Vitamin B12 does a lot of things for your body. It helps make your DNA and your red blood cells, for example.
Since your body doesn’t make vitamin B12, you have to get it from animal-based foods or from supplements. And you should do that on a regular basis, because your body doesn’t store vitamin B12 for a long time.
How Much to Get?
The answer depends on things including your age, your eating habits and medical conditions, and what medications you take.
The average recommended amounts, measured in micrograms (mcg), vary by age:
- Infants up to age 6 months: 0.4 mcg
- Babies age 7-12 months: 0.5 mcg
- Children 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 of Vitamin B12
You can get vitamin B12 in animal foods, which have it naturally, or from items that have been fortified with it.
Animal sources include dairy products, eggs, fish, meat, and poultry. If you’re looking for a food fortified with B12, check the product’s Nutrition Facts label.
Vitamin B12 Deficiency
Most people in the U.S. get enough of this nutrient. If you’re not sure, you can ask your doctor if you should get a blood test to check your vitamin B12 level.
With age, it can become harder to absorb this vitamin. It can also happen if you have had weight loss surgery or another operation that removed part of your stomach, if you drink heavily, or if you’ve taken acid-reducing medications for a long time.
You may also be more likely to develop vitamin B12 deficiency if you have:
- Atrophic gastritis, in which your stomach lining has thinned
- Pernicious anemia, which makes it hard for your body to absorb vitamin B12
- Conditions that affect your small intestine, such as Crohn’s disease, celiac disease, bacterial growth, or a parasite
- Immune system disorders, such as Graves’ disease or lupus
- You can also get vitamin B12 deficiency if you follow a vegan diet (meaning you don’t eat any animal products, including meat, milk, cheese, and eggs) or you are a vegetarian who doesn’t eat enough eggs or dairy products to meet your vitamin B12 needs. In both of those cases, you can add fortified foods to your diet or take supplements to meet this need.
Pregnant or New Mom?
Are you a pregnant woman on a vegan or vegetarian diet, and plan to only breastfeed your baby? You should talk to your doctor before you have your baby, so that you have a plan in place for how you’ll get enough vitamin B12 to keep your baby healthy.
Without enough vitamin B12, your baby could have developmental delays and not thrive and grow like he should.
Symptoms of Vitamin B12 Deficiency
If you have vitamin B12 deficiency, you could become anemic. A mild deficiency may cause no symptoms. But if untreated, it may lead to symptoms such as:
- Weakness, tiredness, or lightheadedness
- Heart palpitations and shortness of breath
- Pale skin
- A smooth tongue
- Constipation, diarrhea, loss of appetite, or gas
- Nerve problems like numbness or tingling, muscle weakness, and problems walking
- Vision loss
- Mental problems like depression, memory loss, or behavioral changes
If you have pernicious anemia or have trouble absorbing vitamin B12, you’ll need shots of this vitamin at first. You may need to keep getting these shots, take high doses of a supplement, or get it nasally after that.
If you don’t eat animal products, you have options. You can change your diet to include vitamin B12-fortified grains, a supplement or B12 injections, or a high-dose oral vitamin B12 if you are deficient.
Older adults who have a vitamin B12 deficiency should take a daily B12 supplement or a multivitamin that contains B12.
For most people, treatment resolves the problem. But, any nerve damagethat happened due to the deficiency could be permanent.
Most people can prevent vitamin B12 deficiency by eating enough meat, poultry, seafood, dairy products, and eggs.
If you don’t eat animal products, or you have a medical condition that limits how well your body absorbs nutrients, you can take vitamin B12 in a multivitamin or other supplement and foods fortified with vitamin B12.
If you choose to take vitamin B12 supplements, let your doctor know, so he or she can make sure they won’t affect any medicines you’re taking.
What does vitamin B12 do?
The human body needs vitamin B12 to make red blood cells, nerves, DNA, and carry out other functions. The average adult should get 2.4 micrograms a day. Like most vitamins, B12can’t be made by the body. Instead, it must be gotten from food or supplements.
And therein lies the problem: Some people don’t consume enough vitamin B12 to meet their needs, while others can’t absorb enough, no matter how much they take in. As a result, vitamin B12 deficiency is relatively common, especially among older people. The National Health and Nutrition Examination Survey estimated that 3.2% of adults over age 50 have a seriously low B12 level, and up to 20% may have a borderline deficiency.
Are you at risk?
There are many causes for vitamin B12 deficiency. Surprisingly, two of them are practices often undertaken to improve health: a vegetarian diet and weight-loss surgery.
Plants don’t make vitamin B12. The only foods that deliver it are meat, eggs, poultry, dairy products, and other foods from animals. Strict vegetarians and vegans are at high risk for developing a B12 deficiency if they don’t eat grains that have been fortified with the vitamin or take a vitamin supplement. People who have stomach stapling or other form of weight-loss surgery are also more likely to be low in vitamin B12 because the operation interferes with the body’s ability to extract vitamin B12 from food.
Conditions that interfere with food absorption, such celiac or Crohn’s disease, can cause B12trouble. So can the use of commonly prescribed heartburn drugs, which reduce acid production in the stomach (acid is needed to absorb vitamin B12). The condition is more likely to occur in older people due to the cutback in stomach acid production that often occurs with aging.
Recognizing a B12 deficiency
Vitamin B12 deficiency can be slow to develop, causing symptoms to appear gradually and intensify over time. It can also come on relatively quickly. Given the array of symptoms it can cause, the condition can be overlooked or confused with something else. Vitamin B12deficiency symptoms may include:
- Strange sensations, numbness, or tingling in the hands, legs, or feet
- Difficulty walking (staggering, balance problems)
- A swollen, inflamed tongue
- Yellowed skin (jaundice)
- Difficulty thinking and reasoning (cognitive difficulties), or memory loss
- Paranoia or hallucinations
While an experienced physician may notice the symptoms and be able to detect a vitamin B12 deficiency with a good interview and physical exam, a blood test is needed to confirm the condition.
Early detection and treatment is important. “If left untreated, the deficiency can cause severe neurologic problems and blood diseases,” says Dr. Bruce Bistrian, chief of clinical nutrition at Harvard-affiliated Beth Israel Deaconess Medical Center.
It’s a good idea to ask your doctor about having your B12 level checked if you:
- are over 50 years old
- take a proton-pump inhibitor (such as Nexium or Prevacid) or H2 blocker (such as Pepcid or Zantac)
- take metformin (a diabetes drug)
- are a strict vegetarian
- have had weight-loss surgery or have a condition that interferes with the absorption of food
A serious vitamin B12 deficiency can be corrected two ways: weekly shots of vitamin B12 or daily high-dose B12 pills. A mild B12 deficiency can be corrected with a standard multivitamin.
In many people, a vitamin B12 deficiency can be prevented. 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. A standard multivitamin delivers 6 micrograms, more than enough to cover the average body’s daily need.
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.