Vitamin B-12 (cobalamin) is an essential nutrient, meaning it is required for normal body functioning but cannot be produced by the body.
Therefore, it is necessary to obtain the B-12 our bodies need through the food we eat and/or dietary supplements. A vitamin B-12 deficiency is relatively common – thought to affect approximately 15% of the general population. That percentage goes much higher among people with chronic illness.
Symptoms of a Vitamin B-12 Deficiency
The symptoms of a vitamin B-12 deficiency are remarkably similar to many of the symptoms of fibromyalgia, ME/CFS, Lyme disease, multiple chemical sensitivities and Gulf War syndrome.
While a B-12 deficiency is not thought to be the cause of these illnesses, it has been implicated as a possible factor in a number of different chronic illnesses.
The symptoms of a vitamin B-12 deficiency may include:
- Fatigue, weakness
- Memory loss
- Shortness of breath
- Poor sense of balance
- Vision problems
- Diarrhea or constipation
- Loss of appetite
- Cognitive functioning problems
- Beefy, red, smooth and sore tongue
- Sore mouth and/or bleeding gums
- Numbness and tingling of hands and feet
- Loss of hearing and tinnitus
Dietary Sources of Vitamin B-12
Vitamin B-12 is produced exclusively in the digestive tracts of animals. The richest dietary sources of B-12 are beef liver and clams. Other good natural sources include meat, fish, eggs and dairy products
Are You Getting Enough B-12?
A better question might be “Are you absorbing enough B-12?”
A deficiency of vitamin B12 is not usually caused by insufficient dietary intake but rather by a lack of intrinsic factor secretion. In order for the B-12 obtained from food to be absorbed by the body, it must attach itself to a protein called intrinsic factor, which is secreted in the stomach. Without intrinsic factor, vitamin B-12 cannot be absorbed.
Unfortunately, a number of things can inhibit the secretion of intrinsic factor, which in turn blocks the absorption of B-12 and results in a vitamin B-12 deficiency. High-risk factors for poor absorption include:
- Digestive disorders such as celiac disease, Crohn’s disease, irritable bowel syndrome, bacterial overgrowth in the small intestine or a parasite.
- Gastric bypass surgery.
- Acid-reducing medications – Medications commonly prescribed for heartburn, GERD, acid reflux and peptic ulcers, such as proton pump inhibitors like Prilosec, Prevacid and Nexium, or H2 (histamine2) receptor antagonists like Pepcid and Zantac, suppress the secretion of stomach acids, also blocking the secretion of intrinsic factor.
- Diabetes medications – Drugs like Metformin, used to treat diabetes, are known to impair intestinal absorption.
- Aging – The older we get the more likely we are to be deficient in B-12.(3) The Institute of Medicine (IOM) recommends that adults over 50 supplement their diets with vitamin B-12.(4)
- Vegetarian and vegan diets – Since B-12 is only found naturally in animal foods, it is important for people on these diets to supplement their diets with B-12.
- Pernicious anemia – a blood disease that develops when the body lacks the intrinsic factor necessary to naturally absorb vitamin B12 from food.
Diagnosing a Vitamin B-12 Deficiency
A B-12 deficiency can be difficult to diagnose because serum blood levels of B-12 may test normal. Having circulating B-12 in the blood doesn’t mean it is being utilized properly by the body’s cells.
Some doctors suggest that a test measuring methyl-malonyl coenzyme A levels in the urine gives a more accurate reading of B-12’s availability in the body.
However, because there are no known toxic effects, even at extremely high dosages, often doctors will prescribe vitamin B-12 based on symptoms and risk factors, rather than testing for a deficiency.
The Four Forms of B-12 – Which Is Best?
We tend to talk about vitamin B-12 as a single entity, but there are actually four different forms of B-12 in the cobalamin family – each with its own distinct purpose.
Methylcobalamin – Promotes improved memory, focus and concentration. Is important for the central nervous system, playing a vital role in cell growth and nerve cell regeneration. Supports healthy homocysteine levels. Helps regulate circadian rhythms, which contributes to improved sleep quality and refreshment.
Adensylcobalamin (Dibencozide) – Promotes metabolism of essential fatty acids to produce more energy. Reacts with cells to provide muscles and nerves with bursts of energy.
Cyanocobalamin – The most common form of B-12 found in oral supplements and injections. Becomes active in the liver, creating enzymes to help with blood formation, cell reproduction, iron utilization, and tissue synthesis. Promotes the digestion and absorption of foods.
Hydroxocobalamin – Helps remove heavy metals from the system and supports overall detoxification. Is FDA-approved as an antidote for cyanide poisoning. Important for smokers because it removes the cyanide found in cigarette smoke. Also assists with methylation (gene regulation) and energy production.
Injections or Pills – Is There a Difference?
Vitamin B-12 can be administered either orally or by injection. Since no one wants to get a shot unless they absolutely have to, it’s important to determine whether oral tablets are as effective as injections
Two studies addressing that very issue concluded that oral supplementation with large doses of B-12 was as effective, if not more effective, than injections
When it comes to oral supplementation of B-12, sublingual tablets are the best option because they are absorbed directly into the mucous membrane, by-passing the digestion process, which is often the cause of the deficiency to begin with.