vitamin B12 deficiency

Vitamin B12 Deficiency

Vitamin B12 or cyanocobalamine is among the important vitamins for optimal nervous tissue and blood functions. It belongs to the chemical group referred to as corrinoids. Depletion of vitamin B12 in the nervous system results in a condition called subacute combined degeneration of the spinal cord. Elderly persons are more susceptible to this condition, which could result in dementia. Depletion of B12 and folic acid also results in a type of anemia called megaloblastic anemia, where the red blood cells are larger than normal. Vitamin B12 requirements increase during pregnancy to meet the demands of the growing fetus.
Vitamin B12 deficiency is detected by testing the blood for vitamin B12 levels. This test is usually done in individuals suffering from megaloblastic anemia or dementia and other nervous system problems.

Some amount of vitamin B12 is synthesized by the bacteria in the intestines. Vitamin B12 in the diet is mainly obtained from animal sources. Thus, non-vegetarians usually do not suffer from vitamin B12 deficiency unless they have some other additional problems. However, with more and more people choosing to become vegetarians, it has become important to emphasize on the vegetarian sources of vitamin B12. Milk and certain dried algae are known to contain the vitamin. The problem could be more acute in vegans, who will require vitamin B12 as tablets or in fortified foods to meet their requirement.

The presence of certain inactive corrinoid compounds could affect the availability and activity of vitamin B12 in the body, thus resulting in a deficiency state despite adequate intake. In addition, tablets containing certain bacteria like Spirulina, Aphanizomenon, and Nostoc could also affect the activity of B12 in foods. Though Spirulina and the other supplements are high in B12 content, some researchers feel that this form of B12, which they refer to as pseudo-B12, may not be biologically active in humans, and in fact may reduce the effect of B12.

The cooking method could also affect the vitamin B12 content of the food. Researchers suggest that cooking at high temperatures and for long periods could reduce the vitamin B12 content of fish. They also suggest that vitamin B12 is lost even when food is microwaved. Vitamin B12 in tablets also undergoes degradation if they contain high amounts of vitamin C and copper.

Some of the foods suggested by the researchers as high in vitamin B12 content are:

 Fermented soyabeans and fermented vegetables including tea leaves. The fermentation process adds vitamin B12 to these vegetarian foods.

 Two species of edible algae – dried purple and green lavers

 Black trumpet and golden chanterelle mushrooms

 Vegetables enriched in vitamin B12 during the cultivation process

 Fortified B12-containing foods like ready-to-eat cereals

Thus, vitamin B12 deficiency can be carefully avoided in vegetarians through careful planning of their diet.


1. Biologically Active Vitamin B12 Compounds in Foods for Preventing Deficiency among Vegetarians and Elderly Subjects; Fumio Watanabe et al; J. Agric. Food Chem., 2013, 61 (28), pp 6769-6775 DOI: 10.1021/jf401545z

Neuropathy and Vitamin B12 Deficiency

General disturbances in the normal functioning of the peripheral nerves are known as neuropathy. There are many neurological manifestations of vitamin B12 deficiency, namely, alcoholic neuropathy (resulting from extended alcoholism), peripheral neuropathy, diabetic neuropathy(resulting from diabetes), and optic neuropathy, which is a rare. Neuropathy treatment always focuses on addressing the root cause, such as alcoholism or diabetes. Regular exercise helps to provide stability to the muscles. 

Additionally, there is a common link between nutrition and neuropathy. Since vitamin B12 supports the sheathing that coats the nerve cells, people with vitamin B12 deficiency often suffer from peripheral neuropathy. In order to fight this, foods that are high in vitamin B12 such as meat, fish, and eggs need to be consumed. Fortified cereals are also good for vegetarian patients. 

Since Vitamin B12 is not created by the body itself, one has to consume foods-rich in B12 in order to avert vitamin B12 deficiency. Moreover, although vitamin B12 can be stored in the body, it is not easily absorbed by the body, and this inability further leads to vitamin B12 deficiency, which, in turn, leads to peripheral neuropathy. Peripheral neuropathy results in burning, tingling, shooting pain, and numbness in the legs, feet, and hands. It lessens the ability of the body to sense pain, temperature, touch, and vibration. The occurrence of peripheral neuropathy increases with age and vitamin B deficiency. There is also a link between vitamin B12 and muscle cramps. Low levels of vitamin B12 lead to muscle weakness and cramps. 

Causes of vitamin B12 deficiency include the following: 

  • A Strict Vegetarian Diet: Animal-based foods are the only recognized source of vitamin B12 and lack of that in a vegetarian diet results in vitamin B12 deficiency.
  • Reduced Ability of Absorption of B12: Diseases like autoimmune disorders, pancreatic diseases, HIV infection, malabsorption syndromes, and Crohn’s disease reduce the stomach acids that aid in the absorption of B12, resulting in deficiency.


B12 Neuropathy Recovery

B12 neuropathy recovery can be obtained by increasing the intake of vitamin B12 in one’s diet; this can be done by adding red meat, poultry, eggs, fish, and dairy products to one’s daily meals. Vitamin B12 supplements are also a good option, as are B12 injections and oral B12 tables, which are usually prescribed for B12 neuropathy recovery. 

Since vitamin B12 deficiency results in nerve damage, patients often suffer from an unsteady walk, muscle spasms, shaky movements, and muscle weakness. Some of the home remedies for nervous weaknesses include eating a diet high in fruits and vegetables. Good sources of vitamin E such as breakfast cereals, whole grain, vegetables, and nuts are also good for neuropathy treatment in the case of vitamin B12 deficiency. Lean protein sources such as skinless white meat poultry, legumes, tofu, fish, low fat yogurt also helps to treat deficiency of vitamin B12 and neuropathy.

For diabetes, it is important to be careful of too much fruit sugar. A serving of half a banana, apples, and non-starchy vegetables such as greens and asparagus are effective for treating diabetic neuropathy. Neuropathy is a common side effect of diabetes and one of the prime causes for diabetic neuropathy is vitamin B12 deficiency. Since peripheral nerves have the ability to regenerate, symptoms can be controlled provided the nerve cell has not been killed. Eliminating the cause help to prevent further damage. If the cause is due to imbalanced diet, intravenous injections of vitamin B12 along with dietary changes are often prescribed by the physicians to treat the problem. Pain can be reduced with prescribed medications such as anticonvulsants and tri cyclic antidepressants.

At present, there is no medical treatment for inherited peripheral neuropathy. Neuropathy treatment and reversal of vitamin B12 deficiency can be achieved by treating the underlying problems followed by symptomatic treatment. 

Since the neuropathy is almost irreversible in most cases, the treatment mainly focuses on preventing further progression. Neuropathy treatment includes lifestyle changes like avoiding alcohol, eating a balanced diet, correcting vitamin deficiencies, maintaining optimum weight, and reducing stress, etc. 

In order to meet the requirement of B12, intake of a wide variety of animal products is the best way. However, for vegans, multivitamins, B12 injections, B12 nasal gels, and sublingual forms are prescribed. The RDA (recommended dietary allowance) depends on the age, gender and other factors such as pregnancy and illness.