Vitamin B12 (Cobalamin) — uses, deficiency & supplements
Although all eight of the water-soluble B vitamins are important for many aspects of health, B12 is probably the most significant. From conception to death, B12 plays a key role in the formation of red blood cells, proper nervous system functioning and DNA synthesis. Countless studies and reports show that a deficiency in B12 during pregnancy can be devastating to the developing baby. Not only can severe birth defects develop but also irreparable brain and nerve damage can result, leaving these children disabled for life.
B12 was only discovered in 1947, at which time it was the last of the B vitamins to be isolated. B12 is easily recognized by its characteristic deep red color, aptly being nicknamed the ‘red vitamin’. B12 is actually a combination of several compounds, called cobalamins — hydroxocobalamin, nitrocobalamin, and thiocyanate cobalamin — all of which contain the trace mineral cobalt.
During pregnancy the baby is reliant on the mother for its nutritional needs. Most nutrients (and other substances) consumed by the mother, travel through the placental wall to the growing fetus where they are used to assist in its healthy development. Mothers who fail to eat a well balanced diet or take prenatal vitamins, put their babies at serious risk. Once born, the baby still relies on its mother for all of its nutritional requirements. Breast-fed babies especially are completely bound by the nutritional intake of their mothers.
Infants at the risk of B12 deficiency
Although B12 deficiency is rare among infants, it can still occur. Those that are at risk are breast-fed babies of mothers who are vegans (strict vegetarians consuming no animal products, which are the main source of B12) as well as breast-fed babies of mothers who have gastrointestinal problems such as Chron’s disease, an inflammatory bowel disease that affects the intestines, or other conditions that affect fat absorption.
Babies that suffer from such problems as celiac disease, a genetic disorder that prevents the synthesis of a protein called gluten, are also at risk for a B12 deficiency. Signs in infants can develop quite quickly and include a failure to thrive, delayed development, movement or nervous disorders and a type of anemia called megoblastic anemia whereby red blood cells also called erythrocytes, grow to an abnormally large size.
Vitamin B12 can be stored in the body
Ironically, the body only requires very small amounts of B12 to function properly, but a deficiency in the vitamin can have very large, and for the most part, irreversible repercussions. Scientists report that the body requires only 3/1,000,000 of a gram per day (or 3 mcg.) of B12 to function efficiently. Further, it is surmised that a healthy person carries close to a five-year supply of B12 in their body at any given time. One milligram is said to meet our physiological needs for a two-year period. B12 is also believed to be the only B vitamin that can be stored for later use, no matter how far off that time may be.
B12 is only produced by bacteria and as such is only found in animal sources or some fermented products such as miso, fermented soybeans. When B12 first enters the stomach, it must combine with a substance called intrinsic factor (IF), which is necessary for B12 to be absorbed by the small intestine. Once absorbed by the liver, it is stored and made readily available for later use. Even with a total absence of IF, once stored, research shows that these amounts are still enough to sustain the needs of the average person for several years.
Deficiency of Vitamin 12
Low levels of IF and hydrochloric acid (stomach acid) however, can lead to a deficiency, especially in the elderly who have likely depleted their B12 stores. This deficiency may also go overlooked for some time, only being diagnosed after the fact because symptoms of B12 deficiency typically develop very slowly, sometimes taking up t o 10 years,
Probably the most significant signs of a deficiency are anemia, weakness, fatigue, constipation, loss of appetite and resulting weight loss. In more prolonged incidences, neurological effects such as numbness and tingling in the hands and feet may develop. Eventually, depleted stores could lead to dementia and confusion, a difficulty in keeping balance, severe depression and poor memory.
Vitamin deficiency is manifested after 10 years
According to one study B12 deficiency is becoming more of a problem starting in people as young as 26. This study looked at people in three age groups; 26 to 49, 50 to 64 and 65 and older. It was concluded that the amount of deficiency was actually similar across all age groups, but that the symptoms in the older people were more pronounced, This is not surprising considering research also shows it can take up to 10 years for deficiency signs to manifest. This study further reported however, that people who do not use supplements containing B12, such as a multivitamin, have a 50 percent risk of developing a deficiency compared to those that do take a supplement, regardless of their age1 This same study also shows that individuals who choose not to take supplements but eat fortified cereals at least four times per week, do not have the same risk of deficiency.
WThe elderly are at risk for many medical conditions and B12 deficiency is no exception. Stomach problems seem to be the biggest barrier to B12 absorption for this group and in fact, up to 30 percent of adults over 50 have what is known as atrophic gastritis. This is a condition in which the stomach becomes inflamed, decreasing the gastric juices, lowering their ability to absorb B12. As a secondary complication, the normal bacteria within the stomach increase to abnormal levels, using up any available B12 sources for their own use. Studies show that these people can however, absorb the synthetic form of B12, usually found in supplements and fortified foods.2
Symptoms of B 12 deficiency
Anemia is the most commonly associated symptom of a B12 deficiency. This condition results when there is not enough hemoglobin in the blood to carry oxygen to the cells and tissues. There are several types of anemia and as well, a variety of other medical problems including a deficiency in Vitamin B6
, Vitmin B9
, (folic acid), andI iron
that can also be the root cause. In the past, pernicious anemia was quite common, often having fatal results. This particular anemia results from a primary condition in which the gastric cells are prevented from secreting IF necessary for B12 absorption. Today, this disorder is resolved with a B12 intravenous drip until such time as sufficient stores are replenished, after which a B12 supplement is prescribed.
Vitamin B12 decreases homocysteine level
Dementia is another unfortunate result of B12 deficiency. Recent studies show that low levels of B12 may also lower the levels of substances needed in the synthesis of neurotransmitters, the chemicals that transmit signals to other nerves. It is further shown that decreased neurotransmitters negatively affect cognitive ability. Additional research compared cognitive skills with homocysteine levels. This amino acid, normally found in the blood, when elevated, has been linked to heart disease and stroke. Elevated levels of homocysteine according to research, may also impede blood vessel flow, causing damage to the coronary arteries and as well, promoting blood clots, all of which can lead to heart attack. One study concluded that elevated homocysteine levels are significantly associated with a decrease in cognitive ability.3
Homocysteine levels were further studied in correlation to heart disease and B12. It was found that supplementation with both B12 and B9 (folic acid) will lower homocysteine levels in subjects already suffering from heart disease and as well as young women. Another study reported that a multivitamin taken for 56 days can also lower homocysteine levels in both older men and women.4
Vitamin B12 & drug interactions
To date, there are no reports of toxicity associated with vitamin B12, even when used a very high doses such as injections. In fact, doses of up to 3,000 mcg are considered safe. There are a few drug interactions associated with B12 however, including Metformin©, a common medication used to treat diabetes. This drug is found to interfere with the synthesis of calcium, which may indirectly reduce the ability of the body to absorb B12. Clinical observations show that as many as 30 percent of people taking Metformin© have reduced B12 absorption. It is always wide therefore, if you are taking any type of medication to consult a health professional before taking any supplements or herbs since theses substances are known in many cases, to have interactions.
- Tucker KL, Rich S, Rosenberg I, Jacques P, Dallal G, Wilson WF, Selhub. J, “Plasma vitamin B12 concentrations relate to intake source in the Framingham - Offspring Study”, Am J Clin Nutr, 2000;71:514-22.
- Krasinski SD, Russell R, Samloff IM, Jacob RA, Dalal GE, McGandy RB, Hartz SC, “Fundic atrophic gastritis in an elderly population: Effect on hemoglobin and several serum nutritional indicators”, J Am Geriatr Soc, 1986;34:800-6.
- Vital Trial Collaborative Group. “Effect of vitamins and aspirin on markers of platelet activation, oxidative stress and homocysteine in people at high risk of dementia”, Journal of Internal Medicine, 2003; 254:67-75.
- McKay DL, Perrone G, Rasmussen H, Dallal G, Blumberg JB, “Multivitamin/Mineral Supplementation Improves Plasma B-Vitamin Status and Homocysteine Concentration in Healthy Older Adults Consuming a Folate-Fortified Diet”, Journal of Nutrition, 2000;130:3090-6.