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New Research Underscores B-12’s Vital Role in Brain Preservation

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The latest research finds vitamin B-12 deficiency is the ‘canary in the coalmine’ when it comes to mental fog, explains nutrition expert Joseph Mercola, MD. It’s a silent problem that affects millions, and it is easy to miss.

This primer on the effects and causes of low B-12 is excerpted with kind permission from Dr. Mercola’s educational website ( It was first published Apr 5, 2012. See footnote* for links to much more.


The Vitamin You Need for a Sharp Brain (Yet 1 in 4 are Deficient)

Vitamin B-12, or rather a lack thereof, has been called the “canary in the coalmine” for your future brain health, and recent research has bolstered the importance of this vitamin in keeping your mind sharp as you age.

According to the latest research, people with high levels of markers for vitamin B-12 deficiency were more likely to score lower on cognitive tests, as well as have a smaller total brain volume, which suggests a lack of the vitamin may lead to brain shrinkage.

This issue is of paramount importance for many of you reading this for two reasons:

1. Vitamin B-12 deficiency is very widespread.

2. Your blood level of vitamin B-12 is not an adequate marker of whether or not you’re deficient, making vitamin B-12 deficiency easy to miss.

What is Vitamin B-12?

Vitamin B-12 is a powerhouse micronutrient often known as the “energy vitamin” because it assists in energy production. Your body relies on the efficient conversion of carbohydrates to glucose – your body’s source of fuel – to run smoothly, and vitamin B-12 plays a major role in that conversion. B-12 also enables your body to convert fatty acids into energy.

Further, your B-12 level impacts a number of very important functions in your body, including:

– Carbohydrate and fat metabolism    – Help with regulation of the formation of
                                                        red blood cells

– Healthy nervous system function     – Promotion of normal nerve growth and

– Cell formation and longevity             – Support of female reproductive health
                                                         and pregnancy

– Proper circulation                             – Feelings of well-being and mood

– Adrenal hormone production            – Mental clarity, concentration, memory

– Healthy immune system function     – Physical, emotional and mental energy

Problems with Memory & Brain Function –
Two Top Signs of Vitamin B-12 Deficiency

Mental fogginess and problems with memory are two of the top warning signs that you have vitamin B-12 deficiency, and this is indicative of its importance for your brain health.

• In addition to the latest Neurology study at Rush University, which found more signs of shrinkage of brain tissue among those with low vitamin B-12 [further research there, published in PLoS One, finds that even “subclinical” cobalamin (B-12) deficiency may be related to cognitive decline in older adults],

• A Finnish study published in Neurology last year found that people who consume foods rich in B-12 may reduce their risk of Alzheimer’s in their later years. For each unit increase in the marker of vitamin B-12 (holotranscobalamin), the risk of developing Alzheimer’s was reduced by 2%.

• Research also shows that supplementing with B vitamins, including B-12, helps to slow brain atrophy in elderly people with mild cognitive impairment (brain atrophy is a well-established characteristic of Alzheimer’s disease).

What Causes B-12 Deficiency?

Vitamin B-12 is the largest vitamin that we know of. Because of its large size, it is not easily absorbed passively [via the digestive system] like most supplements. Because of this, many, if not most oral B-12 supplements are worthless and do not work.

Vitamin B-12 requires a complex system in your body involving intrinsic factor to bind to it so it can be actively absorbed in the end of your small intestine (terminal ileum). As you grow older the ability to produce intrinsic factor decreases and causes a deficiency state.

Studies from the U.S. Framingham trial show one in four adults are deficient in vitamin B-12, and nearly half the population has suboptimal blood levels. If you eat an all vegetarian or vegan diet, vitamin B-12 is one of the nutrients your body is most likely deficient in, as it is naturally present in foods that come from animals, including meat, fish, eggs, milk and milk products.

However, there are many other causes of B-12 deficiency as well, including:

Food-Cobalamin Malabsorption Syndrome
This condition results when your stomach lining loses its ability to produce intrinsic factor, a protein that binds to vitamin B-12 and allows your body to absorb it into your bloodstream at the furthest point of your small intestine.

• Intrinsic factor is a protein made by your stomach.

• It grabs onto the B-12 molecule, and together they move through your stomach to your small intestine.

• When they reach the end of your small intestine, the intrinsic factor is absorbed first, pulling the B-12 with it into the cells of your large intestine, where they are absorbed for use by the rest of your body.

Increasing Age
Intrinsic factor diminishes as you age, and this means it’s virtually impossible to get B-12 from your diet. This also means the older you get, the more likely you will need to supplement B-12.

Use of the Drug Metformin for Type 2 Diabetes
Use of metformin (brand names include Glucophage, Glucophage XR, Fortamet, Riomet, and Glumetza) may inhibit your B-12 absorption, especially at higher doses.

Coffee Consumption
Four or more cups of coffee a day can reduce your B vitamin stores by as much as 15%.

Use of Antacids
The use of antacids or anti-ulcer drugs will lower your stomach acid secretion and decrease your ability to absorb vitamin B-12. Stomach acid (hydrochloric acid) is a crucial ingredient in your body’s ability to absorb B-12. If you’re taking a medication specifically designed to reduce the amount of stomach acid you produce, your body’s ability to use vitamin B-12 from the food you eat or the supplements you take will be significantly compromised.

Gastric Bypass Surgery

Exposure to Nitrous Oxide (Laughing Gas)

Helicobacter pylori Infection (see sidebar, attached)

Why a Blood Test May Not be Enough to Detect Deficiency

Blood tests for vitamin B-12 deficiency aren’t as clear cut or helpful as they are for other nutritional deficiencies. Standard tests to assess vitamin B-12 concentrations are limited because the clinical severity of vitamin B-12 deficiency is unrelated to vitamin B-12 concentrations. As researchers concluded in Neurology:

Concentrations of all vitamin B12-related markers, but not serum vitamin B-12 itself, were associated with global cognitive function and with total brain volume.”

So generally speaking, you can use the following recommendations to screen for vitamin B-12 deficiency:

• If your vitamin B-12 concentration is less than 150 pmol/L, you are considered B-12 deficient, and you and your health care practitioner should take steps to determine the underlying cause(s) and treatment

• If your B-12 concentration is between 150 and 200 pmol/L, your serum MMA (Methylmalonic Acid) level should be determined to identify whether your situation requires more investigation and treatment. Research suggests elevated levels of MMA (a natural compound found in your body) are an indicator for vitamin B-12 deficiency.

However, if you suspect or are concerned you are vitamin B-12 deficient, a more practical option may be to simply supplement your diet with B-12 and see if your symptoms improve.

B-12 is available in its natural form only in animal food sources. These include seafood, beef, chicken, pork, milk, eggs.

If you don’t consume enough of these animal products (and I don’t recommend consuming seafood unless you know it is from a pure water source) to get an adequate supply of B-12, or if your body’s ability to absorb the vitamin from food is compromised, vitamin B-12 supplementation is completely non-toxic and inexpensive, especially when compared to the cost of laboratory testing.

In fact, the first treatment most doctors and other health care experts will suggest upon receiving B-12 deficiency lab test results is supplementation with vitamin B-12. I recommend an under-the-tongue delivery mode [spray or tablet formulated to pass through this very thin mucous membrane], as this technology helps you absorb it into the fine capillaries under your tongue.

This delivery system bypasses the intrinsic factor problem and is much easier, safer and less painful than having your doctor inject you with a vitamin B-12 shot.

Signs and Symptoms to Watch For

Besides the above-mentioned mental fogginess and memory problems, there are actually a wide range of symptoms of vitamin B-12 deficiency, from mild to severe, which can affect your body, mind and mood.

In general, the signs are:

• Fatigue, lack of energy, muscle weakness, tingling in your extremities

• Mental fogginess or problems with your memory, trouble sleeping

• Mood swings, especially feelings of apathy or lack of motivation.

Other symptoms of long-term, chronic B-12 deficiency are:

• Depression

• Dementia and Alzheimer’s

• Anemia [reduced number of red blood cells]

• Neurological and neuropsychiatric conditions

• Female fertility and childbearing problems

• Heart disease and cancer.

Even though vitamin B-12 is water-soluble, it doesn’t exit your body quickly like other water-soluble vitamins.

• B-12 is stored in your liver, kidneys and other body tissues,

• And as a result, a deficiency may not show itself for a number of years until you finally run out of this naturally stored internal source of the vitamin.

This time lag in seeing symptoms of a B-12 deficiency is a serious concern, because after about seven years of deficiency, irreversible brain damage can potentially result.

So if you are suffering from any of the symptoms above, it makes sense to take steps to increase your levels to protect your long-term brain, and overall, health.

IMPORTANT B-12 Summary: Please Remember…

If you believe you need a vitamin B-12 supplement, don’t hesitate to take one. They are very safe and there are virtually no known side effects.

However, avoid oral [swallowed] B-12 supplements, as they will not be easily absorbed. You can take an injection or choose a far easier sublingual (under your tongue) formulation that allows the large B-12 structure to bypass your intestine and be absorbed directly into your blood stream, allowing you to benefit immediately.


Helicobacter pylori Infection: May Be Another Cause of B-12 Deficiency

According to Dr. Mercola’s article on H. pylori and B-12 deficiency – “Is This Causing Your Chronic Cough?” (first published Mar 12, 2011):

H. pylori bacteria, the actual cause of most cases of peptic ulcers and GERD in America, may be associated with vitamin B-12 deficiency… Studies have shown that removal of the H. pylori bacteria from the stomach increases absorption of B-12. This bacteria appears to interfere with your stomach’s parietal cell’s production of intrinsic factor, which is essential to getting the B-12 your body needs out of the foods you eat…

In one study, 56% of patients suffering from pernicious anemia (extreme B-12 deficiency) had H. pylori bacterial infections in their stomachs. Of these people, 40% saw their B-12 levels improve with the removal of the H. pylori bacteria.

So if you suffer from a mystery cough, you may actually be suffering from a bacterial infection in your stomach that is causing both chronic deficient B-12 levels (the stomach needs normal levels of hydrochloric acid to absorb B-12 and H. pylori restricts stomach acid production) and possibly GERD-related asthma symptoms.


* Source:

Dr. Mercola is the founder of the world’s most visited natural health web site, You can learn the hazardous side effects of OTC Remedies by getting a FREE copy of his latest special report The Dangers of Over the Counter Remedies by going to his Report Page.

Note: This information (© 1997-2012 Dr. Joseph Mercola. All Rights Reserved) has not been reviewed by the FDA. It is general information, based on the research and opinions of Dr. Mercola unless otherwise noted, and is not meant to prevent, diagnose, treat or cure any condition, illness, or disease. It is not intended to replace a one-on-one relationship with a qualified healthcare professional and is not intended as medical advice. It is always very important that you make no change in your healthcare plan or health support regimen without researching and discussing it in collaboration with your professional healthcare team.

See also:

“The Vitamin B-12 – ME/CFS/FM Connection,” by Dana Myatt, MD.

“The Brain Boosting B-12: Hydroxocobalamin,” by Karen Lee Richards.

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