Vitamin B12 Deficiency: Causes, Symptoms and Treatment

Vitamin B 12 deficiency is more prevalent in regions of world with higher percentage of vegetarians, vegans and aging population – WHO Study

You may have Vitamin B12 Deficiency if you are suffering from extreme undefinable tiredness and lethargy, mood swings, depression, ringing feeling in ears (tinnitus), pigmentation, light headed, if you sweat excessively (Hyperhidrosis) or if you are a vegetarian or a vegan. Read on…


Why is B12 so important?

Vitamin B 12 or Cobalamin is a very important micronutrient required for proper functioning of nervous system, formation of erythrocytes, formation of myelin sheath and DNA and crucial for regulating our metabolism, weight management and immune system.

Vitamin B12 also facilitates absorption of folic acid, facilitating healthy nervous system and release of energy. The normal requirement of vitamin B12 for adults is 2.4micrograms/day. Vitamin B12 deficiency is very common, especially in elderly.

According to the National Health and Nutritional examination Survey, 3.2% of adults above age 50 have significant vitamin B12 deficiency, while 20% have borderline deficiency.


Vitamin B12 Deficiency symptoms

It may take a few years for Vitamin B 12 Deficiency symptoms to manifest. With mild deficiency you may not posses any discernible clinical features BUT If the deficiency persists for a prolonged period of time, neurological symptoms may come into picture. If not checked in time, Vit B12 Deficiency may lead to complications like…

  • Pale skin.
  • Exhaustion.
  • Mouth sores.
  • Loss of appetite.
  • Swollen tongue.
  • Nausea, vomiting.
  • Constipation/diarrhoea.
  • Palpitations and Dyspnea.
  • Abnormal bloating and gas.
  • Ringing feeling in ears (tinnitus)
  • Excessive Sweating (Hyperhidrosis)
  • Unexplainable constant feeling of Fatigue.
  • Unexplainable Mood swings and Depression
  • Pernicious anemia, by affecting production of RBCs.

Prolonged deficiency of Vitamin B12 can lead to Neuropsychiatric disorders ranging from Neuropathy to Dementia, with the patient may develop following signs and symptoms…

  • Myelopathy.
  • Memory decline.
  • Motor weakness.
  • Abnormal reflexes.
  • Gait abnormalities.
  • Erectile dysfunction.
  • Sub acute combined degeneration.
  • Dementia (Neuropsychiatric Diseases and treatment 2010).
  • Sensory disturbances including paraesthesias, tingling and numbness.
  • Multiple Sclerosis (International Journal of Preventive Medicine 2012).
  • Brain shrinkage and Neurodegenerative disorders like Parkinson’s disease and Alzheimer’s disease.

The above mentioned Neurological problems are described by various mechanisms…

1. Vitamin B 12 regulates synthesis and maintenance of Myelin Sheath (covering of nerve cells), responsible for protection of neuron and transmission of nerve impulses. Reduced level of vitaminB12 may lead to demyelination of nerve cells leading to axonal damage.

2. Reduced levels of Vitamin B12 is associated with altered production of neurotransmitters and elevated levels of homocysteine and methylmalonic acid (MMA).

3. Elevated levels of homocysteine leads to brain atrophy and other vascular complications, neurobiology of aging 2014.


What can cause Vitamin B 12 deficiency?
1 :: Decreased absorption of vitamin B12 from stomach and intestine, due to…
  • Nitrous oxide abuse.
  • An autoimmune disease like lupus, grave’s disease etc.
  • Certain medications like Metformin, used by Diabetics.
  • Elderly individuals, because to gradual loss of gastric acid.
  • Prolonged use of oral contraceptives, affects vitamin B 12 absorption.
  • Chronic alcoholism, by impairing liver functions and depleting vitamin B 12 stores.
  • Long term use of gastric acid suppressing medications; gastric acid help absorb Vitamin B 12.
  • Pernicious anemia, damages cells that produces intrinsic factor, responsible for absorption of vitamin B12 in intestines.
  • Surgical removal of a part of stomach or intestines or patients with short bowel syndrome, affects vitamin B12 absorption.
  • Ailments of pancreas and small intestines like inflammation of pancreas, Crohn’s disease, celiac disease, bacterial and parasitic infections.
  • Atrophic gastritis, can cause low gastric PH which increases bacterial growth in upper intestine leading to mal absorption of protein-bound vitamin B12.
2 :: Decreased Vitamin B12 intake…
  • Malnutrition.
  • Babies born to vegetarian mothers who didn’t take adequate amount of vitaminB12 during pregnancy.
  • Vegetarians or Vegans in particular are at risk of developing deficiency of vitamin B12, as vitamin B12 occurs naturally in animal products only.
3 :: Increased Vitamin B12 requirements…
  • AIDS/HIV positive individuals.
  • People with rapid red blood cell breakdown. British Medical Journal, 2014.


Diagnosis of Vitamin B 12 deficiency

Given the array of symptoms it can cause, differential diagnosis to establish Vitamin B12 deficiency is extremely important. Some of the tests used in diagnosis are

  • RBC count.
  • Intrinsic factor antibody levels.
  • Serum homocysteine and Methylmalonic acid levels (elevated).
  • Serum B12 levels (generally low), further examination is warranted, if symptoms of B12 deficiency persists with normal B12 levels.

Other procedures

  • Enteroscopy to examine the small intestine.
  • Esophagogastroduodenoscopy (EGD) to examine the stomach.
  • Bone marrow biopsy to rule out erythrocytes abnormalities or anemia.


Treatment of Vitamin B 12 Deficiency

1 :: Vitamin B12 supplementation Severe deficiency can be treated by giving supplementation, which can be given as:

  • Weekly shot.
  • Daily high dose.

Supplementation by pill or injection appears to be very effective in treating deficiency, irrespective of the cause. Large doses given by mouth don’t rely on the presence of intrinsic factor or intact intestine for absorption. Dosage as high as 1-2mg/day can even treat pernicious anaemia.

2 :: Vitamin B12 rich food According to National Institute of Health, beef liver and clams are top sources of B12. Other sources are:

  • Trout.
  • Turkey.
  • Salmon.
  • Oysters.
  • Chicken.
  • Spirulina.
  • Corn Flakes.
  • Dairy products.
  • Fortified cereals.
  • Nutritional yeasts.
  • Cereals and pulses.
  • Fortified Soya Milk.

According to Institute of Medicine people above 50 should take B12 supplement, as they may not be able to absorb enough vitamins from food sources.


Most of the people respond well with the above-mentioned treatment except those who develop permanent nerve damage or patients with neurodegenerative disorder like Alzheimer’s disease, have not shown any improvement in cognitive functioning even at high doses.

So, it’s best to get enough Vitamin B12 to prevent its deficiency but if occurs; a timely supplementation of this ‘Nervous Vitamin’ is required to prevent permanent damage to nervous system.
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