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Vitamin B12 – It’s Deficiency Symptoms, Role

What is Vitamin B12 ?

Vitamin B12, also known as cobalamin, is a water-soluble vitamin that plays a crucial role in many bodily functions. It is essential for the formation of red blood cells, neurological function, and DNA synthesis. Vitamin B12 is not produced by the human body, so it must be obtained through diet or supplements. Methylcobalamin is an activated form of Vitamin B12.

Discovery Of Vitamin B12 :-

Vitamin b12 was discovered because of its relationship to the disease pernicious anemia (PA). PA was a fatal illness before the 1920s. But this changed after Whipple suggested raw liver as a treatment. He found that ingesting large amounts of liver seemed to cure anemia from blood loss. Minot and Murphy then described the dramatic recovery of 45 patients suffering from PA after they consumed a special diet of lightly cooked liver. The three men shared the 1934 Nobel Prize in Medicine for the discovery of the cure of a previously fatal disease of unknown origin. The active anti-PA factor was a mystery until 1948, when folkers and smith independently isolated a small quantity of a red crystalline compound from liver. After the substances was shown to lead directly to the recovery of PA patients it was named vitamin B12.

Role Of Vitamin B12 in Body :-

Vitamin B12 plays several crucial roles in the body, and its functions are essential for maintaining overall health. Here are some key roles of vitamin B12 in the body:

  1. Red Blood Cell Formation : Vitamin B12 is necessary for the synthesis of hemoglobin, the protein in red blood cells that carries oxygen from the lungs to the rest of the body. Adequate B12 levels are crucial for preventing megaloblastic anemia, a condition characterized by large, irregularly shaped red blood cells.
  2. Neurological Function : B12 is essential for the maintenance of the nervous system. It is involved in the production of myelin, a fatty substance that coats and insulates nerve fibers. Myelin helps nerve impulses travel efficiently along the nerves. A deficiency in B12 can lead to neurological symptoms such as numbness, tingling, difficulty walking, and memory problems.
  3. DNA Synthesis : Vitamin B12 is required for the synthesis of DNA, the genetic material present in every cell. It is involved in the conversion of methylmalonyl-CoA to succinyl- CoA, a critical step in DNA synthesis and cell division.
  4. Energy Metabolism : Vitamin B12 is involved in the metabolism of fatty acids and amino acids. It helps covert these nutrients into usable forms for energy production. As a result, B12 contributes to the overall energy metabolism in the body.
  5. Methylation Reaction : Vitamin B12 is a cofactor for methionine synthase, an enzyme involved in methylation reactions. Methylation is a vital process in the body that influences gene expression, neurotransmitter synthesis, and various metabolic pathways.
  6. Cell Division and Growth : B12 is essential for the normal growth and division of cells. This is particularly important for rapidly dividing cells, such as those in the bone marrow and the gastrointestinal tract.
B12 Dependent Enzyme :-

Vitamin B12 plays a crucial role as a cofactor for two important enzyme :

  1. Methionine Synthase : Methionine synthase is an enzyme that plays a key role in the conversion of homocysteine to methionine. Methionine is an essential amino acid that is important for protein synthesis. This reaction is also vital for the regeneration of tetrahydrofolate (THF), a form of folic acid, which is involved in DNA synthesis. Vitamin B12 serves as a cofactor for methionine synthase, facilitating this conversion and contributing to proper methylation reaction in the body.
  2. Methylmalonyl-CoA Mutase : Methylmalonyl-CoA mutase is an enzyme involved in the breakdown of certain amino acid and fatty acids. Specifically, it catalyze the conversion of methylmalonyl-CoA. This reaction is crucial for energy production and the metabolism of fats and proteins. Vitamin B12 acts as a cofactor for methylmalonyl-CoA mutase, helping to facilitate this important step in energy metabolism.

Both of these enzymes are dependent on the presence of vitamin B12 to function effectively. A deficiency in vitamin B12 can impair the activity of these enzymes, leading to various health issues, including anemia, neurological problems, and disruptions in DNA synthesis and energy metabolism. Ensuring an adequate intake of vitamin B12 through dietary sources or supplements is essential for supporting the functions of these enzymes and maintaining overall health.

Deficiency Symptoms of Vitamin B12:-

A deficiency in vitamin B12 can lead to various symptoms and health issue. Since vitamin B12 is involved in crucial bodily functions, its deficiency can affect the blood, nervous system, and overall energy metabolism. Here are some common deficiency symptoms of vitamin B12 :

  1. Anemia : Vitamin B12 deficiency can lead to megaloblastic anemia, a condition characterized by the production of large, irregularly shaped red blood cells. Anemia can result in fatigue, weakness, and pale or jaundiced skin.
  2. Neurological Symptoms : B12 is essential for the health of the nervous system. Deficiency can lead to neurological problems such as:
    • Numbness or tingling in the hands and feet.
    • Difficult walking and balance problems.
    • Memory loss and cognitive difficulties.
    • Mood changes, including depression and irritability.
  3. Gastrointestinal Issues : B12 deficiency can lead to gastrointestinal problems, including :
    • Loss of appetite
    • Weight loss
    • Diarrhea or constipation
  4. Fatigue and Weakness : Since B12 is involved in energy metabolism, a deficiency can result in overall fatigue, weakness, and a lack of energy.
  5. Pernicious Anemia : This is a specific type of anemia caused by the body’s inability to absorb vitamin B12. It often involves an autoimmune response that attacks the stomach lining, where intrinsic factor ( a protein necessary for B12 absorption ) is produced.

It’s important to note that vitamin B12 deficiency can develop slowly over time, and symptoms may not be immediately apparent. Additionally, some individuals may be at a higher risk of B12 deficiency, including vegetarians and vegans (due to limited dietary sources ), older adults, individuals with pernicious anemia, and those with certain gastrointestinal conditions that affect B12 absorption.

If someone suspects a vitamin B12 deficiency, it’s crucial to consult with a healthcare professional for proper diagnosis and guidance on treatment, which may include dietary changes and B12 supplementation. Early detection and management are key to preventing complication associated with B12 deficiency.

How Vitamin B12 Help in RBCs Maturation :-

Vitamin B12 plays a crucial role in the maturation of red blood cells (RBCs) through its involvement in DNA synthesis and cell division. Here’s how vitamin B12 contributes to the process of RBC maturation :

  1. DNA Synthesis : Vitamin B12 is a cofactor for the enzyme called methionine synthase, which is involved in the conversion of homocysteine to methionine. This reaction is crucial for the synthesis of DNA. In the context of RBC maturation, DNA synthesis is essential during the early stages of RBC development in the bone marrow.
  2. Cell Division : RBCs originate from stem cells in the bone marrow, and their maturation involves several stages. One critical step is cell division, where the precursor cells divide and differentiate into mature red blood cells. Vitamin B12 is necessary for proper cell division, ensuring that the genetic material is accurately replicated and distributed to the new cells.
  3. Formation of Nucleotides : Vitamin B12 is involved in the synthesis of nucleotides, which are the building blocks of DNA. Adequate levels of B12 contribute to the availability of nucleotides needed for the replication and repair of DNA during RBC maturation.
  4. Prevention of Macrocytic Anemia : Vitamin B12 deficiency can lead to a type of anemia called megaloblastic or macrocytic anemia. In this condition, RBCs are larger than normal and have an irregular shape. This occurs because the DNA synthesis and cell division processes are impaired in the absence of sufficient B12, leading to immature and larger red blood cells.

In summary, vitamin B12 is essential for RBC maturation by facilitating DNA synthesis, cell division, and the formation of nucleotides. Without adequate B12, the normal development of red blood cells is compromised, leading to abnormalities their size and shape and potentially resulting in anemia.

Sources Of Vitamin B12 :-

Vitamin B12 is primarily found in animal products, and obtaining it through a well- balanced diet is essential, especially for individuals who follow vegetarian or vegan lifestyles. Here are some dietary sources of vitamin B12:

  1. Meat : Beef, pork, lamb, and other meats are rich sources of vitamin B12. Organ meats, such as liver and kidney, tend to have particularly high concentrations.
  2. Poultry : Chicken and turkey are good sources of vitamin B12. Dark meat, such as chicken thighs or turkey legs, generally contains more B12 than white meat.
  3. Fish : Fish, especially fatty fish salmon, trout, tuna, and sardines, are excellent sources of vitamin B12.
  4. Shellfish : Shellfish such as clams, oysters, mussels, and crabs are rich in vitamin B12.
  5. Eggs : Eggs, particularly the yolk, contain vitamin B12. However, it’s important to note that the B12 content in eggs is lower compared to some other animal products.
  6. Dairy Products : Milk, cheese, and yoghurt are good sources of vitamin B12. Many dairy products are also fortified with B12.
  7. Fortified Foods : Some plant-based foods, such as breakfast cereals, plant-based milk alternatives (like soy, almond, or rice milk), and nutritional yeast, are fortified with synthetic vitamin B12. Fortified foods can be essential for individuals who do not consume animal products.

It’s important to note that plants foods generally do not naturally contain significant amounts of vitamin B12 unless they are fortified. As such, individuals following vegetarian or vegan diets should pay special attention to their B12 intake and may need to rely on fortified foods or supplements.

Since vitamin B12 absorption is a complex process that involves intrinsic factor, a glycoprotein produced in the stomach, some individuals may have difficulty absorbing B12 efficiently. This includes older adults, individuals with pernicious anemia, or those with certain gastrointestinal conditions. In such cases, supplementation or injections with certain gastrointestinal conditions. In such cases, supplementation or injections may be necessary under the guidance of a healthcare professional to ensure adequate B12 levels.

Dosage Of Vitamin B12 :-

The recommended daily intake (RDI) for vitamin B12 for people over 14 is 2.4 micrograms (mcg).

However, you may want to take more or less, depending on your age, lifestyle, and specific situation.

Note that the percent of vitamin B12 your body can absorb from supplements is not very high- it’s estimated that your body only absorbs 10 mcg of a 500 mcg B12 supplements.

Here are some recommendations for B12 dosages for specific circumstances :-

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Which Form Of Vitamin B12 Should We Take ?

Methylcobalamin is the most bio-available type of Vitamin B12 which means the body absorbs it more easily. Naturally occurring, it is found in animal-based foods such as meat, fish, milk and eggs so methylcobalamin B12 is readily available in many people’s daily diets.

It is the most active form of Vitamin B12 and is used mainly in the liver, brain and nervous system.

Role Of Vitamin B12 In Tissue Repair :-

Some scientists like Seranno with their colleagues hypothesized that administering vitamin B12 during injury repair could help to promote cell plasticity. They used an animal model of acute ulcerative colitis to explore this, administering both vitamin B12 and OSKM transcription factors in separate experiments. “In this model, successful repair proceeds through natural reprogramming of epithelial cells to a more embryonic-like state,” they describe. “Remarkably, both OSKM and B12, resulted in significantly improved tissue recovery on day 14, as evaluated by blinded histological analysis, colon length and mucosal integrity.”

How Vitamin B12 is Absorbed In Our Gut ?

Vitamin B12, also known as cobalamin, is a water-soluble vitamin vitamin that plays a crucial role in various bodily functions, including the formation of red blood cells, neurological function, and DNA synthesis . Unlike many other vitamins, B12 is unique in that it is not synthesized by plants or animals but is produced by certain bacteria.

The absorption of vitamin B12 in our diet involves a complex process that primarily takes place in the stomach and small intestine. Here’s a simplified overview of the absorption process :

  1. Ingestion : Vitamin B12 is naturally found in various animal products, such as meat, fish, eggs, and dairy products. Individuals who follow a strict vegetarian or vegan diet may have a higher risk of B12 deficiency since plant-based foods generally do not contain significant amounts of the vitamin.
  2. Stomach acid and intrinsic factor : In the stomach, hydrochloric acid and pepsin help release vitamin B12 deficiency since plant-based foods generally do not contain significant amounts of the vitamin. The name of the intrinsic factor is Castle Intrinsic Factors (CIF).
  3. Binding to intrinsic factors : Vitamin B12 binds to intrinsic factor to form a complex. This B12-intrinsic factor complex is resistant to degradation by stomach acids.
  4. Travel through the digestive tract : The B12- intrinsic factor complex travels to the small intestine, where further digestion occurs.
  5. Absorption in the ileum : In the last part of the small intestine, called the ileum, there are specific receptors that recognize the B12-intrinsic factor complex. The complex binds to these receptors, and vitamin B12 is absorbed into the bloodstream.
  6. Transport to tissues : Once absorbed, vitamin B12 is transported in the blood, bound to a protein called transcobalamin. This complex carries B12 to various tissues throughout the body, where it is used for various cellular processes.

It’s important to note that certain conditions or factors can interfere with the absorption of vitamin B12. For example, individuals with pernicious anemia lack intrinsic factor or have impaired absorption in the ileum, leading to difficulties in B12 absorption. In such cases, B12 supplementation may be necessary. Additionally, aging and certain medications can affect B12 absorption. If you have concerns about your B12 status, it’s recommended to consult with a healthcare professional for guidance.

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