Vitamin B12 is the largest and most complex of the water soluble B vitamins and the only vitamin that contains a trace element, cobalt, which gives it a red color and the common name cobalamin. As a coenzyme, vitamin B12 plays a crucial role in the healthy functioning of the body including energy metabolism, production of DNA and RNA, brain and nervous system function, the formation of red blood cells, and proper functioning of the cardiovascular, reproductive and immune systems. Though adults need only 3 to 6 mcg of B12 per day for optimum health, dietary intake of B12 should exceed that amount due to the complex process required to assimilate and metabolize this essential nutrient. Ingested B12 that is not immediately used by the body is stored in the liver and to some degree the kidneys and other body tissues. Any excess is harmlessly passed out of the body as waste. In the absence of daily B12 intake, B12 stores can last for several months to years before deficiency becomes apparent.

The human active forms of vitamin B12 are only available from animal sources where it is produced by intestinal bacteria or supplements from cultured microorganisms. Liver has the highest content of B12 (100 mcg per 100 g), followed by kidney (55 mcg), oily fish (4-20 mcg), shellfish (4-12 mcg) white fish (0-2 mcg), red meats (1-3 mcg), white meats (0-2 mcg), eggs (2.5 mcg), and dairy products (1-1.5 mcg). Butter has only trace amounts of B12. Plant forms of vitamin B12, called B12 pseudo analogues, which are concentrated in foods such as spirulina, blue-green algae, chlorella, seaweeds, tempeh and nutritional yeast, cannot be utilized by the body. In fact, in large amounts they may interfere with metabolism of the human active forms of B12 by binding to B12 receptor sites. B12 deficiency is prevalent in vegetarians and vegans unless they take vitamin B12 supplements and even people who eat meat are often deficient in this vital nutrient. The natural human active forms of B12 are methylcobalamin (the most bioavailable form), hydroxocobalamin, and adenosylcobalamin. Cyanocobalamin is a synthetic human active form of B12 which is derived from charcoal and is commonly found in supplements. However, cyanocobalamin requires a four step process to metabolize into the active form methylcobalamin before it can be utilized by the body, during which a small amount of toxic cyanide is released. The sublingual form of methylcobalamin is the most effective oral B12 supplement since it is absorbed directly into the bloodstream through the mucosal lining of the mouth. B12 transdermal patches are another alternative. Vitamin B12 can also be delivered directly into the bloodstream by injection.

B12 deficiency is far more common than most health care professionals and the general public realize. The Tufts University Framingham Offspring Study showed that approximately 40% of the population age 26 to 83 is deficient in vitamin B12. Other studies found that 50% of lacto-ovo vegetarians and 80% of vegans are deficient in B12 with signs of deficiency, typically manifesting within 22 months after the cessation of ingesting animal products. Conservative estimates on the elderly report that approximately 25% of those over age 65 are B12 deficient and many to a severe degree. Recent research shows that these percentages may be much higher due to faulty testing procedures and the normal range set too low to detect deficiency. Vitamin B12 deficiency can develop at any age beginning before birth and can have serious consequences if overlooked.

In their eye-opening book “Could It Be B12? An Epidemic of Missed Diagnoses”, authors Sally Pocholok, R.N., B.S.N. and Jeffrey Stuart, D.O. combine research and their professional experience in emergency medicine to present valuable information on this important issue. They explain that even with a diet high in B12-rich foods and supplements, it’s remarkably easy to become deficient because of the complex pathway that B12 takes to get from the mouth to the bloodstream. Dietary B12 is bound to animal proteins that must be freed in the stomach by pepsin which can be sufficiently produced only if there is enough available hydrochloric acid in the stomach. The parietal cells in the stomach produce intrinsic factor (IF) which is a protein that travels into the small intestine for a later key step in B12 metabolism. Other proteins called R-binders carry the B12 into the small intestine where the intrinsic factor latches onto the B12, and with the help of pancreatic protease enzymes, transports it to the last section of the small intestine, the ileum. The receptor cells that line the ileum grab onto the B12-IF complex and pull it into the bloodstream where another protein, transcobalamin II carries the B12 to the cells of the body and then delivers the excess to the liver for storage.

This complex process can break down at any point due to a variety of factors that prevent B12 absorption. The most widely known, yet less common condition is pernicious anemia, an autoimmune disorder where the body fails to produce intrinsic factor. A more common problem, especially for those over age 50, is atrophic gastritis, an inflammation and deterioration of the stomach lining. This reduces the secretion of hydrochloric acid needed to separate the B12 from protein which is often made worse by proton-pump inhibitors, H-2 blockers and antacid medications. Calcium, potassium and magnesium supplements taken with meals can also neutralize stomach acid and prevent digestion. Metformin, Colchicine, Questran, Neomycin, and Para-aminosalicylic acid are a few other drugs that interfere with B12 absorption. Cooking and pasteurization can deplete B12 in food as well as the enzymes needed to break it down. Pancreatic enzyme deficiencies which increase as we age contribute to B12 malabsorption. Older people also commonly have fewer parietal cells needed for the production of intrinsic factor, preventing B12 absorption. Gastric bypass, intestinal surgery, and overgrowth of pathogenic intestinal bacteria create roadblocks in the B12 absorption pathway. Celiac disease, IBS, and Crohn’s disease cause inflammation and degradation of the small intestines which impedes B12 absorption. Gluten is often the hidden culprit behind these conditions, and can interfere with B12 absorption in everyone at any age, even if there are no obvious symptoms of gluten sensitivity. Intestinal parasites rob B12. Eating disorders such as anorexia and bulimia rob the body of B12. Habitual alcohol consumption damages the GI tract, impairing the body’s ability to absorb B12 and other nutrients, however, alcohol may falsely indicate higher B12 levels in blood tests, masking an underlying deficiency. Smoking and exposure to pollutants decreases the body’s stores of B12. Nitrous Oxide (laughing gas) used recreationally and in surgery or dental procedures inactivates B12 causing serious consequences in those that are deficient. There are 10 known hereditary defects that can interfere with B12 absorption.

Because B12 deficiency mimics so many other diseases, including signs associated with aging, Pocholok and Stuart note that far too many cases of vitamin B12 deficiency go undiagnosed resulting in serious disease, disability and loss of life when this common condition can be easily recognized and successfully and inexpensively treated with B12 supplementation if caught soon enough. Left untreated, some conditions resulting from B12 deficiency may be irreversible. They point out that since adequate B12 is necessary to carry oxygen and iron in the blood, many doctors typically use the CBC or Complete Blood Count test to determine deficiency. However anemia generally occurs in the last stage of B12 deficiency long after other problems surface. The blood serum B12 test is also commonly used, however the authors feel that the lower range of normal for this test, 271-870 pg/ml, is too low. B12 deficiency occurs when levels fall below 550 pg/ml, so doctors can easily miss the first signs of deficiency when it is more easily treatable. Recent research suggests that the ideal level of blood serum B12 should be 1,000 pg/ml to 2,000 pg/ml for optimum health. The uMMA (Methylmalonic Acid) spot urine test is much more reliable and can be easily administered at home (available from Norman Clinical Laboratories 1-800-397-7408). Levels of urine methylmalonic acid over 3.8 ug MMA/mg creatine indicate B12 deficiency. A blood plasma test showing high homocysteine levels can also indicate B12 and/or folic acid (folate) deficiency, since these nutrients along with B6 are needed to break down the harmful protein homocysteine that contributes to cardiovascular disease and cancer. Cardiac patients are typically given high amounts of folic acid, however, folic acid will only lower homocysteine if there is an adequate supply of B12. This oversight can increase risk of heart arrhythmia, deep vein thrombosis, stroke, aneurysm, enlarged heart, congestive heart failure and heart attack. In addition, folic acid supplementation can mask B12 deficiency in blood tests, therefore consumption of over 1,000 mcg per day of folic acid without adequate B12 is not advised. According to some studies, vegetarians often have elevated homocysteine levels.

B12 plays an essential role in brain function and the production of myelin, the fatty substance that forms a protective sheath around the nerves. It is also needed to produce the “feel good” neurotransmitters serotonin and dopamine, sleep inducing melatonin, and acetylcholine which helps with memory and learning. Fatigue, anxiety, depression, foggy thinking, chronic pain, numbness or burning sensation in extremities, tremors, restless legs, and poor sleep may be due to a lack of adequate B12. Symptoms associated with aging including dementia, neuropathy, vertigo, frequent falls, Alzheimer’s disease, Parkinson’s disease and Multiple Sclerosis, and psychosis can all be caused by severe vitamin B12 deficiency. Psychiatrist and nutritional physician, John Dommisse, MD notes that he has had a near perfect track record treating patients with early Alzheimer’s disease, depression, and bipolar disorders by optimizing B12 levels. In Japan, the low end of the normal range for blood serum B12 is 2.5 times higher than in the U.S. and they have fewer cases of dementia, Alzheimer’s disease, depression and bipolar disorders than the U.S.

Adequate B12 is essential for fertility and healthy reproduction. Low levels of B12 have been associated with abnormal pap smears, HPV infection, chronic miscarriage, stillbirths, and postpartum depression in women. Men with B12 deficiency produce fewer sperm with poor morphology and have a greater chance of developing erectile dysfunction than those with healthy levels of B12. Children born to B12 deficient mothers are especially at risk. B12 and folic acid work together to prevent neural tube defects such as spina bifida in the developing fetus, yet prenatal vitamins typically contain high doses of folic acid (and low levels of B12 in cyanocobalamin form) which can mask B12 deficiency in blood tests. Nitrous oxide given during C-sections inactivates B12. Vaccines containing mercury also deactivates B12 creating a rough start for these children. Children that are born to and breastfed by B12 deficient mothers commonly have a higher risk of developmental delays, failure to thrive, colic, learning problems and in severe deficiency, autism. B12 deficiency is so common, that a 2001 pediatric study found that 1/3 of infants born to non-vegetarian mothers were deficient in B12. This dire situation could be avoided with proper screening and prenatal supplementation of 1,000 mcg of sublingual methylcobalamin per day.

The endocrine and immune systems require adequate B12 to function properly. Vitamin B12, like folic acid, is a methyl donor which means that it contains a methyl group (a carbon atom attached to 3 hydrogen atoms) which it can transfer to another substance. This process, called methylation, is important for many biochemical functions throughout the body including energy metabolism, immune function, nerve function, and detoxification. Methyl donors play an important role in detoxifying synthetic chemicals and bad estrogens that cause hormonal imbalance and cancer. Methylcobalamin is particularly effective for this purpose. B12 deficiency causes defects in the methylation process which can turn healthy cells into cancerous cells. Fibromyalgia, diabetes, Hashimoto’s thyroiditis, Graves’ disease, lupus, rheumatoid arthritis, Addison’s disease, vitiligo and other autoimmune disorders are strongly associated with insufficient B12. Sore tongue, premature graying of hair, and missing moons on the fingernails may also signify B12 deficiency. B12 helps to reset the biological clock and balance melatonin and serotonin levels for deep restful sleep and energy during the day. Sleep apnea and shortness of breath can also be helped with B12 supplementation. Athletes take B12 shots or supplements to increase energy and endurance.

Vitamin B12 deficiency suppresses the production of osteoblasts that build bone and impacts the integrity of spinal nerves and discs, contributing to osteoporosis, fractures, sciatic pain, and disc issues. B12 deficiency also plays a role in hypotonic and hyperactive bladder issues and incontinence.

To build up from deficiency 1,000 mcg to 2,000 mcg per day of sublingual methylcobalamin may be sufficient. In cases of pernicious anemia or advanced disease, B12 injections may initially be required. Methylcobalamin injections are best as this form of B12 will cross the blood-brain barrier which is especially important in cases of neurological disorders. Since the B vitamins work together, folic acid and B6 or a B-complex formula should also be taken.

Awareness and education on the importance of vitamin B12 can improve the quality of life for many who have suffered and help future generations live in optimal health.