Vitamin B12 Deficiency – Symptoms, Risk Factors, and Prevention

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Vitamin B12 is a water-soluble vitamin also called as cobalamin. These vitamins are based on red meat and dairy products.

Deficiency in vitamin B12 can lead to neurological and haematological problems.

Vitamin B12 will be stored in the liver but it cannot be absorbed by the blood due to dietary insufficiency, malabsorption and lack of intrinsic factors. These conditions together lead to vitamin B12 deficiency.

Vitamin B12 deficiency can be caused due to three causes.

  • Malabsorption
  • Autoimmune
  • Dietary insufficiency


Parietal cells are acid-secreting cells. These cells can be found in the stomach wall. These cells are responsible for digestion and absorption of minerals and also maintains a healthy gut environment.

If a patient has a history of gastric bypass surgery, they would be at the risk of developing vitamin B12 deficiency. The new alimentary canal will bypass the intrinsic factor. The intrinsic factor is a protein that helps to absorb vitamin B12 in your intestine.

People affected by Crohn’s disease are prone to vitamin B12 absorption due to malabsorption. Other damage caused to the small intestine, like inflammation or infection with the tapeworm can also be a reason for vitamin B12 deficiency.


Pernicious anaemia is an autoimmune disease. The body produces antibodies and the anti-intrinsic factor antibodies bind and inhibits the effect of intrinsic factor.

As a result, there will be an inability of B12 to be absorbed by the terminal ileum.

Dietary Insufficiency

The liver is responsible to store the excess vitamin B12. The vitamin is based on animal and dairy products. So, for people who consume a vegan diet for approximately three years, there will be a deficiency in vitamin B12 due to a lack of dietary intake.

According to the National Library of Medicine titled Vitamin B12 deficiency people affected with anaemia are due to vitamin B12 deficiency. The percentage approximately ranges from 1-2%.

Food Sources of Vitamin B12

Food sources of Vitamin B12

The dietary vitamin B12 first binds to the protein called R-factor. The protein is secreted by the salivary glands. When the complex is formed and completed, the B12 is cleaved from the complex by the pancreatic enzymes.

The cleaved complex then binds to the glycoprotein called intrinsic factor. The intrinsic factor is secreted by the gastric parietal cells.

The fully formed complex binds to the receptors in the small intestine and absorption of vitamin B12 takes place.

The absorbed vitamin B12 is important for the haematological and neurological process. The absorption of dietary vitamins repeats and if there is any impairment it will lead to vitamin B12 deficiency.

The foods that are rich in vitamin B12 are listed below.


For every 100 grams of eggs, there is 1.1 µg of vitamin B12. The egg yolk contains more amount of vitamin B12 than the outer layer.

Eggs are also rich in vitamin D and they improve the absorption of vitamin B12. However, it is recommended to eat whole eggs to fully get their nutrients.


Fishes are rich in vitamin B12. Shellfish is a very good source of vitamin B12. Small fishes like herrings, sardines, salmons, trout and tuna are rich in vitamin B12 and omega 3 fatty acids.


The vitamin is originally based on animal food and red meat is an excellent source of vitamin B12. According to USDA, red meat contains about 0.6 µg of vitamin B12 for every 100 grams of meat.

Dairy Products

Dairy products provide you with a great source of vitamin B12. Cheese is one of the foods that provide vitamin B12.


Poultry is bred by humans for their nutrient source. Chicken is rich in vitamin B12. These animal-based foods enrich the body with various vitamins and proteins like vitamin B12 and lean protein.

Symptoms of Vitamin B12 Deficiency

The deficiency of vitamin B12 is called cobalamin deficiency. When your body has vitamin B12 deficiency, it indicates various signs and symptoms. The symptoms are listed below.


When you have vitamin B12 deficiency, weakness will be a common symptom. You will feel very tired most of the time even without doing any work.

When you have reduced red blood cell production, your body will feel very tired and weak. As a result, you feel weak most of the time.

Heart palpitations

Heart palpitations are irregular heartbeats. Your heart tends to beat fast. This may be due to stress or medication.

Heart palpitation can affect your quality of life but still, they are harmless most of the time.

Pale skin

Anaemia caused due to vitamin B12 deficiency is the reason for pale skin. There will be fewer or no fully-matured healthy red blood cells. This causes pale skin.

A smooth tongue

A smooth tongue may be caused due to various nutritional deficiencies like folate, iron and vitamin B12 deficiency.

When you have these deficiencies, your tongue becomes sore and red in colour. Vitamin B12 deficiency causes your tongue to swell and as a result, your tongue might appear smooth.


People with vitamin B12 deficiency have symptoms like weakness, fatigue and constipation. You also tend to lose your appetite, as a result of which you lose weight.

Vitamin B12 is a water-soluble vitamin and if there is a deficiency it can cause constipation.

Nerve problems

Vitamin B12 is a vital nutrient for neurological and psychological functions. When there is a deficiency of vitamin B12 in your body it leads to nerve problems and also difficulty in thinking.

Vision loss

Vitamin B12 deficiency can lead to progressive, bilateral and painless vision loss.

Mental problems

Vitamin B12 deficiency can result in psychiatric problems. The deficiency can lead to depression, memory loss and change in personality.

Benefits of Vitamin B12 Deficiency

Vitamin B12 is an essential vitamin for the body. The body absorbs the vitamin through foods like red meat, eggs and dairy products. Vitamin B12 is required for the body for various function and are listed below.

Blood Health

Vitamin B12 is required for blood formation. Vitamin B12 deficiency causes anaemia. Low levels of vitamin B12 can lead to the irregular formation of blood cells which causes megaloblastic anaemia.

Anaemia can lead to low levels of oxygen transportation which can make you weak.

Vitamin B12 absorbed by the blood is used as a cofactor for the synthesis of DNA, myelin and fatty acids. The excess vitamin B12 is stored in the liver to avoid any deficiency.

When vitamin B12 cannot be absorbed due to various reasons like malabsorption and dietary insufficiency it leads to a deficiency.

Brain Health

Vitamin B12 keeps your brain healthy. Vitamin deficiency is related to memory loss and brain atrophy.

Atrophy is the condition where there is a loss of neurons and it will be difficult to communicate between themself. This might lead to various health conditions like memory loss and dementia.

Pregnant women require vitamin B12 as it is important for the development of the foetus’s brain. Vitamin deficiency may lead to neural tube defects in pregnant women and can also lead to miscarriage and premature birth.

Skin Health

Vitamin B12 deficiency can cause dryness and acne. In extreme cases, it can lead to psoriasis and eczema. The vitamin helps to reduce inflammation in the skin and improves cell reproduction.

Foods like eggs, dairy and fish promote skin health.

Heart Health

Many research suggests that B vitamins reduce the risk of heart diseases. Cobalamin when combined with folate can prevent all diseases related to the heart and blood vessels.

Risk Factors of Vitamin B12 Deficiency

Vitamin B12 deficiency can lead to anaemia and also reduces the healthy red blood cells. Vitamins plays an important role to produce healthy red blood cells and these cells carry oxygen throughout the body.

So when there is a deficiency in vitamin B12 you might feel weak and fatigued. These symptoms may also indicate that you are anaemic.

A family history of the disease

Vitamin B12 deficiency tends to run in genes. The deficiency is common among people aged 60.

If you have any autoimmune disease like Celiac disease the deficiency may aggravate the condition. Vitamin deficiency commonly affects women more than men. It causes anaemia in women.

Having part or all of your stomach or intestine removed

The stomach contains many enzymes that help in digestion and regulates bowel movement.

When a part of your stomach or intestine is removed by surgical methods. This method is called gastrectomy and the ability to absorb vitamin B12 reduces. This causes a deficiency in vitamin B12.

There will be excess vitamin B12 stored in the liver but the body will not be able to use it.

Autoimmune diseases, including type 1 diabetes

Autoimmunity is a condition, where your cells destroy your own cells. Some of the common autoimmune diseases are type 1 diabetes, Alzheimer’s disease, Addison’s disease and arthritis.

People with type 1 diabetes will have vitamin B12 deficiency. Type 1 diabetes occurs due to the destruction of insulin-secreting beta cells. It increases the risk of vitamin B12 deficiency.

Crohn’s disease

Crohn’s disease is an inflammatory bowel syndrome. The disease causes inflammation in the digestive tract, abdominal pain, diarrhoea, fatigue, malnutrition and weight loss.

The disease spreads to other areas of the stomach. Crohn’s disease can have painful symptoms and can be sometimes life-threatening. There is no cure for Crohn’s disease.

The risk factor of vitamin B12 deficiency increases with people affected by Crohn’s disease. The disease often involves terminal ileum.


Some people affected by HIV/AIDS have vitamin B12 deficiency. Vitamin B12 deficiency is related to neurological and neuropsychiatric diseases.

Lower levels of cobalamin and folic acid are commonly seen in patients with HIV.

Some medicines

Vitamin B12 Tablets

Medications that treat gastrointestinal diseases can cause a deficiency in vitamin B12.

The gastric juices are required to absorb vitamin B12. These medications suppress gastric juices with proton inhibitors.

Strict vegetarian diets

Vitamin B12 is a water-soluble vitamin and is derived from animal food. Foods like red meat are rich in vitamin B12 and strict vegetarians avoid animal foods. This results in vitamin B12 deficiency.

Research suggests that even people who consume dairy products are also at the risk of getting affected by vitamin B12 deficiency.

Being an older adult

Aged people have problems related to malnutrition. So, absorption of vitamin B12 will be very low and hence there will be deficiency in vitamin absorption.

Prevention of Vitamin B12 deficiency

Vitamin B12 deficiency may be caused due to malabsorption or due to low consumption of nutrient-rich food. People who follow a strict vegetarian diet are also prone to vitamin B12 deficiency.

There are a few tips suggested to avoid vitamin B12 deficiency.

  • Consume animal food products like red meat, fish, eggs and milk. Animal-based food products are rich in vitamin B12 and they prevent you from getting deficient.
  • Fortified foods like cereals have added nutrients that will help to nourish your body with the required nutrients. These cereals will be rich in iron and vitamin B12. They will help in the absorption of the nutrients and prevent any kind of malabsorption.
  • Vitamin supplements will help with the absorption of the vitamin. These supplements will give you nutrients your body requires apart from your dietary nutrients. Before consuming any supplements always consult your doctor.
  • In patients with gastric bypass surgery B12 supplementation will be very much helpful.
  • Consumption of alcohol is also related to vitamin B12 deficiency. So, avoid the habit of excessive alcohol consumption and smoking.


If you experience any symptoms of vitamin B12 deficiency consult your doctor immediately and do not take any symptoms lightly. They may indicate significant medical health conditions.

Women are more likely to be affected by vitamin deficiency than men. There can be many underlying reasons. Consume foods that are rich in iron and nutrients to avoid getting anaemic.

If you have any major symptoms get a complete blood test and consult your doctor.


What are the signs of vitamin B12 deficiency?

There are some common symptoms that indicate vitamin B12 deficiency. They are pale skin, heart palpitations, smooth tongue, mouth ulcers, vision loss and mental illness.

Does vitamin B12 make your hair grow?

Vitamins like B12, D, biotin and iron promote hair growth. Deficiency in these nutrients may cause problems related to hair.

Why is vitamin B12 necessary for the body?

Vitamin B12 is important for neurological and haematological functions. Deficiency in vitamin B12 causes impairment in red blood cell formation.

How much vitamin B12 is required regularly?

According to USDA, the recommended dietary allowance is 2.4 mcg on a daily basis.

What happens when you start taking B12?

Vitamin B12 is required for the proper functioning of blood and nerve cells. These vitamins are also required for the proper functioning of the genetic materials.

Can you take B12 any time of day?

Vitamin B12 is a water-soluble vitamin that can be taken at any time during the day. It is more beneficial to the body when taken in the morning.

How is vitamin B12 deficiency treated?

Vitamin B12 causes anaemia and is treated by directly injecting vitamin B12 into your veins.

What tests are suggested for Vitamin B12 deficiency?

 The test suggested for vitamin B12 deficiency is complete blood count (CBC), Schilling test, methylmalonic acid (MMA) and vitamin B12 level.


The Information including but not limited to text, graphics, images and other material contained on this blog are intended for education and awareness only. No material on this blog is intended to be a substitute for professional medical help including diagnosis or treatment. It is always advisable to consult medical professional before relying on the content. Neither the Author nor Star Health and Allied Insurance Co. Ltd accepts any responsibility for any potential risk to any visitor/reader.

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