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6 Ways a Vitamin B12 Deficiency Can Affect the Body

The human body has an impressive ability to absorb and store vitamins and minerals. Unfortunately, there are times when certain lifestyle or diet choices lead to nutrient deficiencies that can cause a host of health problems.


The truth is that a large number of Indians suffer from vitamin B12 deficiencies causing several surprising and unexpected symptoms. Vitamin B12 (Cobalamin) is a part of the B vitamin family which consists of a group of eight vitamins that are essential in maintaining good health and feeling energised. Since this group of vitamins is water soluble and eliminated from the body on a daily basis, they must be restored regularly. Interestingly, each individual B vitamin performs unique functions in the body and is supplied by different kinds of foods.

Quick Facts About Vitamin B12:


  • Vitamin B12 plays an important role in the production of red blood cells. It helps to create and regulate DNA, and aids in the function of brain cells.
  • Your body does not produce Vitamin B12 naturally.
  •  Vitamin B12 is the largest and most structurally complex vitamin.
  •  Vitamin B12 is naturally available in animals and it can only be industrially produced via bacterial fermentation-synthesis.
  • Vegetarians can rely on dairy products, eggs, and certain fortified foods as a source of B12.  

What is the right amount of B12 to consume on a daily basis?


How much B12 you need depends on your age, medical conditions you may have, or your eating habits. Here is a list of daily recommended average consumption in micrograms (mcg):

  • 9-13 year-old children: 1.8 mcg
  • 14-18 year-old teens: 2.4 mcg
  • Adults: 2.4 mcg (2.6 mcg per day if pregnant and 2.8 mcg per day if breastfeeding)


How Does A Vitamin B12 Deficiency Impact your Body?


  • Lack of energy and fatigue
    Vitamin B12 is often nicknamed the ‘Energy Vitamin’ because a deficiency can lead to weakness, confusion and lethargy. This occurs when your body doesn’t have enough B12 for the production of red blood cells that transport oxygen throughout your body.

    These symptoms are often attributed to general tiredness or a myriad of other health problems, as a result of which people don’t think of getting tested for a vitamin B12 deficiency. However, if you have been experiencing fatigue and a lack of energy for weeks, along with signs of impaired thinking then it may be wise to consult a doctor.

  • Lightheadedness and Breathlessness
    A vitamin B12 deficiency can cause anaemia due to the lack of red blood cells in the body resulting in dizziness, and shortness of breath. These symptoms may become prominent when you exert yourself (even slightly). However, since a number of other health issues can also lead to breathlessness and dizziness, it is advisable to consult a doctor before jumping to conclusions.
  • Inflammation of Tongue and Mouth Ulcers
    Medically, an inflammation of tongue is called Glossitis. In this condition, the tongue changes colour and shape with signs of redness, swelling and pain. The tongue looks smooth as the tiny bumps that contain taste buds disappear. This condition can impact the way you eat and speak. This is usually an early sign of a Vitamin B12 deficiency.

    Mouth ulcers, feelings of pins and needles in the tongue, or an itching sensation in the mouth may also occur as a result of a vitamin B12 deficiency.
  • Blurred Vision
    Disturbed or blurred vision can also occur as a result of a Vitamin B12 deficiency. This happens when the deficiency causes damage to the optic nerve that leads to your eyes. The nervous signal that travels from the eye to the brain is disturbed due to this damage, leading to impaired vision. This condition is called optic neuropathy and treatment involving B12 supplements usually reverses the impairment.
  • Depression
    A deficiency in Vitamin B12 has been linked to certain mood changes including typical signs of depression. The “homocysteine hypothesis of depression” explains the connection between mood changes associated with depression and a B12 deficiency. The hypothesis states that high levels of homocysteine caused by low levels of B12 can lead to the damage of brain tissue and disturb signals to and from the brain. It can also lead to neurotransmitter deficiency (chemical substances in the brain that control emotions), which causes depression of mood. Taking a supplement or having B12 rich foods may help elevate your mood. However, it is important to note that depression has a number of other causes that a doctor can assess and diagnose.
  • Nerve Damage or Uncomfortable Tingling
    One severe side effect of a long-term Vitamin B12 deficiency is a condition called Paresthesia. Here, a person experiences a prickling sensation in the hands and feet. This happens because Vitamin B12 plays an important role in the production of a fatty substance called myelin which protects and insulates your nerves. In the absence of B12, myelin production is disrupted and this impacts the nervous system. Since uncomfortable tingling can be a result of other health conditions as well, this symptom should not be taken in isolation when considering a B12 deficiency.

Who is at risk of developing a B12 deficiency?



People who follow a vegan or vegetarian diet are at a higher risk as their diet may be based entirely on plants - including grains, nuts, vegetables or fruits.

Those who suffer from pernicious anaemia - an autoimmune disease that influences the blood are at a higher risk of developing a B12 deficiency.

Additionally, Crohn’s disease, gastritis, inflammatory bowel disease or small intestinal problems interfere with the normal absorption of B12. Also, medications that help to reduce indigestion (acidity) can result in B12 deficiency because acid is needed to absorb B12. Older people are more likely to have deficiencies as a result of a reduction in stomach acid production. The good news is that in most cases, Vitamin B12 deficiencies can be easily reversed via supplements prescribed by a doctor.

Dr. Prabhat Kumar Jha
Internal Medicine
Meet The Doctor
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