Vitamin B12

This is a reader-friendly overview of Vitamin B12. For more details, see our health master fact sheet on Vitamin B12 .

What is vitamin B12 and what does it do?

Vitamin B12 is a nutrient that helps keep your soundbox ’ south blood and steel cells healthy and help make deoxyribonucleic acid, the genetic substantial in all of your cells. Vitamin B12 besides helps prevent megaloblastic anemia, a lineage discipline that makes people run down and weak .

How much vitamin B12 do I need?

The amount of vitamin B12 you need each day depends on your age. modal daily recommended amounts for different ages are listed below in microgram ( microgram ) :

Life Stage
Recommended Amount

Birth to 6 months
0.4 mcg

Infants 7–12 months
0.5 mcg

Children 1–3 years
0.9 mcg

Children 4–8 years
1.2 mcg

Children 9–13 years
1.8 mcg

Teens 14–18 years
2.4 mcg

2.4 mcg

Pregnant teens and women
2.6 mcg

Breastfeeding teens and women
2.8 mcg


What foods provide vitamin B12?

Vitamin B12 is found naturally in a wide assortment of animal foods, and manufacturers add it to some fortified foods. Plant foods have no vitamin B12 unless they are fortified. You can get commend amounts of vitamin B12 by eating a variety of foods including the following :

Reading: Vitamin B12

  • Fish, meat, poultry, eggs, milk, and other dairy products contain vitamin B12.
  • Clams and beef liver are some of the best source of vitamin B12.
  • Some breakfast cereals, nutritional yeasts, and other food products are fortified with vitamin B12.

To find out if a food has added vitamin B12, check the Nutrition Facts label external link disclaimer. Manufacturers are not required to list vitamin B12 on the label if a food naturally contains this vitamin .

What kinds of vitamin B12 dietary supplements are available?

Vitamin B12 is available in multivitamin/multimineral supplements, in B-complex supplements, and in supplements containing only vitamin B12. It is normally in a shape called vitamin b12. other common forms are adenosylcobalamin, methylcobalamin, and hydroxycobalamin. Vitamin B12 is besides available in a form that ’ randomness dissolved under your tongue ( called sublingual vitamin B12 ). Research has not shown that any form of supplementary vitamin B12 is better than the others .
The amount of vitamin B12 in supplements varies widely. Some provide doses of vitamin B12 that are a lot higher than recommend amounts, such as 500 microgram or 1,000 microgram, but your body absorbs only a small percentage of it. These doses are considered safe. Check the Supplement Facts label to see how much vitamin B12 a supplement contains .
A prescription shape of vitamin B12 can be given as a inject. This is normally used to treat vitamin B12 insufficiency. Vitamin B12 is besides available by prescription as a nasal consonant mousse that ’ s sprayed into the nozzle .

Am I getting enough vitamin B12?

Most people in the United States get enough vitamin B12 from the foods they eat. But some people have trouble oneself absorbing vitamin B12 from food. The body absorb vitamin B12 from food in a two-step process. First, hydrochloric acid in the stomach separates vitamin B12 from the protein that it ’ second attached to. Second, the exempt vitamin B12 then combines with a protein made by the stomach, called intrinsic factor, and the consistency absorbs them together .
Vitamin B12 in dietary supplements isn ’ triiodothyronine attached to protein and doesn ’ thyroxine require the first gradation. however, B12 in supplements does need to combine with intrinsic factor to be absorbed .
People with insidious anemia, an autoimmune disease, can ’ triiodothyronine make intrinsic factor. As a consequence, they have trouble absorbing vitamin B12 from foods and dietary supplements .
Vitamin B12 insufficiency affects between 3 % and 43 % of older adults. Your doctor can test your vitamin B12 degree to see if you have a insufficiency .
Certain groups of people may not get enough vitamin B12 or have trouble absorbing it :

  • Many older adults don’t have enough hydrochloric acid in their stomach to absorb the vitamin B12 that’s naturally present in food. People over 50 should get most of their vitamin B12 from fortified foods or dietary supplements because, in most cases, their bodies can absorb vitamin B12 from these sources.
  • People with an autoimmune disease called atrophic gastritis might not absorb enough vitamin B12 because they make too little hydrochloric acid and intrinsic factor in their stomach.
  • People with pernicious anemia do not make the intrinsic factor needed to absorb vitamin B12. As a result, they have trouble absorbing vitamin B12 from foods and dietary supplements. Doctors usually treat pernicious anemia with vitamin B12 shots, although very high doses of vitamin B12 given by mouth might also be effective.
  • People who have had some types of stomach or intestinal surgery (for example, to lose weight or to remove part or all of the stomach) might not make enough hydrochloric acid and intrinsic factor to absorb vitamin B12.
  • People with disorders of the stomach and small intestine, such as celiac disease or Crohn’s disease, might not absorb enough vitamin B12.
  • People who eat little or no animal foods, such as vegetarians and vegans, might not get enough vitamin B12 from their diets. Only animal foods have vitamin B12 naturally. When pregnant women and women who breastfeed their babies are strict vegetarians or vegans, their babies might also not get enough vitamin B12.

What happens if I don’t get enough vitamin B12?

Your body stores 1,000 to 2,000 times american samoa much vitamin B12 as you ’ d typically eat in a day, so the symptoms of vitamin B12 insufficiency can take several years to appear .
If you have a vitamin B12 insufficiency, you may feel tired or weak. These are symptoms of megaloblastic anemia, which is a hallmark of vitamin B12 insufficiency. You might besides have picket skin, heart palpitations, loss of appetite, burden loss, and sterility. Your hands and feet might become asleep or tingly, a signboard of heart problems. other symptoms of vitamin B12 insufficiency include problems with balance, depression, confusion, dementia, poor people memory, and discomfort of the sass or spit.

In infants, signs of a vitamin B12 insufficiency include failure to thrive, delays in reaching the distinctive developmental milestones, and megaloblastic anemia .
Vitamin B12 lack can damage the aflutter arrangement even in people who don ’ t have megaloblastic anemia, so it ’ s important to treat a insufficiency vitamin a soon as possible .

What are some effects of vitamin B12 on health?

Scientists are studying vitamin B12 to understand how it affects health. here are several examples of what this research has shown .
Some research shows that people with high levels of vitamin B12 have a higher gamble of cancer. But early research shows that the risk of cancer is higher in people with low levels of vitamin B12 or that vitamin B12 levels don ’ deoxythymidine monophosphate affect cancer hazard. More testify is needed to understand whether vitamin B12 levels affect cancer risk .
Heart disease and stroke
Vitamin B12 supplements ( along with other B vitamins ) reduce rake levels of homocysteine, a compound linked to an increased risk of having a heart attack or solidus But despite reducing homocysteine, research shows that these vitamins don ’ thymine reduce the hazard of developing cardiovascular disease or stroke .
Dementia and cognitive officiate
Most studies show that humble blood levels of vitamin B12 wear ’ thymine affect the risk of cognitive decline in older people, regardless of whether they have dementia or Alzheimer ’ south disease. More clinical trials are needed to better understand the effects of vitamin B12 supplementation on cognitive routine in older adults .
Energy and Endurance
Manufacturers frequently promote vitamin B12 supplements for energy, acrobatic performance, and endurance. But vitamin B12 doesn ’ triiodothyronine provide these benefits in people who get adequate B12 from their diet .

Can vitamin B12 be harmful?

Vitamin B12 has not been shown to cause any harm, evening at eminent doses .

Does vitamin B12 interact with medications or other dietary supplements?

Yes. Vitamin B12 supplements can interact or interfere with some medicines that you take. here are several examples .
Gastric acid inhibitors
People take gastric acidic inhibitors to treat certain digestion problems, such as gastroesophageal ebb disease and peptic ulcer disease. These drugs can interfere with vitamin B12 absorption from food by slowing the release of hydrochloric acerb into the digest, leading to vitamin B12 lack. Gastric acid inhibitors include omeprazole ( Prilosec® ), lansoprazole ( Prevacid® ), cimetidine ( Tagamet® ), and ranitidine ( Zantac® ) .
Metformin is used to treat prediabetes and diabetes. Metformin might reduce vitamin B12 preoccupation and lower blood levels of vitamin B12.

Tell your doctor, pharmacist, and other healthcare providers about any dietary supplements and prescription or over-the-counter medicines you take. They can tell you if the dietary supplements might interact with your medicines. They can besides explain whether the medicines you take might interfere with how your body absorbs or uses other nutrients .

Vitamin B12 and healthful eating

People should get most of their nutrients from food and beverages, according to the federal government ’ s Dietary Guidelines for Americans. Foods contain vitamins, minerals, dietary fiber, and other components that benefit health. In some cases, fortified foods and dietary supplements are useful when it is not potential to meet needs for one or more nutrients ( for example, during specific liveliness stages such as pregnancy ). For more information about building a healthy dietary model, see the Dietary Guidelines for Americans external link disclaimer and the U.S. Department of Agriculture ’ randomness MyPlate external link disclaimer .

Where can I find out more about vitamin B12?


This fact plane by the Office of Dietary Supplements ( ODS ) provides information that should not take the target of aesculapian advice. We encourage you to talk to your healthcare providers ( doctor, registered dietician, pharmacist, etc. ) about your sake in, questions about, or manipulation of dietary supplements and what may be best for your overall health. Any citation in this issue of a specific product or service, or recommendation from an organization or professional club, does not represent an endorsement by ODS of that product, service, or adept advice .

source :
Category : Healthy