What Causes Vitamin B12 Deficiency

Before knowing what causes vitamin B12 deficiency in the body, let's get a brief idea of what role vitamin B12 plays in the human body.

Vitamin B12 is one of the forms of vitamin B. It is a complex structure that plays an important role in proper functioning of the brain and nervous system. It acts as a cofactor in conversion of methylmalonic acid into succinyl-CoA, and conversion of homocysteine into methionine along with folic acid. It is also plays a key role for repairing the damaged body cells and synthesizing essential DNA (Deoxyribonucleic acid) molecules. It helps to stimulate the mechanisms required for detoxification of the body by removing poisonous chemical substances like lead, arsenic and antimony.

Vitamin B12 Deficiency Symptoms

In adults, the symptoms become noticeable only after few months as adult humans have extensive reserves of vitamin B12 in the body which can be used later. Whereas, in infants and children, the vitamin B12 deficiency symptoms become apparent quite early.

Some of the observed symptoms are as follows:

• Rapid and shorter breathing
• Weak pulse rate and abnormal heartbeats
• Frequent headache, feeling weak, tired and lightheaded
• Sore tongue, mouth, throat and bleeding gums
• Loss of appetite and weight
• Diarrhea and constipation
• Numbness or tingling in the fingers and toes
• Depression
• Dementia, i.e. loss of mental abilities

Causes for Vitamin B12 Deficiency

Other than aging and absence of vitamin B12 rich dietary supplements like meat, animal products, fishes, eggs and dairy products in the diet, there are some possible medical causes for vitamin B12 deficiency which are as follows:

• Blind Loop Syndrome: It is a rare intestinal defect that mainly occurs due to bacterial overgrowth and malabsorption of essential nutrients. It develops as a small loop in the intestines that allow the digesting material to enter but not exit.
• Crohn's Disease: It is an inflammatory disease of intestine that affects any region of the gastrointestinal tract from the anus to the mouth, leading to abdominal pain, diarrhea, vomiting, weight loss, etc.
• Diphyllobothrium Latum: It is a human intestinal infection that occurs due to frequent consumption of raw or pickled fish. The symptoms observed are diarrhea, abdominal pain, vomiting, weight loss, fatigue, constipation, etc.
• Pernicious Anemia: It is a chronic progressive anemia which occurs due to poor intestinal absorption of vitamin B12 due to the defective production of intrinsic factor (a glycoprotein, essential for vitamin B12 absorption) by the gastric mucosa.
• Vegetarianism: It is a dietary practice of totally avoiding meat products in a regular diet and consuming only vegetables, grains and nuts. Plants are not good source of vitamin B12, hence, strictly following this diet can cause vitamin B12 deficiency in the body.
• Atrophic Gastritis: It is a chronic inflammation of the stomach mucosa that causes loss of gastric glandular cells which are ultimately replaced by intestinal and fibrous tissues. Due to this, the stomach's secretion of essential substances like hydrochloric acid, pepsin and intrinsic factor is diminished, which then causes digestive problems, vitamin B12 deficiency and megaloblastic anemia.

The vitamin B12 deficiency can also result from certain medications like metformin or inherited conditions like transcobalamin deficiency. The deficiency can be prevented by including animal products like milk, cheese and eggs in the diet. People who follow vegan diet can avoid this condition by daily consuming a vitamin pill or food products that are rich in vitamin B12.