What is vitamin B12?
Vitamin B 12 , also known as cobalamin, is a water-soluble vitamin.
What are the functions of vitamin B12?
Our body needs vitamin B12 for the production of the red blood cells, efficient functioning of the nervous system and produce deoxyribonucleic acid (DNA).
What are the sources of vitamin B12?
Micro-organisms (bacteria) in the digestive tract of animals produce vitamin B12. It is subsequently absorbed into the animal tissues. Thus, only foods of animal origin such as eggs, fish, meat, poultry, milk and milk products contain vitamin B12.
Plant foods such as tempeh, miso, shiitake mushrooms, spirulina, among many others contain analogues of vitamin B12. They can also be termed as or pseudo vitamin B12. They are chemically similar in structure to vitamin B12, but are present in the inactive form. They end up interfering with the metabolism of actual vitamin B12 by inhibiting absorption. Thus, consumption of plant foods does not meet any vitamin B12 requirement.
How is vitamin B12 absorbed?
The ingested B12 binds with intrinsic factor (IF), which is produced and secreted by the cells (gastric parietal) in the stomach, for active absorption of the vitamin. The amount of B12 that can be absorbed by the body (also known as bioavailability) depends upon the quantity of B12 rich foods consumed and varies from person to person based on their digestive absorption capacity.
What are the causes of vitamin B12 deficiency?
Vitamin B12 deficiency can stem from:
1. Inadequate intake of vitamin B12 in the diet.
2. Destruction of stomach cells (gastric parietal) that produce IF (which is required for active absorption of vitamin B12) leading to inefficient absorption of B12 in the digestive tract.
3. Usage of certain prescription drugs that interfere with the absorption of vitamin B12, such as proton pump inhibitors and H2 blockers (reduces the amount of acid produced in the stomach) and metformin (reduces the amount of sugar in the blood, often prescribed to type 2 diabetics and those with PCOS).
Who is vulnerable to vitamin B12 deficiency?
1. Those in whom the stomach cells (gastric parietal) are destroyed leading to inability to produce IF (happens in a condition known as pernicious anemia)
2. Those with advancing age who suffer from inability to produce acid (hydrochloric acid) in the stomach (known as age related hypochlorhydria)
3. Those who have swelling in the stomach lining (known as atrophic gastritis)
4. Those who are sensitive to gluten (protein found in wheat, rye and barley) which ends up affecting their small intestine (known as celiac disease)
5. Those who have swelling in the digestive system (known as Crohn’s disease)
6. Those who shun all animal and animal related products in their diet and lifestyle, also known as vegans. Since plants do not contain vitamin B12, vegans are at risk of being B12 deficient. Nevertheless, it should not worry vegans as there is a way out. Please read below to understand how you can ensure to have good vitamin B12 levels despite being vegan.
How do I assess my vitamin B12 status?
Usually a blood test to check serum vitamin B12 level is recommended. But two other tests; namely, methylmalonic acid and homocysteine can better indicate your vitamin B12 status. You should not neglect vitamin B12 deficiency as it can lead to improper production of red blood cells that leads to a certain type of anemia (known as megaloblastic anemia) and problems of the nervous system.
So, what should vegans do to prevent vitamin B12 deficiency?
1. Ideally, vegans should ensure to take vitamin B12 dietary supplements (also known as cyanocobalamin), that are to be taken either on a daily or a weekly basis depending upon the dosage, as prescribed by your physician.
2. In addition to dietary supplements, please supplement the diet with foods that contain added vitamin B12, which are known as fortified foods. Please read the nutrition facts panel carefully to check if the product you are buying contains vitamin B12 or not and if yes, please check the amount per serving. A few examples of foods fortified with vitamin B12 include fortified breakfast cereals, fortified plant milk, fortified spreads and fortified nutritional yeast.
Please note that the synthetic form of vitamin B12 that you get from supplements and fortified foods is free in nature and is readily absorbed, becoming an easy means for vegans to keep vitamin B12 deficiency at bay.
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