ID: 260
Category: Nutrition
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createdon: 05 Jun 2023
updatedon: 05 Jun 2023

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Author: Khoa Tran
Published Jun 05, 2023
Updated Jun 05, 2023

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Vitamin B12 Deficiency

Etymology and Pronunciation

vitamin (vahy-tuh-min)
vita - Latin for "life"
amine - Refers to a class of organic compounds that contains amino acids.

deficiency (dih-fi-shuh n-see)
deficiens - Latin for "failing" or "lacking"

History of Vitamin B12 Deficiency

In the early 19th century, clinical reports and studies on patients with pernicious anemia paved the way for significant advancements in understanding this condition. The observations and insights gained from these studies provided a foundation for further research. Scientists, eager to unravel the mysteries surrounding pernicious anemia, recognized that inadequate nutrient intake might be at the root of the problem.

Several decades later, the isolation of vitamin B(12) occurred simultaneously by two research groups. This milestone achievement was followed by the crystallization and characterization of the vitamin in Dorothy Hodgkin's laboratory, leading to her Nobel Prize in 1964. These groundbreaking accomplishments unraveled the true nature of vitamin B(12) and its intricate relationship with intrinsic factor.

The discovery was made possible by various technologies. Researchers utilized the microscope to observe the deficiency's cellular-level effects, leading to a better understanding of the condition's underlying mechanisms. Additionally, the spectroscope facilitated the analysis of the nutrient's chemical composition, while x-ray crystallography played a crucial role in determining the intricate molecular structure of the vitamin.

We now know that this deficiency could lead to a debilitating neuropathy, often resulting in paralysis and even death. Post mortem analyses further revealed the demyelination of the spinal cord as a consequence of vitamin B(12) deficiency.

Modern Understanding of Vitamin B12 Deficiency

Vitamin B12 is an important nutrient that our bodies need in order to function properly. It helps our bodies make red blood cells, it keeps our nervous system healthy, and it helps us to have enough energy to get through the day. 

However, some people don't get enough vitamin B12 in their diets or have trouble absorbing it from the foods they eat. This can lead to a condition called vitamin B12 deficiency. 

People who have vitamin B12 deficiency may feel tired or weak, they may have trouble thinking clearly or remembering things, and they may have tingling or numbness in their hands and feet. In some cases, people with severe vitamin B12 deficiency may develop anemia, which is a condition where their body doesn't have enough red blood cells to carry oxygen around their body. 

If you think you might have a vitamin B12 deficiency, it's important to talk to your doctor. They can run some tests to see if you have low levels of vitamin B12 in your blood, and they can help you figure out the best way to get more of this important nutrient. 

In general, foods that are high in vitamin B12 include meat, fish, and dairy products. Some people may also need to take vitamin B12 supplements in order to keep their levels up. 

While vitamin B12 deficiency can be a serious condition if left untreated, it's important to remember that it's also very treatable. By working with your doctor and making some changes to your diet or taking supplements, you can make sure that your body is getting all of the vitamin B12 it needs to stay healthy and strong.

Causes of Vitamin B12 Deficiency

- Inadequate dietary intake: Vitamin B12 is mainly found in animal-based foods such as meat, fish, dairy products, and eggs. A strict vegetarian or vegan diet that excludes these food sources can lead to a deficiency if not supplemented adequately.
- Malabsorption issues: Some medical conditions can interfere with the absorption of vitamin B12 from the food you eat. These conditions include pernicious anemia, celiac disease, Crohn's disease, bacterial overgrowth in the small intestine, and surgical removal of the part of the intestine responsible for absorption (e.g., gastric bypass surgery).
- Lack of intrinsic factor: Intrinsic factor is a protein produced by the stomach that binds to vitamin B12 and allows its absorption in the intestines. Conditions such as pernicious anemia, an autoimmune disorder, can lead to a lack of intrinsic factor, resulting in poor absorption of vitamin B12.
- Aging: As people age, their ability to absorb vitamin B12 decreases. This is due to decreased production of stomach acid and intrinsic factor, as well as changes in the gastrointestinal tract.
- Medications: Certain medications can interfere with vitamin B12 absorption or increase its excretion. Examples include proton pump inhibitors (PPIs), histamine-2 receptor antagonists (H2 blockers), metformin (used to treat diabetes), and some anticonvulsant medications.
- Gastrointestinal surgeries: Surgical procedures that involve the removal or bypass of parts of the stomach or small intestine, such as weight loss surgeries, can reduce the absorption of vitamin B12.
- Chronic alcoholism: Excessive alcohol consumption can interfere with the absorption and utilization of vitamin B12 in the body.

Treatments for Vitamin B12 Deficiency

Vitamin B12 deficiency can be treated through dietary changes, supplements, or injections. 

If the deficiency is caused by lack of Vitamin B12 in the diet, then it's usually resolved through alterations in food choices. Foods high in vitamin B12 include meat, fish, dairy products, and fortified cereals. Eating more of these products can help increase the levels of Vitamin B12 in the body.

However, if the deficiency is caused by an absorption problem, such as pernicious anemia or Crohn's disease, supplements or injections are required. Vitamin B12 supplements are available in tablet or liquid form and can be taken orally. Injections are also an option, and they are taken either by a health professional in a doctor's office or self-administered at home.

The treatment process will depend on the severity of the deficiency, the individual's overall health, and the underlying cause of the deficiency. Therefore it is crucial to consult with a healthcare professional before starting any Vitamin B12 treatments.

Nutrional Changes

- Include animal-based foods: Animal-based foods are the richest sources of vitamin B12. Include foods such as meat (beef, pork, lamb), poultry (chicken, turkey), fish (salmon, trout, tuna), shellfish (clams, oysters), dairy products (milk, cheese, yogurt), and eggs in your diet.
- Fortified foods: Some plant-based foods, such as fortified cereals, plant-based milk alternatives (soy milk, almond milk), and nutritional yeast, are fortified with vitamin B12. Check the labels to ensure they contain adequate amounts of vitamin B12.
- Consider B12 supplements: If you follow a strict vegetarian or vegan diet or have conditions that affect vitamin B12 absorption, consider taking vitamin B12 supplements. These supplements are available in various forms, including pills, sublingual tablets, and injections. Consult a healthcare professional to determine the appropriate dosage and form of supplementation for your needs.
- Consume fermented foods: Fermented foods like tempeh, miso, and certain types of yogurt may contain small amounts of vitamin B12. While they may not be sufficient as the sole source of vitamin B12, they can contribute to overall intake.
- Eat nutritional yeast: Nutritional yeast is a deactivated yeast often used as a cheese substitute. It is a good source of vitamin B12, especially for vegans. Sprinkle it on your salads, popcorn, or incorporate it into recipes for added flavor and nutrients.
- Be cautious with seaweed and algae: Some types of seaweed and algae, such as nori and spirulina, are often touted as sources of vitamin B12. However, they contain forms of B12 that are not well absorbed by the human body, so they should not be relied upon as the primary source of vitamin B12.


Anemia (low red blood cell count)
Mouth sores
Numbness in fingers and toes
Muscle Weakness

Confirmation Tests

- Blood test (for Vitamin B12)
- Complete blood count
- Homocysteine test
- Methylmalonic acid (MMA) test
- Schilling test