Vitamin B12 Deficiency: Are You At Risk?

Posted on by Toni Law, RD. This entry was posted in Staying Healthy. Bookmark the permalink.

Vitamin B12 is a large and complex vitamin. A slight deficiency of it can lead to anemia, fatigue, mania, and depression. Are you deficient in B12? Many are. I recently learned that my mother-in-law, a healthy, active 75-year-old who eats well balanced diet, has a vitamin B12 deficiency. As a dietitian, I was surprised to learn this.


Vitamin B12 has been recognized for its importance in the world of science and nutrition. Over the past 80 years, three Nobel Prizes have been awarded for research related to this vitamin.  The first was awarded in 1934 for the discovery that liver, a food high in B12, could be used to treat a particular type of anemia (pernicious anemia). B12 was next recognized when the exact structure of this vitamin was discovered. The third Nobel came for the discovery of the intrinsic factor, which is a substance in the stomach that helps our bodies absorb B12.


There are a few things to pay attention to regarding this vitamin. First, stomach acid helps “unlock” B12 so that we can absorb it. As we age, the amount of acid we have in our stomach is reduced and as a result, our ability to absorb B12 is reduced. It is recommended all Americans over age 50 consume 25-100 mcg supplemental B12 per day. This should be in the form of a supplement, rather than from foods, because the type of B12 in supplements and some fortified foods do not require acid to absorb.


You may be well under 50 and think this doesn’t apply, but multiple diet trends may mean you’re missing out on the benefits of B12. Perhaps you’ve cut back on beef, liver, eggs or shellfish in an attempt to reduce your cholesterol. These are all foods that are high in B12. Vegetarian diets miss out on the B12 in meats and fish. Vegan diets miss out on the B12 in dairy products and eggs, and certain ethnicities that do not consume much dairy may be at risk of running low on it as well.


What can you do to lower your risk for B12 deficiency? If you are a meat-eater, you could include up to six ounces of lean red meat per day as suggested by the American Heart Association. If you are vegetarian, most of your B12 can come from milk, dairy products, and eggs. Vegans above age 50 can look to fortified foods or supplements to ensure adequate intake.


Are you ready to get started on increasing your B12 consumption yet? Try one of the foods listed below. Many of which are available daily in the Plaza Café! You may just find your energy levels go up as your stress levels decline.


How much Vitamin B12 do I need in a day?

Age in years Daily Vitamin B12 Needs micrograms (mcg)/day Do Not Exceed
Men and Women 19 and older 2.4 An upper limit for vitamin B12 has not been established.
Pregnant Women 19 and older 2.6
Breastfeeding Women 19 and older 2.8



Top 10 Foods High in Vitamin B12:

#1: Shellfish (Cooked Clams): 84 mcg per 3 oz serving size. Oysters and mussels are also high in B12.

#2: Liver (Beef): 70 mcg per 3 oz serving size

#3: Fish (Mackerel): 16 mcg per 3 oz serving size. Other fish high in B12: Smoked salmon, herring, tuna, canned sardines and trout.

#4: Crustaceans (Crab): 10 mcg in 3 oz serving size

#5: Fortified Soy Products (Silken Tofu): 2 mcg

#6: Fortified Cereals (All Bran): 18 mcg per cup

#7: Red Meat (Beef): 5 mcg per 3 oz serving size. Lamb is also high in B12

#8: Low Fat Dairy (Skim Milk): 1.2 mcg per cup

#9: Cheese (Swiss): 0.9 mcg per 1 oz serving size

#10: Eggs (Chicken): 0.3 mcg per yolk







Toni_LawToni Law, RD works with the patient population at UWMC. In her spare time, she enjoys Skwim (a new water sport like water polo), volleyball, stand-up paddle boarding and cooking.

This post was originally published in the RD Blog. You can visit the RD Blog and see its archives if you have a UW Medicine ID.