- Diet, inability to break the B12-Protein bond, or inadequate IF (intrinsic factor) may result in a B12 deficiency. The deficiency can result in anemia, non-reversible neural damage, and other problems.
- B12 is water soluble, the excess is eliminated, and there is not an upper limit.
- Microwaves inactive B12. However, stovetop and oven heat do not inactivate it.
- HHS recommends older adults obtain B12 from fortified cereals or vitamin supplements.
- There is only enough IF for the absorption of about 2 mcg of B12. However, the current thought is that if sufficient B12 is consumed, 1% to 56% of it can be absorbed without IF. About 56% of 2 mcg or 20% 50 mcg in a vitamin B12 supplement is absorbed.
- The B12 level can be determined from blood tests.
- B12 is created by microbes and it is obtained only from animal products, fortified cereals, vitamin supplements, and injections. Milk and fish have the greatest bioavailable of B12. Swiss cheese has more than other cheeses.
|B12 per oz||Amt to obtain 2.4 mcg|
|Swiss||.95 mcg||2.5 oz|
|Cheddar||0.24 mcg||10 oz|
|0–6 months*||0.4 mcg||0.4 mcg|
|7–12 months*||0.5 mcg||0.5 mcg|
|1–3 years||0.9 mcg||0.9 mcg|
|4–8 years||1.2 mcg||1.2 mcg|
|9–13 years||1.8 mcg||1.8 mcg|
|14+ years||2.4 mcg||2.4 mcg||2.6 mcg||2.8 mcg|
NIH list of some of the B12 sources
|Clams, cooked, 3 ounces||84.1||1,402|
|Liver, beef, cooked, 3 ounces||70.7||1,178|
|Breakfast cereals, fortified with 100% of the DV for vitamin B12, 1 serving||6.0||100|
|Trout, rainbow, wild, cooked, 3 ounces||5.4||90|
|Salmon, sockeye, cooked, 3 ounces||4.8||80|
|Trout, rainbow, farmed, cooked, 3 ounces||3.5||58|
|Tuna fish, light, canned in water, 3 ounces||2.5||42|
|Cheeseburger, double patty and bun, 1 sandwich||2.1||35|
|Haddock, cooked, 3 ounces||1.8||30|
|Breakfast cereals, fortified with 25% of the DV for vitamin B12, 1 serving||1.5||25|
|Beef, top sirloin, broiled, 3 ounces||1.4||23|
|Milk, low-fat, 1 cup||1.2||18|
|Yogurt, fruit, low-fat, 8 ounces||1.1||18|
|Cheese, Swiss, 1 ounce||0.9||15|
|Beef taco, 1 soft taco||0.9||15|
|Ham, cured, roasted, 3 ounces||0.6||10|
|Egg, whole, hard boiled, 1 large||0.6||10|
|Chicken, breast meat, roasted, 3 ounces||0.3||5|
National Institutes of Health, Vitamin B12 Health Professional, US Dept of Health and Human Services (HHS), February 2016
National Institutes of Health, Vitamin B12 Consumer, US Dept of Health and Human Services (HHS), June 2011
Whitney, Ellie and Sharon Rady Rolfes. Understanding Nutrition, Cengage Learning, 2016