Vitamin B12 Deficiency: Symptoms And Causes

Cobalamin is a key water-soluble vitamin in our body. Its widespread deficiency, associated, as a rule, not only with the restriction of the intake of products containing it, but also arising from the violation of the processes of absorption and further distribution, is one of the most frequent problems that are addressed to a nutritionist.

Anemia, impaired functioning of the nervous system and the transmission of impulses from one neuron to another, damage to the inner lining of blood vessels - this is just a small part of the list of pathologies that B12 deficiency leads to. How to suspect and diagnose his beriberi in time? What type of diet contributes to the prevention of cobalamin deficiency? Let's figure it out.

Vitamin B12 metabolism

Cobalamin enters the human body along with animal products. Our body is not able to independently reproduce its synthesis - it is a product of exclusively bacterial activity.

First of all, this is due to the fact that the main absorption processes take place in the small intestine, and not in the large intestine, which is much more populated by bacteria. In other words, in order for the formed vitamins to be absorbed, their synthesis must occur in the duodenum, jejunum or ileum - in those sections of the gastrointestinal tract, the epithelium of which has specific villi.

However, this does not happen - and the diversity of the bacterial world of the small intestine is not without reason inferior in many respects to the large intestine: the latter has the most optimal conditions for growth and reproduction. The remains of undigested food and the lack of the need to constantly resist the current of the advancing food bolus - what could be better?

Thus, whether we like this fact or not, we can cover the needs of our body purely from the outside - either with food or with dietary supplements.

Once in the digestive tract, vitamin B12 binds in the stomach with a specific protein produced by epithelial cells. Here, the internal factor of Castle is synthesized - a protein-carbohydrate compound, which, in fact, is an enzyme that converts cobalamin into an absorbable form. The formation of a complex between it and B12 (which normally occurs in the alkaline environment of the initial sections of the small intestine) is a necessary condition for the occurrence of further absorption processes.

In the underlying sections, B12, by binding to specific receptors on the inner epithelial lining, enters the systemic circulation through intestinal enterocytes, where it is carried throughout the body with the help of protein molecules.

This is the only vitamin from the group of water-soluble that is capable of being deposited - its main pantry is the liver, which must be taken into account when prescribing and taking high doses of the drug.

Functions of cobalamin

The most important function of cobalamin is coenzymatic: it takes part in the functioning of two enzymes:

• Methylmalonyl-CoA mutase - catalyzes the formation of succinic acid, which is involved in such an energy pathway as the Krebs cycle.

  Genetically mediated insufficiency of this enzyme manifests itself in the form of severe disorders and often leads to death. In addition, a decrease in its activity leads to the accumulation of metabolites in tissues, which cause demyelination of nerve fibers. This pathological process causes a violation of the integrity of that insulator - myelin - due to which impulses are transmitted strictly along one process of the neuron, without spreading to others.

  In general, ideas about the participation of cobalamin in the course of the above reaction are necessary for understanding the ongoing diagnostic measures in order to determine B12 deficiency - we will talk about them a little below.

   

• Methionine synthase, which ensures the conversion of amino acid homocysteine, notorious for its negative effect on the endothelium (inner lining), back into methionine, the derivative of which (S-adenosyl methionine), in turn, promotes methylation reactions. These biochemical processes are necessary for “turning on” and “turning off” certain genes in the DNA structure, as well as for neutralizing inflammatory mediators and the formation of many biologically active substances - for example, membrane phospholipids, hormones of the adrenal medulla (adrenaline).

  The transfer of the methyl group is a kind of hot potato game at the level of biochemistry: its original donor, the active form of folic acid (methyltetrahydrofolate), “dumps” it onto B12 with the formation of methylcobalamin, in fact, the compound that is involved in the transformation of homocysteine.

  Schematically, the sequence of transfer of the methyl group can be represented as follows: Methylenetetrahydrofolate - methyltetrahydrofolate - methylcobalamin - homocysteine

   

  Three main genes are involved in the regulation of the folate cycle (methylation cycle):

  • MTHFR

  • MTR

  • MTRR

  Their polymorphism (let's call it a "breakdown" for a simpler understanding) leads to the difficulty of neutralizing homocysteine ​​- its content in the blood naturally increases, leading to adverse effects on the part, first of all, of the cardiovascular system.

  The fact is that homocysteine ​​disrupts one of the key stages in the maturation of collagen protein, inhibiting the work of the corresponding enzyme. As a result, the structure of the main protein of the connective tissue, the fibers of which are included, in particular, in the composition of the vessel wall, is disturbed as a result of this, manifests itself as fragility of the capillaries.

   

Causes of Vitamin B12 Deficiency

1. Insufficient intake of cobalamin with food - in particular, occurs in patients who adhere exclusively to a plant-based diet and do not compensate for the body's needs for this vitamin in the form of dietary supplements.

1. Digestive system disorders:

   • a decrease in the formation of the internal factor of Castle due to a decrease in the number of functioning cells - noted in atrophic gastritis;

   • autoaggression - the formation of antibodies against the internal factor of Castle;

   • damage to the gastric mucosa due to excessive secretion of hydrochloric acid, the spread of H. pylori infection from the pyloric region around the entire perimeter of the organ;

   • malabsorption on the epithelial villi of the small intestine - in particular, is characteristic of celiac disease.

    

2. Exposure to stress factors mediates the formation of cortisol by the adrenal cortex, which worsens the blood supply to the gastric mucosa due to the development of arterial spasm.

3. Old age - normally there is atrophy of some structures and even tissues, representing a reverse involution.

4. Parasitic invasion - there is competition for cobalamin of the host macroorganism with protozoa (giardia) and helminths (tapeworms).

5. Taking medications:

   • reducing the formation and release of hydrochloric acid: proton pump inhibitors, antagonists of H2-histamine receptors;

   • metformin - is prescribed to correct carbohydrate metabolism (mainly diabetes mellitus);

   • colchicine - used in the treatment of gout.

   Research: Modern possibilities for the diagnosis and treatment of vitamin B12 deficiency

    

Vitamin B12 deficiency symptoms

Clinical manifestations are quite extensive and affect not only the hematopoietic system. They vary in severity - especially in the context of neurological impairment.

In addition, it must be remembered that B12 is able to accumulate in the liver (for ten years or more!) - this can largely delay the manifestation of characteristic symptoms.

Recommended daily dose of B12

In American protocols, as a preventive measure for B12 deficiency, daily intake is recommended: for adult men and non-pregnant women - 2.4 mcg; during gestation - 2.6 mcg.

Diagnosis of vitamin B12 deficiency

1. General blood analysis:

   • a decrease in the mean volume of erythrocytes (MCV);

   • increase in mean platelet volume;

   • an increase in MCHC - the average concentration of hemoglobin in erythrocytes.

    

2. An indirect marker is an increase in the concentration of homocysteine ​​in the blood serum.

   It should be understood that folic acid is also involved in the processes of neutralization of this amino acid - accordingly, a lack of vitamin B9 will also lead to the accumulation of homocysteine.

    

1. Sensitive markers:

   • determination of the level of methylmalonic acid in organic acids in the urine;

   • holotranscobalamin.

    

2. Clinical blood test:

   • hypersegmented neutrophils;

   • macrocytic anemia.

    

3. Determining the concentration of cyanocobalamin is not always a diagnostically important marker: after all, an increased concentration of this form of vitamin B12 in the blood does not exclude its low level in the cells themselves.

In general, in domestic medicine, the definition of the following degrees of cobalamin deficiency is used:

Given the close relationship between gastrointestinal health and normal cobalamin absorption, mucosal inflammation must also be ruled out.

How to make up for the lack of vitamin B12

First of all, it is necessary to establish the cause of the deficiency: it can be either a polymorphism of the main genes that regulate the folate cycle, or disorders of the digestive system, in particular, gastritis. Based on this, you can build a clear strategy for working with a nutritionist or, in more difficult situations, seek advice from a doctor.

In the case of parasitic invasion, one should begin with the establishment of the formation of hydrochloric acid and bile outflow - nonspecific factors of natural protection. However, such activities can be carried out only if the integrity of the epithelial integument is always paramount - the integrity of the mucous membranes (especially given the irritating effect of both digestive secrets).

Correction of hypochlorhydria includes:

1. Working with the folate cycle - determining polymorphisms in the main regulatory genes (MTHFR, MTRR, MTR) and, if they are present, taking vitamins in their active forms:

   • riboflavin-5-phosphate (B2);

   • pyridoxal-5-phosphate (B6);

   • methylfolate (B9);

   • methylcobalamin (B12).

    

2. Taking drugs that increase the level of acidity of gastric juice:

   • trimethylglycine (betaine);

   • iodine;

   • zinc.

    

3. When spreading H.pylori around the entire perimeter of the stomach or when determining its aggressive strains, antibiotic therapy is indicated (in order to eradicate it) for 2 weeks under the supervision of a gastroenterologist.

4. Elimination of stress factors: cortisol produced by the adrenal cortex, as previously mentioned, leads to a spasm of blood vessels supplying the stomach wall.

   As an aid to lower cortisol levels, you can use:

   • motherwort;

   • rhodiola rosea;

   • dried basil.

    

5. Increased vagus nerve tone: all digestion processes are controlled by the vagus. Perfect for this purpose:

   • breathing practices;

   • meditation;

   • yoga;

   • relaxing massages;

   • salt baths.

    

6. Stimulation of the synthesis of such a tissue hormone as prostaglandin E1, which provides not only the formation of a protective layer of mucus that prevents irritation of the inner lining of the stomach, but also activates the release of hydrochloric acid.

   The initial substrate for its synthesis is arachidonic acid, which belongs to the omega-6 polyunsaturated fatty acids. In addition, gamma-linolenic acid is also involved in the process.

   From dietary supplements, we recommend paying attention to:

   • borage oil;

   • evening primrose oil.

    

Bile flow correction:

Initially, it is necessary to establish the cause of the violation of bile flow: it can be banal hypokinesia or, much more seriously, the formation of stones - and not all of their varieties can be dissolved. So, ultrasound of the abdominal organs is the first step towards the goal.

In addition, it should be clearly understood: in case of damage to the intestinal epithelium, stimulation of the gallbladder will lead (due to the irritating effect of the secretion secreted by it) only to deterioration, significantly inhibiting regeneration processes - the latter, taking into account the rate of proliferation (multiplication) of enterocytes, can turn into an unpleasant surprise in the form of a neoplasm.

One of the most common causes of bile stasis is a violation in the ratio of its components: cholesterol largely prevails over phospholipids and bile acids. This, in particular, is typical for a high-carbohydrate diet: the entire excess of this class of organic compounds, which was not included in the biochemical pathways for obtaining energy, and also did not turn into glycogen in the liver cells, is transformed into fat, ultimately leading to a decrease in bile fluidity. .

First of all, nutritional correction is necessary: ​​the rejection of any kind of snacks and the transition to a 3-time diet. In addition, preference should be given to complex carbohydrates: long-cooked cereals, vegetables, herbs and berries. To support bile flow, you can consider taking the following supplements:

• taurine and glycine - take part in the metabolism of bile acids;

• sunflower lecithin;

• phosphatidylserine.

Given that bile is involved not only in the emulsification of fats, but also acts as an activator of pancreatic enzymes, in some cases, violations of its secretion can lead to exocrine pancreatic insufficiency. And the first, as a rule, is lipase, an enzyme that breaks down chemical bonds in fat molecules.

Lipase deficiency can be identified by the following signs:

• greasy, sticking to the walls of the toilet, stool with an unpleasant odor;

• fat-soluble vitamin deficiencies and their accompanying symptoms.

In such cases, the doctor individually selects the drug based on the appropriate enzyme and calculates the required dosage.

What form to take B12

Disputes regarding the effectiveness of oral and parenteral therapy have been going on for a long time. Doctors can not come to a general consensus about whether it is still necessary to prescribe patients with cobalamin deficiency: pills or injections.

In the presence of ulcers, gastritis and other inflammatory processes in the mucosa of the gastrointestinal tract, it will be much more effective to take sublingual drugs: due to the good blood supply to the oral cavity, the drug is quickly absorbed and immediately enters the systemic circulation.

We would also like to share the results of one small study in which 1838 patients with B12 deficiency were divided into two groups: the first received 1000 micrograms of the vitamin in the form of intramuscular injections, the second - orally. After 4 months, serum levels of cyanocobalamin and urinary methylmalonic acid were significantly higher in those who received parenteral treatment. Moreover, the effectiveness of the latter was noted even in the category of volunteers who had undergone gastrectomy at one time.

Foods rich in vitamin B12

As mentioned above, cobalamin is one of the few vitamins that can only be taken with food of animal origin, and the formation process inside the human body is inefficient.

So, here is a small list of products that, in our opinion, make up the top sources of cobalamin richest: