Nutrient Key Information | |||
Nutrient Name: | Vitamin B12 | ||
Nutrient Category: | Vitamins and Other Components | ||
Measuring Unit: | µg | ||
Nutrient Summary: | Vitamin B12 is essential for normal blood formation and body neurological function. | ||
Nutrient Function: |
Vitamin B12 is processed in the stomach and the small intestine, and then released into the circulation. To absorb vitamin B12 from foods, there are two steps (vitamin B12 absorption from supplements only needs step #2): 1) Hydrochloric acid and the digestive enzyme pepsin in the stomach separates vitamin B12 from the protein that it's attached to. 2) Then the freed vitamin B12 combines with a protein secreted by the stomach, called intrinsic factor. Now the small intestine's receptors can recognize and absorb the Vitamin B12. Some people cannot absorb Vitamin B12 well: 1) People older than 50 years old who produce less hydrochloric acid in their stomach. 2) People who eat little or no animal foods. 3) People with autoimmune diseases who cannot produce enough hydrochloric acid and/or intrinsic factor. 4) People with stomach or intestinal surgery who cannot produce enough hydrochloric acid and/or intrinsic factor. 5) People who take some medication which suppresses gastric acid production. In the body, vitamin B12 is circulated via bile and delivered back to the intestine where it is reabsorbed. |
Vitamin B12 Chemistry Structure
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Vitamin B12 Rich Foods
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Sample Foods High in: Vitamin B12 |
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Food Description | Nutrient Amount1 | Daily Value%2 | |
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Mollusks, clam, mixed species, cooked, moist heat
Category: Finfish and Shellfish Products
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98.89 µg | 4,120.42% |
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Beef, variety meats and by-products, liver, cooked, pan-fried
Category: Beef Products
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83.13 µg | 3,463.75% |
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Mollusks, oyster, Pacific, cooked, moist heat
Category: Finfish and Shellfish Products
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28.8 µg | 1,200.00% |
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Fish, mackerel, Atlantic, cooked, dry heat
Category: Finfish and Shellfish Products
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19 µg | 791.67% |
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Fish, tuna, fresh, bluefin, cooked, dry heat
Category: Finfish and Shellfish Products
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10.88 µg | 453.33% |
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Milk, reduced fat, fluid, 2% milkfat, with added vitamin A and vitamin D
Category: Dairy and Egg Products
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0.55 µg | 22.92% |
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Beef, plate steak, boneless, outside skirt, separable lean and fat, trimmed to 0" fat, all grades, cooked, grilled
Category: Beef Products
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7.72 µg | 321.67% |
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Turkey, retail parts, drumstick, meat only, cooked, roasted
Category: Poultry Products
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2.53 µg | 105.42% |
Additional Nutrient Information | |
Nutrient Summary | Vitamin B12 is essential for normal blood formation and body neurological function. |
Deficiency Health Effects |
Usually vitamin B12 deficiencies are caused by lack of hydrochloric acid (releasing vitamin B12 from foods) or lack of intrinsic factor (enabling vitamin B12 absorption) in the stomach. The common symptom of vitamin B12 deficiency is fatigue or lack of energy. The main problems vitamin B12 deficiency can cause are:
Note: Excessive folate intake from supplement may obscure the vitamin B12 deficiency that can result in unrecognized neurological damage. |
Effects if Above Upper Limit |
Due to inadequate data on adverse effects of excess vitamin B12 consumption, a Upper Limit for the vitamin B12 could not be determined. No adverse effects have been associated with excess vitamin B12 intake from food or supplements in healthy individuals. Apparently only a small percentage of vitamin B12 can be absorbed from the gastrointestinal tract. |
External References |
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Daily Value Age Group | Recommended Daily Values | |
Toddler 1 to 3 years old: | 0.9 µg | |
Child 4 to 8 years old: | 1.2 µg | |
Male 9 to 13 years old: | 1.8 µg | |
Male 14 to 18 years old: | 2.4 µg | |
Male 19 to 30 years old: | 2.4 µg | |
Male 31 to 50 years old: | 2.4 µg | |
Male 51 to 70 years old: | 2.4 µg | |
Male Senior 71 or older: | 2.4 µg | |
Female 9 to 13 years old: | 1.8 µg | |
Female 14 to 18 years old: | 2.4 µg | |
Female 19 to 30 years old: | 2.4 µg | |
Female 31 to 50 years old: | 2.4 µg | |
Female 51 to 70 years old: | 2.4 µg | |
Female Senior 71 or older: | 2.4 µg | |
Female Pregnancy (>18): | 2.6 µg | |
Female Lactation (>18): | 2.8 µg | |
FDA (Based on 2000 calorie daily diet): | 2.4 µg |
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The nutrient Dietary Reference Intakes and nutrition facts is from Institute of Medicine of National Academies 2006. Dietary Reference Intakes: The Essential Guide to Nutrient Requirements. Washington, DC: The National Academies Press. https://doi.org/10.17226/11537 |
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Nutrition facts knowledge are based on U.S. FOOD & DRUG Administration Nutrition Education Resources & Materials. https://www.accessdata.fda.gov/scripts/interactivenutritionfactslabel/ |
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Nutrition facts knowledge are based on National Institutes of Health Dietary Supplement Fact Sheets. https://ods.od.nih.gov/factsheets/list-all |
Disclaimer | The nutrient information provided here should not take the place of medical advice. We encourage you to talk to your healthcare providers (such as your doctor) about your dietary requirements which are best for your overall health. We also recommend you to read organization or professional reference documents or articles mentioned, but not limited to, in this page. Any mentions and reference links in this page don't represent our endorsement of their services and advice. |