Vitamin B12 – an important protection for strong nerves

TOPIC OVERVIEW

Owing to its function in cell formation and lipid metabolism, vitamin B12 plays a vital role for the nervous system. It is crucially involved in the regeneration and new formation of the nerve fiber sheaths (also known as myelin sheaths) that protect nerves from a loss of charge and ensure the correct and effective transmission of nerve flows, i.e. the information to be forwarded.

Babies and children need a lot of vitamin B12 because of their growth. They depend on a sufficient supply of vitamin B12 that hast to be provided by attentive parents. Seniors and vegans are especially affected by vitamin B12 deficiency. Whereas vegans are at risk for not getting enough vitamin B12 owing to their unbalanced diet that excludes foods of animal origin, senior citizens are often affected by impaired B-vitamin absorption, but nutritional limitations sometimes are common as well. Persons suffering from chronic diseases such as diabetes, kidney insufficiency or dementia have impaired B12 absorption – frequently due to side effects of the active ingredients and medication taken over a long period of time – and are at risk for a deficiency. Persons who suffer from inflammation of the gastric mucosa or other digestive tract conditions are unable to synthesize important substances needed for absorbing the vitamin on their own, that some of the vitamin B12 supplied is once again excreted unused.

Especially as we age, several of these factors accumulate to increase the risk for vitamin B12 deficiency. Whereas only about 2-5% of young Europeans are affected by vitamin B12 deficiency, 10-30% of persons over 65 are diagnosed with vitamin B12 deficiency. If they live in a retirement home, their proportion even increases to about 40%.  

Regardless of the cause – if a vitamin B12 deficiency is detected too late, partially irreparable nerve damage looms.

Initial symptoms of vitamin B12 deficiency are mostly non-specific lack of energy and poor performance, as well as unsteadiness in the legs. The poorly functioning nerves in the spinal cord often trigger false sensations in the lower extremities at first, like burning and numbness in the feet, and a tight, cuff-like feeling in the calves. Since the brain, neurotransmitters, and hormones are also affected, vitamin B12 deficiency can additionally cause concentration problems, poor memory, and depression.

If vitamin B12 deficiency remains undetected for a long time, serious neurological and neuropsychiatric conditions, that can even progress to dementia and schizophrenia, can be the result. Also, strong physical limitations that can even lead to paraplegia can be triggered by vitamin B12 deficiency. The funicular myelosis is responsible, in which the spinal cord is damaged owing to a lack of nerve sheaths. If the deficiency is detected early, some damage can be reversed. However, if the consequences of vitamin B12 deficiency have progressed too much, nerve damage is irreparable. Therefore, an insufficient supply of vitamin B12 should by all means be taken seriously and should be prevented.

After absorption through the food, vitamin B12 goes to the blood in various steps: With the food, it first reaches the stomach – where the so-called intrinsic factor is formed, to which vitamin B12 is bound. Together, they can be absorbed in the small intestine and reach the blood. A good bit of the vitamin can also diffuse through the intestinal walls without the intrinsic factor. Once it is inside the body, it is present in an active form (that the body can use) and in an inactive form as well. Only about 20% of the vitamin B12 in the blood is active and is known as holotranscobalamin (abbreviated HoloTC). Since a blood test also detects the inactive vitamin B12 in the blood, it can deceive a vitamin B12 deficiency diagnosis, i.e. disguise a deficiency. If the person belongs to a risk group or there is suspicion owing to the appearance of various vitamin B12 deficiency symptoms, a specific two-step blood test should be performed. In it, the holotranscobalamin content is determined and the second step determines the concentration of metabolic products, resulting from the lack of vitamin B12, such as methylmalonic acids and homocysteine. If both tests have an unfavorable result, a vitamin B12 deficiency can be assumed, which should be cured as quickly as possible.

Although vitamin B12 is crucial for our body, we need only relatively low quantities of it. The daily recommended dose for healthy adults is 3 µg. Children need somewhat less vitamin B12, whereas pregnant and breastfeeding women need more of it, namely from 3.5 to 4 µg a day.

Vegans and other persons who due to a unbalanced diet are at risk for consuming too little vitamin B12 can prevent an insufficient supply of B12 relatively easy through a vitamin B12-conscious diet or a specific vitamin B12 supplementation. Vitamin B12 is synthesized by microorganisms and is found almost exclusively in foods from animal origin –above all in the liver, where animals store it. However, meat, fish, eggs, milk, and dairy products have considerable quantities of the vitamin. Therefore vegans are recommended to compensate for the potential existing deficiency by taking supplements (which, by the way, are generally vegan). Once a vitamin B12 deficiency has been detected, suitable medication should be taken as part of a therapy prescribed by your physician.

If the absorption capability for vitamin B12 is impaired, the trigger must be found first. The triggers can be poor formation of the intrinsic factor in the stomach or inhibited absorption caused by medications, as is the case with metformin, for example, used by many persons with type 2 diabetes. When medications are used for a long time, vitamin absorption is generally affected, but increasing the supply of vitamin B12 can compensate for this.

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