Two steps are required for the body to absorb vitamin B12 from food:
- Hydrochloric acid in the stomach separates vitamin B12 from the protein to which vitamin B12 is attached in food.
- After this, vitamin B12 combines with a needed protein made by the stomach called intrinsic factor (IF) and is absorbed by the body. 
Vitamin B12 is naturally found in: animal foods including meats, fish, poultry, eggs and dairy. They are also found in food products fortified with B12, such as some varieties of bread and plant-based milk.
|Table 1: Selected Food Sources of Vitamin B12.  †|
|Food||Micrograms (mcg)per serving||Percent DV*|
|Clams, cooked, 3 ounces||84.1||3,504|
|Liver, beef, cooked, 3 ounces||70.7||2,946|
|Trout, rainbow, wild, cooked, 3 ounces||5.4||225|
|Salmon, sockeye, cooked, 3 ounces||4.8||200|
|Trout, rainbow, farmed, cooked, 3 ounces||3.5||146|
|Tuna fish, light, canned in water, 3 ounces||2.5||104|
|Nutritional yeasts, fortified with 100% of the DV for vitamin B12, 1 serving||2.4||100|
|Cheeseburger, double patty and bun, 1 sandwich||2.1||88|
|Haddock, cooked, 3 ounces||1.8||75|
|Beef, top sirloin, broiled, 3 ounces||1.4||58|
|Milk, low-fat, 1 cup||1.2||50|
|Yogurt, fruit, low-fat, 8 ounces||1.1||46|
|Cheese, Swiss, 1 ounce||0.9||38|
|Beef taco, 1 soft taco||0.9||38|
|Breakfast cereals, fortified with 25% of the DV for vitamin B12, 1 serving||0.6||25|
|Egg, whole, hard boiled, 1 large||0.6||25|
|Chicken, breast meat, roasted, 3 ounces||0.3||13|
|*DV = Daily Value. The U.S. Food and Drug Administration (FDA) developed DVs to help consumers compare the nutrient contents of foods and dietary supplements within the context of a total diet. The DV for vitamin B12 on the new Nutrition Facts and Supplement Facts labels and used for the values in Table 2 is 2.4 mcg for adults and children age 4 years and older. FDA required manufacturers to use these new labels starting in January 2020, but companies with annual sales of less than $10 million may continue to use the old labels that list a vitamin B12 DV of 6.0 mcg until January 202. FDA does not require food labels to list vitamin B12 content unless vitamin B12 has been added to the food. Foods providing 20% or more of the DV are considered to be high sources of a nutrient, but foods providing lower percentages of the DV also contribute to a healthful diet. |
|Table 2: Vitamin B12 Fortified Foods  †|
|Product||Vitamin B12 Content per µg /100g||Vitamin B12 Content per µg/Portion|
|Yeast extract||15 – 50||2.4 – 8|
|Meat substitute products||0.3||?|
|Juices||0.2 -0.5||0.4 – 1.0|
|Soya milk and yoghurts||0.1 – 0.5||0.2 – 1.0|
People at high risk for Vitamin B12 deficiency (include but not limited to) [2, 3]:
- Those on a strict vegetarian and vegan diet (ie: plant foods lack vitamin B12)
- Bowel disease conditions that interfere with nutrient absorption, such celiac or Crohn’s disease, bacterial overgrowth, or a parasitic infection
- Those with impaired absorption due to a loss of gastric intrinsic factor (IF must be bound to food-source B12 in order for absorption to occur)
- Commonly seen in elderly (their ability to absorb B12 from food is limited due to secreting less intrinsic factor and therefore absorbing less vitamin B12)
- Pernicious anemia (an autoimmune condition that develops when the immune system mistakenly attacks the cells that produce IF)
- People on the drug metformin for diabetes
- Those who’ve had surgery that removes the part of the stomach and/or bowel that absorbs B12 (most readily absorbed in the ileum)
- People with Achlorhydria (decline in stomach acid production, as acid exposure frees protein-bound vitamin)
- Age-related (commonly seen with elderly)
- people on long-term antacid therapy (such as proton-pump inhibitors, H2 blockers or other antacids) are at increased risk.
- Weakness, tiredness, fatigue,
- Breathlessness, shortness of breath or inability to exercise
- Heart palpitations and shortness of breath.
- Pale or jaundiced (yellowish) skin.
- Glossitis (red and swollen tongue, may cause tongue to look smooth) and Mouth Ulcers.
- Constipation, diarrhea, loss of appetite, or gas.
- Nerve problems like numbness or tingling, muscle weakness, and problems walking.
- affect your balance (poor balance) & mobility (changes to the way you walk and move).
- Vision loss/disturbed vision
- problems with concentration
- Mood changes (depressed mood)
- Confusion or conditions characterized by a decline in brain function, such as dementia (which is essentially reversible once treated, if is only cause)
- High temperatures (it’s important to remember that high temperatures are more commonly caused by illness, not a B12 deficiency)
- lack of appetite
- changes in bowel habits (including constipation or diarrhea) — [not common cause]
Depending on individual’s case, boosting your B12 levels may include †:
- through foods such as ones listed above
- discontinuing medications (with your doctor's approval) that can impair B12 absorption,
- moderating alcohol use,
- eliminating gluten from the diet (if you have celiac disease), receiving treatment for Crohn disease,
- If you are over age 50, the Institute of Medicine recommends that you get extra B12 from a supplement, since you may not be able to absorb enough of the vitamin through foods. A standard multivitamin should do the trick. 
- If you are a strict vegetarian or vegan, it’s important to eat breads, cereals, or other grains that have been fortified with vitamin B12, or take a daily supplement.
- adding oral (PO) supplements or having regular intramuscular (IM) injections of vitamin B12
- Dietary supplements: Oral (sublingual or pill) vitamin B12 is usually present as cyanocobalamin, a form that the body readily converts to the active forms methylcobalamin and 5-deoxyadenosylcobalamin. There are dietary supplements that can also contain methylcobalamin and other forms of vitamin B12.
- Prescription medication: Parenteral (injection, usually IM) Vitamin B12 is in the form of cyanocobalamin and occasionally hydroxocobalamin.
Dr. Kenawy’s Methyl B12 lozenges is provided in the form of Methylcobalamin which is the coenzyme form of Vitamin B-12 and is the form that exists in the body. Most other forms require some amount of conversion once they are consumed; methylcobalamin needs no conversion. It is the most active and effective form. This helps avoid any problems with absorption as it is dissolved in the mouth, and therefore absorbed directly into the bloodstream. This helps provide significant amounts of B12 without concern for GI absorption. The synergistic nutrients folate, vitamin B6 and biotin are provided for added support. †
- High potency formula contains 3,000 mcg of methylcobalamin.
- The formula also contains 400 mcg of folic acid, 300 mcg of biotin and 10 mg of B-6.
- Convenient dosage; lozenge dissolves under the tongue.
- Great tasting cherry flavor.
- Methylcobalamin is more bioactive than cyanocobalamin, which has to be converted by the liver to the active coenzyme form methylcobalamin before it can function in the body.
- Methylcobalamin aids in the conversion of homocysteine to methionine, supporting healthy blood homocysteine levels.
- Vitamin B-6 and folic acid work synergistically with methyl B-12 to promote healthy blood homocysteine levels.
- Methylcobalamin helps donate a methyl group to form SAMe (s- adenosylmethionine) which helps support healthy brain function and liver detoxification.
- Methylcobalamin is essential for the production of normal, healthymyelin; protects the nervous system and supports its function.
- Biotin along with B12 helps support fatty acid, amino acid and carbohydrate metabolism.
- Vitamin B-12 and folic acid support healthy red blood cell production, essential for oxygen transport throughout the body.
- Vitamin B-12 deficiency generally increases with age because of decreased levels of intrinsic factor a protein normally produced by the stomach and which aids in B12 absorption.
- Ideal source for vegan/vegetarians who are at greater risk for vitamin B-12 deficiency.
†These statements have not been evaluated by The Food and Drug Administration. This product is not intended to diagnose, treat, cure or prevent any disease. Information and statements made are for education purposes and are not intended to replace the advice of your General Practitioner. If you have a severe medical condition or health concern, see your physician.
 Vitamin B12 Fact Sheet for Consumers. (2020, March 30). National Institutes of Health. https://ods.od.nih.gov/factsheets/VitaminB12-Consumer/
 West, R. H. D. (2017). 9 Signs and Symptoms of Vitamin B12 Deficiency. Healthline. https://www.healthline.com/nutrition/vitamin-b12-deficiency-symptoms#section10
 Harvard Health Publishing. (n.d.). Ask Dr. Rob about vitamin B12 deficiency. Harvard Health. https://www.health.harvard.edu/staying-healthy/ask-dr-rob-about-vitamin-b12-deficiency
 Skerrett, P. J. (2019, February 11). Vitamin B12 deficiency can be sneaky, harmful. Harvard Health Blog. https://www.health.harvard.edu/blog/vitamin-b12-deficiency-can-be-sneaky-harmful-201301105780
 Vitamin B12 Fact Sheet for Health Professionals. (2020, March 30). National Institutes of Health. https://ods.od.nih.gov/factsheets/vitamin%20B12-HealthProfessional/
 Vitamin B12 for Vegetarians and Vegans | Dr. Schweikart. (n.d.). The Dr Schweikart Publisher and the Association for the Promotion of Holistic Health. https://www.b12-vitamin.com/vegan-vegetarian/