta. En un análisis de composición corporal podemos saber cuanta energía gasta cada individuo y con base en eso podemos dar un mejor tratamiento y abordar el problema con conocimiento. En este caso se muestra un análisis de un individuo que gasta 1449 calorías al día.

El examen de composición corporal por impedancia bioeléctrica es un análisis útil no solo para el área Médica, si no tambien para la evaluación de atletas, físico culturistas, deportistas en general y cualquier individuo que este llevando una dieta. Antes de explicar el como funciona la Impedancia Bioelectrica es necesario presentar una hoja de resultados de uno de los aparatos de composición corporal mas avanzados, X scan plus II y explicar cada rubro para poder entender el por que es tan útil.

En la siguiente figura vemos una hoja de resultados completa:

Para poder entenderlo será necesario desglosar los resultados. Empezaremos con BODY STATUS.

La primera barra nos habla del peso en Kilogramos. Esta baara es la que debe disminuir si lo que busca el paciente es bajar de peso.

La segunda Barra se refiere al Indice de masa corporal (BMI), que no es mas que una relación entre el peso y la estatura del paciente por medio de la cual se obtiene una aproximación de tejido adiposo  (no mide el porcentaje de masa grasa). Es solo una aproximación que si bien marca estándares del estado nutricional de un individuo, tiene grandes desventajas y no podrá ser utilizado como criterio único en toma de decisiones medicas.  Un ejemplo claro de las limitantes del BMI es que no podra ser confiable en el caso de atletas o alteristas cuyo cuerpo contiene mayor masa magra y por lo tanto mayor peso. En estos pacientes se sobreestima la cantidad de grasa si se utiliza la fórmula de BMI.

BMI es un recurso para evaluar el estado nutricional de acuerdo con los valores propuestos por la Organización Mundial de la Salud: de 20 to 25 indican un peso optimo;  BMI menor de 20 sugiere que el paciente tiene baja de peso y un BMI por arriba de 25 indica que el paciente tiene sobrepeso. bmi mayor de 30 sugiere que el paciente tiene obesidad y un BMI mayor de 40 nos dice que el paciente tiene obesidad Mórbida.

La segunda barra se refiere al porcentaje de grasa y la tercera barra mide el porcentaje de músculo del organismo, la cual debe aumentar con rutinas de ejercicio enfocadas al aumento de la masa muscular.

Esta parte de los resultados en de gran utilidad, ya que nos muestra la cantidad de grasa abominal dividida en subcutánea y visceral, esta última es la que nos marca un riesgo en el desarrollo de síndrome metabólico y  diabetes, por lo tanto es la que mas nos interesa bajar.

La tercera barra arroja el valor del indice cintura cadera que es la relación que resulta de dividir el perímetro de la cintura de una persona entre el perímetro de su cadera. Los estudios indican que una relación entre cintura y cadera superior a 1.0 en varones y a 0.9 en mujeres está asociada a un aumento en la probabilidad de desarrollo de enfermedades metabólicas y cardiovasculares.

En el análisis segmental obtenemos dos cosas: la cantidad de musculo por extremidad y el indice de edema por extremidad (si es que lo hubiera). Aquí podemos observar qué porcentaje del ideal de musculo (para su edad y estatura) tiene el paciente en esa parte del cuerpo. Para las personas que se encuentran realizando ejercicio y quieren ver de manera objetiva si hay resultados en cuanto al aumento de la masa muscular, esta herramienta es ideal y es un gran incentivo para continuar el esfuerzo y la disciplina en el ejercicio.

En esta gráfica se muestra una predicción de peso en 20 años si el paciente no cambia sus hábitos alimenticios y estilo de vida. Esto es importante ya que es un estimulo para iniciar una dieta y una rutina de ejercicio el cual en adultos mayores debe ser de preferencia ejercicios de resistencia progresiva para disminuir la progresión de sarcopenia o perdida fisiológica de músculo esquelético.

No importa si tu medico o nutriologo no tiene esta tecnología, acude y obtén tus resultados para poder ver tu evolución de manera objetiva y saber si el tratamiento o dieta que llevas esta dando resultados.

Para poder obtener un análisis de composición corporal con esta tecnología manda un mail a dramercedesg@gmail.com Nutrición clínica. Manejo Integral de la obesidad, Terapia farmacológica de la obesidad.

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El Profesor Gerard Evan es el director del departamento de Bioquímica en la Universidad de Cambridge. En este artículo el profesor Evan explica por que el cáncer es un enemigo que se adapta y evoluciona.

Biology has undergone an unprecedented technical revolution in the past two decades. Despite its complexity, biological systems can now be mapped and catalogued in minute detail – we can monitor the activity of every one of our approximately 25,000 genes; identify almost every protein present in a cell; and even sequence the entire genomes of animals, plants, bacteria or cancer cells.

For cancer researchers, these technologies can appear a Godsend: cancers are extremely diverse diseases that arise through the build-up of mutations (errors) in the genes that regulate and restrain the growth, division, and movement of the cells that make up our bodies. The process is ‘Darwinian’ – in other words, the mutations occur at random over our lifetimes, and the faulty cells then either die out or survive and multiply as a result of the complex, changing and still largely mysterious selective pressures in the body.

The technical revolution of recent years has undoubtedly advanced our understanding of cancer, and is helping sustain impressive improvements in cancer survival rates, but why don’t we hear the word ‘cure’ very often when it comes to this disease? And what needs to be done so that we do?

Mapping complexity

Not surprisingly, given the haphazard and random way in which they evolve, every patient’s cancer is unique. Indeed, mapping and understanding the complexity within just one person’s cancer could occupy an entire research institute. In some ways, cancer research has reached an existential impasse – we can map and catalogue and annotate forever, but what is it about cancer that we really want to know?

For most of us, I suspect the answer is simple and pragmatic: we want to know how to cure patients.

Simple questions have the habit of exposing others that are more fundamental: in this case, “Why are cancers so difficult to cure?” Here, there are two general schools of thought.

Personalised medicine

Many would point to the disconcerting genetic diversity of cancers – an inevitable consequence of the haphazard way that they evolve. In the past, cancer therapies were applied fairly indiscriminately, but now many believe that effective therapies need to be specific and tailored to the particular genetic faults in each individual’s cancer – in other words cancer therapy needs to be ‘personalised’. With the advent of new targeted drugs (such as Herceptin for some breast cancers, Glivec for certain leukaemias, and brand new drugs like vemurafenib for some skin cancers), many hope that this may, at least one day soon, be feasible.

But simply personalising treatment so that it targets the genetic faults present in a tumour at the point of diagnosis, disregards the most fundamental reason for why cancers are difficult to eradicate forever: cancer cells adapt and evolve in response to treatment.

Because of this, even drugs that are initially very effective often have a progressively dwindling effect over time, as the biological systems that are blocked by the treatment spontaneously compensate by re-routing the cancer cells’ internal wiring, thereby restoring the cancer’s ability to grow and spread. To use an analogy, traffic hot spots in towns can cause major traffic jams, but cunning drivers will quickly find short cuts to get round the congestion.

Then, in those rare situations where cancer cells cannot take such ‘short cuts’, evolution takes over: in response to drug treatment, spontaneously arising mutant cancer cells that are resistant to the targeted drug rapidly outgrow their incapacitated siblings and the cancer comes back.

Although some patients can be successfully cured and their cancers don’t return – such as is often the case for testicular cancer and some childhood cancers – for other cancers the situation is different, as so many patients and their families are all too aware. It doesn’t matter how effective or specific a therapy is – if the system the treatment is targeting can be bypassed by compensation or evolution, that therapy will become less effective over time and eventually fail, and the cancer will return.

Evolutionary dead end

Against two such formidable adversaries as compensation and evolution what are we to do? A solution is to identify targets that are essential for the survival of cancer cells but whose inhibition cannot be bypassed by compensation or evolution. Rather than causing localized traffic jams within the city that can be circumvented by short cuts, we identify the bridge that is the only way out of town and then block that.

But do such fundamental targets exist? Can we make drugs that inhibit them? How bad might the side effects of such therapies be, given that such essential and non-redundant engines of biology are likely to serve important functions in ‘normal’ bodily processes? We don’t yet know.

A second idea is to chase each cancer down an evolutionary valley and into a dead end from which it cannot escape. We accept that localized traffic jams can be bypassed but, each time that happens, we identify the back route and then target that – and we keep doing it until there are no short cuts left. In practice, this would mean treating a patient with one targeted drug and, if their cancer returns with newly-developed resistance to this treatment, we then identify how that resistance evolved and hit the tumour with another drug directed at that resistance mechanism. The process is repeated until the cancer runs out of evolutionary headroom.

Both of these strategies will need a significant re-tooling and refocusing of our cancer research enterprise. We need to pay more attention to the inherent robustness and evolutionary ability of the targets against which our drugs are directed, and see if we can identify the essential engines of tumour maintenance.

One potential benefit of finding such fundamental engines is that they might be a common requirement of many, perhaps all, cancers: in which case a therapy targeted against them might usher in an exciting and far more affordable era of ‘impersonalised’ cancer treatment.

On the other hand, if we are going to chase tumours into extinction, we need to track the evolutionary trajectories of cancers in patients through sequential episodes of treatment and relapse. To do this, we must establish what information we need and how to get it without putting patients through repeated and onerous biopsies and procedures.

Common goal

All cancer researchers share the common goal of wanting cancer therapies that are effective and durable. But to do this we must never lose sight of the fact that cancers are just another example of evolution at work.

Cancers are blind. They are neither clever nor cunning – but humans are.

Un artículo fascinante que nos hace conscientes del significado social de los ojos y el por que cuando se trata de donar corneas después de la muerte,  los pacientes son mas renuentes a hacerlo en comparación con otros órganos.

Tomado de un reciente articulo del Jornal: Transplantation.

At the time that a patient is diagnosed as brain dead, a substantial proportion of families who give consent to heart and kidney donation specifically refuse eye donation. This in part may relate to the failure of those involved in transplantation medicine and public education to fully appreciate the different meanings attached to the body of a recently deceased person.

Medicine and science have long understood the body as a “machine.” This view has fitted with medical notions of transplantation, with donors being a source of biologic “goods.” However, even a cursory glance at the rituals surrounding death makes it apparent that there is more to a dead body than simply its biologic parts; in death, bodies continue as the physical substrate of relationships. Of all the organs, it is the eyes that are identified as the site of sentience, and there is a long tradition of visual primacy and visual symbolism in virtually all aspects of culture.

It therefore seems likely that of all the body parts, it is the eyes that are most central to social relationships. A request to donate the eyes therefore is unlikely to be heard simply in medical terms as a request to donate a “superfluous” body part for the benefit of another. That the eyes are not simply biologic provides one explanation for both the lower rates of corneal donation, compared with that of other organs, and the lack of adequate corneal donation to meet demand.

What’s interesting is that the operation to remove the cornea does no visible damage to the donor. It’s just the idea of the thing that puts people off.

Un articulo mas que habla de los beneficios del aceite de olivo. Buen articulo para empezar el año tomando medidas saludables.

ScienceDaily (Jan. 24, 2012) — Eating food fried in olive or sunflower oil is not linked to heart disease or premature death, finds a paper published in theBritish Medical Journal online (bmj.com).

The authors stress, however, that their study took place in Spain, a Mediterranean country where olive or sunflower oil is used for frying and their results would probably not be the same in another country where solid and re-used oils were used for frying.

In Western countries, frying is one of the most common methods of cooking. When food is fried it becomes more calorific because the food absorbs the fat of the oils.

While eating lots of fried food can increase some heart disease risk factors such as high blood pressure, high cholesterol and obesity, a link between fried food and heart disease has not been fully investigated.

So the authors, led by Professor Pilar Guallar-Castillón from Autonomous University of Madrid, surveyed the cooking methods of 40,757 adults aged 29 to 69 over an 11-year period. None of the participants had heart disease when the study began.

Trained interviewers asked participants about their diet and cooking methods. Fried food was defined as food for which frying was the only cooking method used. Questions were also asked about whether food was fried, battered, crumbed or sautéed.

The participants’ diet was divided into ranges of fried food consumption, the first quartile related to the lowest amount of fried food consumed and the fourth indicated the highest amount.

During the follow-up there were 606 events linked to heart disease and 1,134 deaths.

The authors conclude: “In a Mediterranean country where olive and sunflower oils are the most commonly used fats for frying, and where large amounts of fried foods are consumed both at and away from home, no association was observed between fried food consumption and the risk of coronary heart disease or death.”

In an accompanying editorial, Professor Michael Leitzmann from the University of Regensburg in Germany, says the study explodes the myth that “frying food is generally bad for the heart” but stresses that this “does not mean that frequent meals of fish and chips will have no health consequences.” He adds that specific aspects of frying food are relevant, such as the type of oil used.

Uno de los casos mas sonados en el área de las neurociencias en el 2011 es el caso de las siamesas (craneopagos) Tatiana Y Krista Hogan que comparten todo, incluso sus pensamientos. Imágenes cerebrales por medio de Resonancia Magnética (IRM) revelan una anatomía cerebral única, ya que no hay casos parecidos reportados por literatura medica hasta el momento. La IRM revea una linea tenue en la zona talamica que el Neurocirujano Douglas Cochrane ha denominado  “puente talamico” y se piensa que por medio de éste puente el tálamo de Krista esta unido al tálamo de Tatiana.

La zona que se indica con una flecha corresponde al tálamo.

Debido a esta unión se ha demostrado que que los estímulos sensoriales que una niña recibe la otra tambien la siente.

Este es un articulo publicado por el NY times es muy interesante en términos de neurofisiología.

Ibn al-Haytham , 965–1039 Iraq.  Padre del Método científico

Algunos científicos coinciden que el invento mas importante de todos los tiempos es Internet, mientras que otros sostienen que sin el método científico hubiera sido imposible llegar a tener los avances científicos con los que hoy contamos, por lo tanto el método científico, dialogo interminable entre la teoría y la experimentación es la Madre de todo invento.

 En una apología y justa deificación del método científico Roger Highfield escribe el siguiente articulo en la revista INTELLIGENT LIFE.

All great inventions rest on understanding how things work. And the greatest of all is the über-invention that has provided the insights on which other inventions depend: the modern scientific method, the realisation that we cannot grasp the way the world works by rational thought alone.

To gain meaningful insights into the scheme of things, logic has to be accompanied by asking probing questions of nature. To advance understanding, we need to devise rational conjectures and probe them to destruction through controlled tests, precise observations and clever analysis. The upshot is an unending dialogue between theory and experiment.

Unlike a traditional invention, the scientific method did not come into being at a particular time: its history is complex and stretches back long before 1833, when the term “scientist” was coined by the English polymath William Whewell. The method is not a concrete gadget like Gutenberg’s press, the computer or the Pill. Nor is it a brainwave like the non-geocentric universe, the Indo-Arab counting system or the theory of evolution. It is a fecund way of thinking on which the modern world rests. In relatively few generations, the rigorous application of the method has bootstrapped modern society through a non-linear accumulation of both knowledge and technology. Its impact on everyday life is ubiquitous and indisputable, even though a surprising number of people, including some senior politicians, have only a feeble grasp of its significance.

As one example, let’s look forward a few decades to an invention which is destined to end the energy crisis, change the global economy and curb climate change at a stroke: commercial fusion power. This invention, like nearly all others, is inconceivable without the scientific method, in this case the insights that it gives into the process by which the Sun and other stars transmute matter, transforming hydrogen into helium to release astounding amounts of energy. This invention will rest on the application of a diverse range of scientific insights, whether in the creation of reactor materials that can withstand unbelievable pummelling by subatomic particles or the design of affordable superconducting magnets that can confine plasma ten times hotter than the Sun’s core.

The scientific method has changed life, culture and everything, and set the stage for a reassessment of our place in the universe. It is the mother of all invention.

Roger Highfield is a former editor of New Scientist and science editor of theDaily Telegraph. He now works for the National Museum of Science and Industry.


Hay varios libros de ciencia para niños, tantos que sería difícil mencionar los mejores. Sin embargo son pocos los padres de familia que se dan a la tarea de leer con los niños un libro de ciencia, aprender con ellos, Crear o hacer experimentos y fomentar el amor por la ciencia y la naturaleza.

Con la evolución científica y tecnológica es necesario el introducir a los niños a este mundo y promover el ejercicio de las ciencias.

Tome un articulo de Janet D. Stemwedel de la revista Scientific American en el cual la autora recomienda algunos libros de ciencia para niños. Me parece un buen articulo a explorar para elegir un libro y compartirlo con los pequeños. Tiempo, lectura, cultura y ciencia son un gran regalo para estas vacaciones.

A Drop of Blood by Paul Showers, illustrated by Edward Miller.

The text of this book is straight-ahead science for the grade school set, explaining the key components of blood (red blood cells, white blood cells, platelets) and what they do. There are nice diagrams of how the circulatory system gets involved in transporting nutrients as well as oxygen, pictures of a white blood cell eating a germ, and a step-by-step explanation of how a scab forms.

But this unassuming text is illustrated in classic horror movie style.

All the “people” in the drawings are either vampires or … uh, whatever those greenish hunchbacked creatures who become henchmen are. And this illustration choice is brilliant! Kids who might be squicked out by blood in real life cannot resist the scary/funny/cool cartoonish vamps accompanying the text in this book. The drawing of the Count offering Igor a Band-aid for his boo-boo is heart-warming.

Read an archived conversation with a younger time-slice of my kids about blood.

* * * * *
Octopuses and Squids by Mary Jo Rhodes and David Hall. Photographs by David Hall.

Seahorses and Sea Dragons by Mary Jo Rhodes and David Hall. Photographs by David Hall.

We love books with chapters, lots of photographs, and glossaries. What can I say?

These two books pair with each other nicely, evaluating the relative merits of syngnathids and cephalopods is kind of like weighing whether you’d rather be able to fly or to become invisible. Is it better to have leafy bits on your body the better to hide in seaweed, or to be able to change color and shape to camouflage? (What if you got distracted and forgot to do it?) To keep your fertilized eggs in a cave, or to have the father incubate them in his brood pouch? To enjoy solitude in your corner of the ocean, or to be social?

Read an archived conversation with a younger time-slice of my kids about these choices.

* * * * *
How a Seed Grows by Helene J. Jordan. Illustrated by Loretta Krupinski.

This is a nifty science book for little kids. Our favorite thing about this book is that it’s all about getting empirical.

After some unassuming storybook text (with lovely illustrations) about different kinds of seeds and the different kinds of plants that grow from them, the book gets down to business and lays out an experiment for the young reader to do: Plant a dozen bean seeds and see what happens to them over time.

After planting the seeds, each in its own eggshell or other container, and watering them daily, on day 3 you dig up the first seed and examine it it. Two days later, you dig up the second seed and see what’s happening. Every few days you dig up another seed so you can observe the roots growing and developing root hairs. Once the shoots start pushing out of the soil in the containers with the not-yet excavated seeds, the kids can examine the growth of the plants without digging them up. At this point, if the kids are still interested, they can plant the bean seedlings in the ground.

The charm of this book is not just that it lays out a hands-on experiment for kids to do. It also makes it clear to the kids that there is likely to be some variation in what is observed — not only might your bean seeds grow more quickly or more slowly than the day-by-day development illustrated in the book, but that your 12 beans of the same kind might develop at different rates, even if you do your best to plant them and water them just the same. As well, the idea of sacrificing growing seeds to learn something is presented in a way that kids can handle. (If a book doesn’t give you permission, sometimes kids are a little too precious with the seeds they have planted.)

This is a fun way to get your hands dirty.

* * * * *
The Periodic Table: Elements with Style, written by Adrian Dingle, illustrated by Simon Basher. (Boston: Kingfisher, 2007)

The book introduces several representative elements from the periodic table. For each element, there’s a listing of crucial information like the element’s symbol, atomic number, atomic weight, color, standard state, density, melting point, boiling point, and data of discovery. But the real story is the first person introduction to each element’s character, tendencies, and common uses. Hydrogen says, “I am the simplest and lightest of all the elements, the most abundant in the universe, and the source of everything in it — from matter and energy to life.” Cesium pipes up, “Soft and golden, I’m way more exciting than gold.” Magnesium chirps, “I’m happy to mix in any social gathering of the elements, making friends with anyone.” Iron hollers, “I am at the center of everything.”
Clearly, there are a lot of strong personalities here.

For all the elements that appear in this book (except hydrogen), the introductions to the elements are preceded by a discussion of the group they run with — the alkali metals, the halogens, the carbon elements, and so on. The book offers a description for each of the groups in the periodic table, including the lanthanides and actinides and the transactinides (although given their instability, we don’t get to meet individuals from the latter group). The group descriptions are a little less gripping than the portraits of the elements in each group, but they do a nice job conveying which groups have elements that seems to copy each other closely and which of these periodic table cliques seem to tolerate more individualism.

Each element also has a portrait, a bold graphic that conveys some visual clue to the element’s temperament of common uses.

Of course, the book includes these portraits in periodic table layout, too. And the book includes an index and a glossary.

As a casual read, this is not a book that will leave a kid with exhaustive knowledge about all the chemical elements. However, the “personal information” about these elements comes across as quirky and compelling, and it’s hard for the young reader to resist forming some opinions about which elements he or she would like to hang out with.

Read an archived conversation with a younger time-slice of my kids about this book.

* * * * *
Big Tracks, Little Tracks: Following Animal Prints by Millicent E. Selsam, illustrated by Marlene Hill Donnelly.

This book helps kids to become “nature detectives” by getting them to look at different kinds of animal tracks for clues about the animals that left them. The presentation is pretty Socratic: What do we see in the prints? What do we know about how this animal or that animal moves about?

The approach of inferring what happened from clues is fun. There are some facts that are kind of cool to learn (e.g., seagulls run into the wind to take off, so you can tell by the direction of their footprints what direction the wind was blowing when they launched). But the ick factor for this book is pretty low. (There is a trangressive moment where cats and dogs switch places, but it’s not gross.)

Along the same lines, but harnessing the magnetic power of the gross:

Who Pooped in the Park? Great Smoky Mountains National Park by Steve Kemp, illustrated by Robert Rath.

Like Big Tracks, Little Tracks, this book gets kids interested in the inferences they can draw from their observations. However, it beats out Big Tracks, Little Tracks for the simple reason that poop (as a charter member of the Pantheon of Gross Things) is absolutely hilarious.

In fact, scat is only the bait that attracts kids (like flies, if you will) to learn about the other clues animals leave in the National Park: tracks, nibbled twigs and scraped tree bark, rocks that have been moved. This book doesn’t just talk about the particular animals that inhabit Great Smoky Mountains National Park, but it describes some of the ways they interact with each other in the ecosystem. (For example, the non-native wild hogs eat up the native salamanders.) Scattered through the book are “The Straight Poop” boxes of related facts (e.g., that rabbits eat their own scat to maximize the nutrition they get out of their food by digesting it twice).

My kids loved this book, and it gave them something intelligent to say about animal droppings we came upon in family hikes — at least, once they were done giggling.

There are versions of this book available for many other National Parks, each of which deals with the particular fauna that inhabits (and poops in) the particular park.

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