Vitamin B12

Vitamin B12
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Vitamin B12 is a very important B vitamin. It is essential for nerve tissue health, brain function, and the production of red blood cells. Cobalamin is another name for vitamin B-12.

Deficiency can occur when vitamin B-12 levels are too low. This can lead to irreversible neurological symptoms. In the United States (USA), 1.5 to 15 percent of the population is currently diagnosed with vitamin B-12 deficiency.

This article will explore the functions of vitamin B-12, how to know when a person is not consuming enough vitamin B-12, and where to get more resources.

Fast facts on vitamin B-12

Vitamin B-12 is important for the synthesis of red blood cells for brain function.

Vitamin B-12 deficiency can cause neurological difficulties and anemia.

People over the age of 14 should consume more than 2.4 micrograms (mcg) of vitamin B-12 daily.

Vitamin B-12 is naturally found in meats, but people who don’t eat meat like vegans can take vitamin B-12 in supplement form.

What is Vitamin B12?

Vitamin B-12 is a water-soluble vitamin like all other B vitamins.

This means it can dissolve in water and pass through the bloodstream. The human body can store vitamin B-12 for up to four years. Excess or unwanted vitamin B-12 is excreted in the urine.

Vitamin B-12 is structurally the most complex and largest vitamin. It occurs naturally in meat products and can only be produced industrially through bacterial fermentation synthesis.


Vitamin B-12 occurs naturally in animal products such as fish, meat, eggs, and dairy products. It is not typically seen in plant foods.

Good dietary sources of vitamin B-12 include:

  • Beef
  • Pork
  • Ham
  • Poultry
  • Lamb
  • Fish, especially haddock and tuna
  • Dairy products such as milk, cheese, and yogurt
  • Some nutritional yeast products
  • Eggs

Some types of soy milk and breakfast cereals are fortified with vitamin B-12.

It is always better to maintain a balanced diet and get a healthy amount of nutrients before active treatment is required. Deficiency symptoms are easily avoided by a healthy diet.


Vitamin B-12 is essential for the normal function of the brain and nervous system. It also plays a role in the formation of red blood cells and helps create and regulate DNA.

The metabolism of every cell in the body depends on vitamin B-12 as it plays a role in the synthesis of fatty acids and energy production. Vitamin B-12 helps the human body absorb folic acid, releasing energy.

The human body produces millions of red blood cells every minute. These cells cannot reproduce properly without vitamin B-12. If vitamin B-12 levels are too low, the production of red blood cells is reduced. Anemia can occur if the red blood cell count drops.

Entry requirements

In the US, the National Institutes of Health (NIH) recommend that teens and adults over the age of 14 consume 2.4 micrograms (mcg) of vitamin B-12 per day. Pregnant women should consume 2.6 mcg and breastfeeding women should consume 2.8 mcg.

Excessive vitamin B12 intake did not show toxic or harmful qualities. However, people are always advised to speak to their doctor before starting supplements.

Some medications can interact with vitamin B12. These include metformin, proton pump inhibitors, and h2 receptor agonists, often used for peptic ulcer disease. All of these drugs can interfere with vitamin B-12 absorption. The antibiotic chloramphenicol or chloromycetin can also interact with red blood cell production in humans by taking supplements.

Deficiency symptoms

Vitamin B12 deficiency occurs when the body does not get enough vitamin B-12.

It can cause irreversible and potentially serious damage, especially to the nervous system and brain.

Even slightly lower than normal vitamin B-12 levels can trigger deficiency symptoms such as depression, confusion, memory problems and fatigue. However, these symptoms alone are not specific enough to diagnose vitamin B-12 deficiency.

Other symptoms of vitamin B12 deficiency include constipation, loss of appetite, and weight loss.

When symptoms increase, they can include neurological changes such as numbness and tingling in the hands and feet. Some people may have trouble maintaining balance.

Babies with vitamin B12 deficiency may show unusual movements such as facial tremors, such as reflex issues, feeding difficulties, irritation, and eventual growth issues if the deficiency is not treated.

Vitamin B12 deficiency poses a serious risk of permanent nerve and brain damage. Some people with insufficient vitamin B-12 have a higher risk of developing psychosis, mania, and dementia.

Insufficient vitamin B-12 can also cause anemia. The most common symptoms of anemia are fatigue, shortness of breath, and irregular heartbeat.

People with anemia may also experience:

  • Aching mouth or tongue
  • Weight loss
  • Pale or yellowed skin
  • Diarrhea
  • Menstrual problems

Vitamin B12 deficiency also makes people more susceptible to the effects of infections.

Who is at risk?

Vegans are at risk of vitamin B-12 deficiency, as there are no animal-sourced food products in their diets. Pregnancy and breastfeeding can make deficiency worse in vegans. Plant-based foods do not have enough cobalamin to guarantee long-term health.

People with pernicious anemia may be deficient in vitamin B-12. Pernicious anemia is an autoimmune disease that affects the blood. Patients with this disorder do not have enough internal factor (IF) in the stomach, a protein that allows the body to absorb vitamin B-12.

Other at-risk groups include people with small bowel problems, such as an individual whose small intestine has been surgically shortened. They may not be able to absorb cobalamin properly. People with Crohn’s disease are said to be at risk, but researchers maintain that there is a lack of evidence to confirm.

Gastritis, celiac disease, and inflammatory bowel disease can cause deficiency because these conditions result in reduced absorption of nutrients.

People with chronic alcoholism can also suffer from vitamin B-12 deficiency as their bodies cannot absorb nutrients efficiently.

People treating diabetes with metformin are advised to monitor their vitamin B-12 levels. Metformin can reduce the absorption of vitamin B-12.

Treatment includes vitamin B-12 injections. People who have problems with nutrient absorption should be injected with vitamin B-12.


Some people have difficulty absorbing vitamin B-12 from food sources and may need supplements.

This includes older adults, patients with pernicious anemia, and those with achlorhydria or bowel disorders. There may be problems with absorption of vitamin B-12 from foods.

Supplements can be taken by mouth or with a nasal spray. However, oral supplements do not help in many deficiency situations. In these cases, vitamin B-12 can be injected.

Because the vegan diet naturally eliminates meat products that provide B-12, vegans can take nutritional supplements to prevent deficiency. This is especially important during pregnancy and breastfeeding.

A variety of B-12 supplements are available for purchase at health food stores and online.

Side effects

The side effects of taking vitamin B-12 are very limited. High amounts are not considered to be toxic, and even 1000 mcg doses are not considered harmful.

No adverse reaction to B-12 has been reported since 2001, when a person in Germany reported rosacea as a result of B-12 supplementation. Cases of acne triggered by B-12 have also been reported.

Cyanocobalamin is an injectable form of the supplement containing residues of cyanide, a toxic substance. As a result, some concerns arose about its possible effects. However, many fruits and vegetables contain these traces and are not considered a significant health risk.

However, this type of supplement is not recommended for people with kidney disease.

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