Vitamin B12 is very essential for health as it plays a significant role in making DNA, red blood cells, etc. Since our body doesn’t make vitamin B12, we have to get it from either foods or supplements. As our body doesn’t store vitamin B12, we need to do it regularly.

How Much to Get?
The amount of vitamin B12 required depends on many things such as age, eating habits, medical conditions, and what medications are being taken.
However, the average recommended amounts, measured in micrograms (mcg), according to age, are:
Infants up to age 6 months: 0.4 mcg
Babies age 7-12 months: 0.5 mcg
Toddler age 1-3 years: 0.9 mcg
Kids age 4-8 years: 1.2 mcg
Children age 9-13 years: 1.8 mcg
Teens age 14-18: 2.4 mcg (2.6 mcg per day if pregnant and 2.8 mcg per day if breastfeeding)
Adults: 2.4 mcg (2.6 mcg per day if pregnant and 2.8 mcg per day if breastfeeding)
Food Sources
Animal foods are rich source of vitamin B12. Animal foods have it naturally, and also items that have been fortified with it. Check the product’s Nutrition Facts label to know if the food is fortified with B12.
Sources include:
Dairy products
Eggs
Fish
Meat
Poultry
Understanding the Results
A simple blood test can help in checking your vitamin B12 level. The results may be:
The normal range for vitamin B-12 in the blood is between 200 – 900 nanograms per milliliter (ng/mL). If you are at the lower end of this range, you may need follow-up testing, especially if you have symptoms.
Levels of vitamin B-12 < 200 ng/mL indicates vitamin B-12 deficiency, pernicious anemia, or an overactive thyroid. People with low vitamin B-12 levels often experience neurological symptoms.
An abnormally high vitamin B-12 levels > 900 ng/mL may suggest liver or kidney problems, diabetes, or certain forms of leukemia.
The doctor may also check the levels of methylmalonic acid (MMA) and other substances to evaluate for vitamin B-12 deficiency.
Causes of Vitamin B12 Deficiency
Vegetarians and Vegans are at a high risk of vitamin B12 deficiency.
The risk of deficiency increases with age as the absorption of vitamin is difficult and harder in the elderly.
People with weight loss surgery or any other surgery resulting in loss of parts of the stomach are at risk of this vitamin deficiency.
People who consume alcohol heavily are also at risk of deficiency.
You may also be more likely to develop vitamin B12 deficiency if you have:
Atrophic gastritis (tinned stomach lining)
Pernicious anemia (difficulty in absorbing vitamin B12)
Immune system disorders, such as Graves’ disease or lupus
Conditions that affect your small intestines, such as Crohn’s disease, celiac disease, bacterial growth, or a parasite
If you have been taking certain medications that interfere with the absorption of B12 (proton pump inhibitors, H2 Blockers, and certain diabetes medicines such as metformin).
Symptoms
A mild deficiency of vitamin B12 may not cause any symptoms. But if untreated, it may lead to symptoms such as:
Anemia
Weakness, tiredness, or lightheadedness
Pale skin
A smooth tongue
Vision loss
Heart palpitations and shortness of breath
Constipation, diarrhea, loss of appetite, or gas
Mental problems like memory loss, depression,or behavioral changes
Nerve problems like tingling or numbness, muscle weakness, and problems walking
Treatment
If you are diagnosed with pernicious anemia, you will require shots of this vitamin at first. You may also need to keep getting these shots, or take high doses of vitamin B12 supplement by mouth, or get it nasally after that.
If you are a vegan or vegetarian, change your diet to include vitamin B12-fortified grains or a supplement or B12 injections, or a high-dose oral vitamin B12 in case of deficiency.
Older adults with vitamin B12 deficiency should take a daily B12 supplement or a multivitamin that contains B12.
Any nerve damage due to the deficiency could be permanent.
Prevention
You can prevent vitamin B12 deficiency by eating enough meat, seafood, poultry, dairy products, and eggs.
If you don’t eat animal products, or your body doesn’t absorb the vitamin, then you can take vitamin B12 in a multivitamin supplement or B12 supplement alone, and foods fortified with vitamin B12.
Consult your doctor if you choose to take vitamin B12 supplements so that they can tell you how much you need, or make sure the supplement won’t affect any medicines you’re considering.