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Vitamin B12 Deficiency
the Masking Effect of Folic Acid

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What is the big deal with B12?

Vitamin B12 is essential for our health. On average, we need 2.4 micrograms a day. Our bodies need it to make red blood cells, nerves, DNA, and carry out other functions. Simply put, we cannot live without it. If left untreated, it may result in death.

Vitamin B12 Deficiency - the Masking Effect of Folic Acid

B12 deficiency - A problem of developing countries?

Most people believe that B12 deficiency is a problem of only underdeveloped countries. In the USA and other developed nations, most commonly eaten foods are fortified with vitamins and minerals. Table salt is fortified with iodine the same way as flour products are enhanced with a type of B vitamin: Folic Acid. As a result, claims of B12 deficiency are easily overlooked. A study from 2000 (Framingham Offspring Study indicated that B12 deficiency is far more widespread than formerly believed. It revealed that almost 40% of studied group of 3,000 had low values of B12. This percentage is believed to be even higher these days. If the results of the studied group are extrapolated, it means that almost two fifths of the U.S. population may be suffering from vitamin B12 deficiency. There are many more  recent publications suggesting that it has become a bigger problem over the last few years.

Animal products are the best sources of vitamin B12, so naturally you would think: let's just eat more of them! Oddly enough, the researchers found no association between B12 levels and animal products intake. According to the Framingham Offspring Study, it’s not because people aren’t eating enough meat, rather the vitamin isn’t getting absorbed. Why does this happen? There could be many reasons as highlighted further below.

This video published on 22 Jan 2013 presents cases of four misdiagnosed patients. Its aim is to raise awareness about the B12 deficiency issue:

"Vitamin B12 deficiency can sneak up on you, and can lead to a myriad of diseases and disorders. Know the signs and symptoms. You could be deficient yet still test in the so-called range of normal B12 on a blood test, especially if you have taken an oral B12 supplement of uncertain quality, or you have been under-treating the deficiency. Oral B12 supplements do not work for all patients; patients with digestive/absorption problems benefit from B12 injections, as do patients with nerve damage."

Eggs and animal products are good sources of vitamin B12

Basic Facts about B12

  • The main B12 deficiency signs and symptoms: strange sensations, numbness, or tingling in the hands, legs, or feet, difficulty walking (staggering, balance problems), weakness, fatigue, anemia, a swollen, inflamed tongue, yellowed skin (jaundice), difficulty thinking and reasoning (cognitive difficulties), or memory loss, paranoia or hallucinations, anxiety and mood swings and loss of taste and smell.

  • B12 deficiency could be also responsible for: bone injuries, cardiovascular disease, stomach and GI problems and birth defects.

  • The main risk factors for vitamin B12 deficiency are: strict vegetarian / vegan diets (especially vegan diets), pregnancy, age over 50, low stomach acid (impaired B12 absorption via diet), Celiac or Crohn’s disease, food allergies, autoimmune disorders, eating disorders and use of oral birth control pills.

When B12 is deficient, it could very easily be treated with B12 shots. Early detection and treatment is important. If left untreated, the deficiency can cause severe neurologic problems and blood diseases with no prospect of recovery.

The problem with diagnosis

The National Institute of Health has found that large amounts of Folic Acid can mask the damaging effects of vitamin B12 deficiency. This means that current blood tests may not reveal the actual level of B12. Furthermore, Folic Acid can correct anemia caused by vitamin B12 deficiency without correcting the neurological damage that also occurs.

So, it's clear that having excessive Folic Acid in our diet may hide the symptoms. But how do we get so much of Folic Acid? For a start, Folic Acid supplements are common, especially as a part of pre-natal vitamin supplements. Also, the United States legislation has required enriched flour to contain Folic Acid to reduce cases of birth defects.

To counter the masking effect of B12 deficiency the National Institute of Health recommends "Folic Acid intake from fortified food and supplements should not exceed 1,000 mcg daily in healthy adults." But how do we keep track of that? The reality is that we cannot.

Tuna is an excellent source of vitamin B12!

The best sources of vitamin B12

Let's not forget that B12 deficiency can only be treated with increased level of B12 intake. So where do we get B12 from? There is virtually none in plants. It's animal products that give us vitamin B12. Here is a list of foods rich in B12: seafood (clams, oysters, mussels, octopus, crab, lobster), fish (mackerel, salmon, tuna, cod, sardines), liver, beef, lamb, cheese and eggs.

Keep in mind, as mentioned above, not all the causes of vitamin B12 deficiency are related to nutrition. Some people have problem absorbing B12. In such cases, you will need to contact your physician.

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Martina Slajerova
Creator of

Martina Slajerova

I changed the way I ate in 2011, when I was diagnosed with Hashimoto’s, an autoimmune disease that affects the thyroid. I had no energy, and I found it more and more difficult to maintain a healthy weight.

That’s when I decided to quit sugar, grains, and processed foods, and to start following a whole-foods-based ketogenic approach to food.

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Comments (7)

I’m so glad you included this very important information. I was misdiagnosed as having Multiple Sclerosis over 20+ years. I had been suffering from more symptoms I thought weren’t related to my”MS” but from something else. My neurologist (MS specialist, told me to take tramadol for pain & flexeril for spasms) I decided to get a second opinion! Thank God I Did! My current neurologist is an expert in MS & hard to diagnose diseases. He ran every test for “MS like symptoms “! Vitamin B12 deficiency is right up there! All the symptoms such as numbness & tingling, gait difficulty, Memory loss, brain atrophy, & spinal cord thinning! Along with optic neuritis, all other symptoms of B12 deficiency are present! I’ve been anemic for years & no doctor treated it except when I needed,” blood transfusions!
When this doctor mentioned my low B12, he stated this is just slightly low BUT the medical profession hasn’t caught up to our research in this area. People need HIGHER LEVELS then the current labs indicate, (He left the NIH, to enter patient  care  few months ago. lucky for me)!
Now I’m on supplements of B12 & I’ve always been a meat eater so that wasn’t a problem, it was just too low for me! He said unfortunately this is much more common then physicians realize, as they are taught to read labs as guidelines for all!
Thank you again for bringing this to everyone’s attention! God Bless you!

I recently found out I had a B-12 deficiency, turns out it was caused from taking a popular prescription acid reducer! Kudos to my new Dr for checking my B-12 levels, none of the previous physicians have ever checked it before!!

Not that it's a problem, but my B12 is thru the roof.  No explanation as to why or what may be causing it.  All tests are clear.  I guess I should be happy that it's not the opposite lol  

megadose sublingual B12 treated my Herpes zoster ophthalmicus!!!
Just 4 days and my blisters dried and soon to fall off! Anyone knows what it's like to have that disease will swear how excruciatingly painful it is. Aside from depression, affected brain, and affected eyesight--possibility of blindness.
My physician doctor just prescribed paracetamol tramadol..and saying it will heal as time goes on! WTF! I felt a lot of pain and "PRESSURE" in the back of my left eye, and afraid of losing my left eye, and be blind. I analytically I thought that paracetamol is just for pain, but IT WILL NOT treat my progressing zoster ophthalmicus. So I researched and found an article, that in Indian research, b12 is the treatment!
This doctor also said she don’t believe in supplements, when I said I was taking megadose vit c.
Discern who to trust. Use your common sense. Because some doctors are incompetent.

I had a very bad experience with my endocrinologist and with my GP - I've changed both of them! You have to educate yourself these days and that's what I did... and it takes time to find a good doctor that knows what's going on. Sadly, many doctors still believe that saturated fat and cholesterol cause heart disease, that fat is bad for us and carbs are harmless :-/

Thank you for this article. I myself had problems with B12 deficiency (being vegetarian for more than 5 years) and nobody knew what was wrong with me. Eventually, I got the right treatment and I'm fine now. It's incredible how common this could be...

True! I'm glad you got the treatment - I know a few people who were found deficient in B12 :-( It's not as rare as people may think...