Vitamin B-12 Deficiency: Symptoms and Causes

Vitamin B-12 Deficiency: Symptoms and Causes

Also known as cobalamin, vitamin B-12 is one of the 8 B water-soluble vitamins and unessential nutrient in the B-complex.  You can get this nutrient by consuming animal foods but you should also consider supplements for a better intake.  Vitamin B12 is a complex vitamin that has a very important role in human health.

It keeps the metabolism healthy and has an important role in supporting brain function. It helps in red blood cell formation, keeps the marrow healthy and regulates the DNA.

This vitamin cannot be produced by plants animals or fungi.  It will only be produced by a bacterium. A daily recommended intake for humans of vitamin B12 is 2-3 micrograms/mcg up to 4-7 micrograms/mcg per day.

But absorption will allow only 1.5 mcg of B-12 per meal, so it is recommended to also take a supplement.

Deficiency of vitamin B12

This vitamin can be stored inside a human body for 3 to 4 years.  Only after this much time will a person see he’s deficient in B12. A common blood test will show if a person has a deficiency of B12.

An optimal range is 180-400 ng/L, while a low level will get to 180-400 ng/L. Symptoms will start at lower levels: 150-180 ng/L.

Older adults might also have symptoms when they reach a level between 200 and 500 pg/mL.

Stages of Deficiency

  1. Blood levels and cell stores will decline.
  2. A person will experience low cellular levels
  3. They will be B12 in balance that will cause an increase and homocysteine/MMA and will decrease the rate of DNA synthesis.
  4. The last stage will show signs of macrocytic anemia, peripheral neuropathy and other neurological disorders.  There will be some other symptoms that are usually attributed to old age: loss of mobility, balance, or memory.  A long-term deficiency will cause irreversible damage in the case of neurological symptoms.

What causes deficiency in vitamin B12

First of all, vitamin B12 is only consumed through animal foods or supplements.  The deficiency can be caused by a poor diet or some different health issues like gastritis, stomach surgeries or other factors that impair the absorption of vitamin B12. The stomach might also have low hydrochloric acid.

Other causes involve parasitic infections (like Giardia), genetic factors, a high consumption of alcohol or bad bacteria in the small intestine.

Vitamin B12 is essential in our health and it can be replenished by taking daily supplements and having a healthy diet.


I am a pop culture and social media expert. Aside from writing about the latest news health, I also enjoy pop culture and Yoga. I have BA in American Cultural Studies and currently enrolled in a Mass-Media MA program. I like to spend my spring breaks volunteering overseas.

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