¿Y tú? ¿estás bien de la B12?

Ilustración de Paul Rogers para The New York Times

La vitamina B12, parte del complejo B, es MUY IMPORTANTE para la salud y, como casi todas las vitaminas, es necesario obtenerlas de la dieta ya que el cuerpo no las produce, o si lo hace, es en cantidades muy pequeñas.

Algunas de sus funciones:

• formación de glóbulos rojos

• memoria

• energía física, emocional y mental

• digestión adecuada, absorción de nutrientes, uso del hierro

• metabolismo de proteínas, carbohidratos y grasas

• salud del sistema nervioso: recubrimiento de nervios, conducción de impulsos nervioso

• sensación de bienestar y regulación del estado de ánimo

• concentración y claridad mental

• síntesis de ADN (material genético)

• salud cerebral

• buen funcionamiento de la tiroides

• salud reproductiva

• salud cardiovascular

¿Te das cuenta de lo esencial que es para la salud, y de todo lo que podría verse afectado si tus niveles son insuficientes o deficientes? Una deficiencia marcada de este nutriente, mantenida por algunos años, puede causar un daño cerebral irreversible (deficiencias cognitivas, Alzheimer, demencia)... Entonces a prestarle mucha atención de ahora en adelante.

Pero, ¿por qué podría generarse una deficiencia?

Dos razones básicas: porque no consumes alimentos que la contengan, o porque, a pesar de que consumes alimentos que son fuente de B12, no la absorbes bien. Aquí algunas posibilidades:

• eres vegano/a o vegetariano/a: debido a que la vitamina B12 solo se encuentra en alimentos de fuentes animales

• tienes más de 50 años: para que el cuerpo pueda absorber la vitamina B12 de la dieta es necesaria la intervención de ciertos ácidos en el estómago. La producción de estas sustancias va disminuyendo con la edad, lo que causa que la absorción de la B12 se vea afectada

• has sido diagnosticado/a con anemia perniciosa

• tomas algún medicamento para la acidez o gastritis (p. ej, omeprazol o ranitidina, etc.)

• tomas algún medicamento para la diabetes o resistencia a la insulina (metformina)

• bebes más de 4 cafés al día

• eres usuario cotidiano de alcohol

• has sido sometido/a a una cirugía bariátrica

• has tenido una infección por H. pylori

• tienes alguna enfermedad intestinal inflamatoria (enfermedad de Crohn, colitis ulcerativa), o eres celíaco/a

De esta lista te podrás dar cuenta de que inclusive comiendo una cantidad adecuada (o hasta un exceso!) de proteína animal NO estará garantizado que tus niveles de B12 sean saludables, ya que podrías no estar absorbiéndola correctamente...

Yo recomiendo, en condiciones normales, revisar tus niveles una vez al año. Lo deseable sería estar en la media del rango del laboratorio, por ejemplo, 600 pg/mL. No recomiendo estar hacia el límite inferior del rango "normal", sobre todo con síntomas neurológicos asociados. Inclusive en ciertos círculos se discute la idoneidad de los rangos de laboratorio considerados como "normales". Es posible que éstos debieran incrementarse, como en Japón, donde lo que se considera "normal" para valores de B12 está por encima de casi todo el resto de países.

Es importante notar que la deficiencia no siempre da síntomas....o, por el contrario, que alguien tenga sus valores en la parte inferior del rango "normal" y presente síntomas, los cuales desaparecen con la suplementación.

Inclusive a veces algunos de los síntomas que se atribuyen al proceso "normal" de envejecimiento (pérdida de memoria, caídas en la capacidad cognitiva, movilidad más restringida, etc.) pueden, en parte, perfectamente deberse a deficiencias en B12 (y mejorar con la suplementación!). O que te digan que estás deprimido/a y te receten un antidepresivo....cuando lo único que tienes es la B12 baja....O sea, ¡hay que estar atentos! Y si no te piden la prueba en tu control médico, solicitarla.

No está de más mencionar nuevamente que la vitamina B12 solo se encuentra en ALIMENTOS DE ORIGEN ANIMAL. Los veganos y vegetarianos tienen un riesgo alto de ser deficientes. Y si bien algunos están conscientes de este riesgo, otros piensan que si consumen algas y alimentos vegetales, están cubiertos. Sin embargo, debo decirles que no. Lo que contienen estos alimentos son "análogos" de B12 (una "B12 falsa"), es decir algo "semejante" a la B12 verdadera. Estos análogos de B12 (B12 falsa) interactúan con los receptores de la verdadera B12 en el cuerpo, bloqueando su ingreso, y terminan generando una necesidad aún mayor de la verdadera B12. Es muy importante hacer un dosaje periódico de B12 si has optado por evitar todos los alimentos de origen animal. No es algo para dejar pasar y el ignorarlo puede tener consecuencias serias.

Los estudios demuestran consistentemente que hasta el 50% de vegetarianos de larga data y el 80% de veganos son deficientes en B12. Y es absolutamente crucial descartar esta deficiencia en niños alimentados de esta manera, ya que puede afectar el razonamiento, la capacidad de resolver problemas complejos, la habilidad de pensamiento abstracto, y la capacidad de aprender. No es algo para "pasar por agua tibia"...

Dato curioso: si bien la B12 se encuentra en alimentos animales, los animales no "producen" B12....lo hacen las bacterias! Tanto en el humano como en animales, la B12 es sintetizada por bacterias en el intestino, pero el humano no puede absorber esta B12, ya que la produce en el colon (y la absorción de esta vitamina se da antes, en el intestino delgado). Los rumiantes (vacas, ovejas) sí la logran absorber. Las heces (!!) son una fuente rica de vitamina B12, y algunas especies, incluyendo perros y gatos, comen heces....alguna sabiduría ahí! (no lo estoy sugiriendo...).

Aquí les doy un listado de alimentos fuente de vitamina B12:

• hígado (res, pollo)

• sardinas

• salmón

• atún

• bacalao

• cordero

• conchitas

• carnes rojas

• almejas, ostras, choros

• leche, yogurt natural

• huevos

• pollo

Obviamente será mejor si las fuentes son orgánicas, y/o de animales que pastan. ¡No es necesario comer porciones grandes! Tampoco recomiendo cocinar a temperaturas muy altas, ya que se podría afectar el contenido de B12 en los alimentos.

Para pensarlo...

Fuentes:

https://chriskresser.com/b12-deficiency-a-silent-epidemic-with-serious-consequences/ | http://draxe.com/vitamin-b12-deficiency-symptoms/ | https://articulos.mercola.com/sitios/articulos/archivo/2016/11/28/deficiencia-de-vitamina-b12-y-los-mejores-beneficios.aspx | http://veganhealth.org/articles/everyveganspanish

B12 is just one important piece in a complex relationship between our nutrition and our bodies. Understanding how nutrients affect the body can help people make changes that improve their health, but not everyone has the time, energy, or focus to do this. Many of us could benefit from someone who understands the relationship between nutrition and health and can help us use this information to take the right steps to improve our health. Health coaches provide exactly this kind of support. Have you wanted to understand more about nutrition, exercise, and lifestyle and how they affect your health? Are you interested in learning about Functional Medicine and ancestral health? Do you want to help people make behavior changes that improve their health? If you’re answering yes to these questions, becoming an ADAPT-Certified Functional Health Coach may be right for you. Find out more about the ADAPT Health Coach Training Program. The ADAPT Health Coach Training Program is an Approved Health and Wellness Coach Training & Education Program by the National Board for Health and Wellness Coaching (NBHWC).

Why Is It Underdiagnosed?

B12 deficiency is significantly underdiagnosed for two reasons. First, it’s not routinely tested by most physicians. Second, the low end of the laboratory reference range is too low.

This is why most studies underestimate true levels of deficiency. Many deficient people have so-called “normal” levels of B12.

Yet, it is well-established in the scientific literature that people with B12 levels between 200 pg/mL and 350 pg/mL—levels considered “normal” in the U.S.—have clear vitamin deficiency symptoms. (2) Experts who specialize in the diagnosis and treatment of a deficiency, like Sally Pacholok, R.N., and Jeffrey Stuart, D.O., suggest treating all patients that are symptomatic and have B12 levels less than 450 pg/mL. (3) They also recommend treating patients who show normal B12 levels but also have elevated urinary methylmalonic acid (MMA), homocysteine, or holotranscobalamin, which are other markers of a deficiency in vitamin B12.

B12 deficiency can mimic the signs of Alzheimer’s, dementia, multiple sclerosis, and several mental illnesses. Find out what this vitamin does and learn how to treat a deficiency. #B12 #B12deficiency #cognitivedecline

In Japan and Europe, the lower limit for B12 is between 500 and 550 pg/mL. Those levels are associated with psychological and behavioral symptoms, such as:

• Cognitive decline

• Dementia

• Memory loss (4)

Some experts have speculated that the acceptance of higher levels as normal in Japan and the willingness to treat levels considered “normal” in the U.S. explain the low rates of Alzheimer’s and dementia in that country.

What Is Vitamin B12 and Why Do You Need It?

Vitamin B12 works together with folate in the synthesis of DNA and red blood cells. It’s also involved in the production of the myelin sheath around the nerves and the conduction of nerve impulses. You can think of the brain and the nervous system as a big tangle of wires. Myelin is the insulation that protects those wires and helps them to conduct messages.

Severe B12 deficiency in conditions like pernicious anemia (an autoimmune condition where the body destroys intrinsic factor, a protein necessary for the absorption of the vitamin) used to be fatal until scientists figured out death could be prevented by feeding patients raw liver, which contains high amounts of B12. But anemia is the final stage of a deficiency. Long before anemia sets in, deficient patients will experience several other problems, including fatigue, lethargy, weakness, memory loss, and neurological and psychiatric problems.

The Stages of a Deficiency

B12 deficiency occurs in four stages, beginning with declining blood levels of the vitamin (stage I), progressing to low cellular concentrations of the vitamin (stage II), an increased blood level of homocysteine and a decreased rate of DNA synthesis (stage III), and finally, macrocytic anemia (stage IV). (5)

Common B12 Deficiency Symptoms

The signs can look like the symptoms of several other serious disorders, and the neurological effects of low B12 can be especially troubling.

Here are some of the most common vitamin B12 deficiency symptoms:

• Tingling or numbness in the hands and feet

• Brain fog, confusion, and memory problems

• Depression

• Premature aging

• Cognitive decline

• Anemia

• Weakness

• Fatigue

• Reduced appetite and weight loss

• Constipation

• Trouble balancing (6)

Children can also show symptoms, including developmental issues and learning disabilities, if their B12 levels are too low.

Why Is It So Common?

The absorption of B12 is complex and involves several steps—any of which can go wrong. Any of the following can cause B12 malabsorption:

• Intestinal dysbiosis

• Leaky gut and gut inflammation

• Atrophic gastritis or hypochlorhydria, or low stomach acid

• Pernicious anemia

• Medications, especially proton pump inhibitors (PPIs) and other acid-suppressing drugs

• Alcohol

• Exposure to nitrous oxide, during either surgery or recreational use

This explains why a deficiency can occur even in people eating large amounts of B12-containing animal products. In fact, many of my patients that are B12 deficient are following a Paleo diet where they eat meat two or three times daily.

Who Is at Risk for a Deficiency?

In general, the following groups are at greatest risk for a deficiency:

• Vegetarians and vegans

• People aged 60 or over

• People who regularly use PPIs or acid-suppressing drugs

• People on diabetes drugs like metformin

• People with Crohn’s disease, ulcerative colitis, celiac, or IBS

• Women with a history of infertility and miscarriage

Note to Vegetarians and Vegans: B12 Is Found Only in Animal Products

You cannot get B12 from plant-based sources. This vitamin is only found in animal products. That’s why vegetarians and vegans need to know the signs of deficiency—and the steps necessary to fix the problem.

B12 is the only vitamin that contains a trace element (cobalt), which is why it’s called cobalamin. Cobalamin is produced in the gut of animals. It’s the only vitamin we can’t obtain from plants or sunlight. Plants don’t need B12, so they don’t store it.

A common myth among vegetarians and vegans is that it’s possible to get B12 from plant sources like:

• Fermented soy

• Spirulina

• Brewers yeast

However, plant foods said to contain B12 actually contain B12 analogs called cobamides that block the intake of and increase the need for true B12. (7) That explains why studies consistently demonstrate that up to 50 percent of long-term vegetarians and 80 percent of vegans are deficient in B12. (8, 9)

Seaweed is another commonly cited plant source of B12, but this idea is controversial. Research indicates that there may be important differences in dried versus raw purple nori; namely, raw nori may be a good source of B12, while dried nori may not be. One study indicated that the drying process used for seaweed creates B12 analogs, making it a poor source of the vitamin, while animal research suggests that dried nori can correct a B12 deficiency. (10, 11) Seaweed may provide B12, but it’s not clear if those benefits are negated when that seaweed is dried. I recommend caution for that reason.

The Impact of a Deficiency on Children

The effects of B12 deficiency on kids are especially alarming. Studies have shown that kids raised until age six on a vegan diet are still B12 deficient even years after they start eating at least some animal products. In one study, the researchers found an association between a child’s B12 status and their performance on testing measuring:

• Spatial ability

• Fluid intelligence

• Short-term memory

Researchers found that formerly vegan children scored lower than their omnivorous counterparts in each area. (12)

The deficit in fluid intelligence is particularly troubling, the researchers said, because this area impacts a child’s ability to reason, work through complex problems, learn, and engage in abstract thinking. Defects in any of these areas could have long-term consequences for kids.

I recognize that there are many reasons why people choose to eat the way they do, and I respect people’s right to make their own choices. I also know that, like all parents, vegetarians and vegans want the best for their children. This is why it’s absolutely crucial for those that abstain from animal products to understand that there are no plant sources of B12 and that all vegans and most vegetarians should supplement with B12.

This is especially important for vegetarian or vegan children or pregnant women, whose need for B12 is even greater. If you’re not willing to take a dietary supplement, it may be time to think twice about your vegetarian or vegan diet.

How to Treat a Deficiency

One of the greatest tragedies of the B12 epidemic is that diagnosis and treatment are relatively easy and cheap—especially when compared to the treatment patients will need if they’re in a late stage of deficiency. A B12 test can be performed by any laboratory, and it should be covered by insurance. If you don’t have insurance, you can order it yourself from a lab like DirectLabs.com.

As always, adequate treatment depends on the underlying mechanism causing the problem. People with pernicious anemia or inflammatory gut disorders like Crohn’s disease are likely to have impaired absorption for their entire lives and will likely require B12 injections or high-dose oral cobalamin indefinitely. This may also be true for those with a severe deficiency that’s causing neurological symptoms.

Typically in the past, most B12 experts recommended injections over high-dose oral cobalamin for people with pernicious anemia and an advanced deficiency involving neurological symptoms. However, recent studies have suggested that high-dose oral or nasal administration may be as effective as injections for those with B12 malabsorption problems. (13, 14)

Try Supplementing

Cyanocobalamin is the most frequently used form of B12 supplementation in the U.S. But recent evidence suggests that hydroxocobalamin (frequently used in Europe) is superior to cyanocobalamin, and methylcobalamin may be superior to both—especially for neurological disease.

Japanese studies indicate that methylcobalamin is even more effective in treating neurological symptoms and that it may be better absorbed because it bypasses several potential problems in the B12 absorption cycle. (15, 16) On top of that, methylcobalamin provides the body with methyl groups that play a role in various biological processes important to overall health.

Change Your Diet

Nourishing your body through whole food is the best way to get the vitamins and nutrients you need. If you’re low on B12, try eating some vitamin-rich foods like:

• Liver

• Shellfish

• Clams

• Oysters

• Organ Meats

Eating other kinds of seafood, like octopus, fish eggs, lobster, and crab, can also help you attain normal B12 levels. If you’re seafood-averse, you can also get this vitamin from:

• Lamb

• Beef

• Eggs

• Cheese

It’s important to note, though, that the amount of B12 in these foods is nowhere near as high as the levels in shellfish and organ meats.

What to Do if You’re Experiencing Vitamin B12 Deficiency Symptoms

If you suspect you have a deficiency, the first step is to get tested. You need an accurate baseline to work from.

If you are B12 deficient, the next step is to identify the mechanism causing the deficiency. You’ll probably need help from a medical practitioner for this part. Once the mechanism is identified, the appropriate form (injection, oral, sublingual, or nasal) of supplementation, the dose, and the length of treatment can be selected.

So, next time you or someone you know is “having a senior moment,” remember: It might not be “just aging.” It could be B12 deficiency.