In this installment of Simple Food Terms Explained, we break down what exactly vitamin B12 is and everything you need to know about it, from how to get it in your diet to signs that you’re deficient.

What Is B12?

Vitamin B12 is part of the vitamin B complex, which is a group of all the water-soluble vitamins (excluding vitamin C). You’ve probably seen most of them on a nutrition label, but didn’t know what they were. These include vitamin B1 (riboflavin), vitamin B2 (riboflavin), vitamin B3 (niacin), vitamin B5 (pantothenic acid), vitamin B6 (pyridoxine), vitamin B12 (cobalamins), biotin and folic acid. Although they are all related to each other, they each have a special function within the body.

Why Do I Need B12?

There are several bodily functions that require B12, including proper formation of red blood cells, maintaining neurological function, and DNA synthesis. Outside of necessary functions, many people take B12 for other reasons, including maintaining energy levels, improving memory, boosting mood, and maintaining healthy skin and hair.

What Are Some Healthy Sources Of B12?

B vitamins can either be naturally in a food or added to it, which is why they are seen on both the nutrition facts and the ingredients list. All B12 comes from micro-organisms, made by the gut bacteria in animals. Humans don’t have the ability to make their own B12. When B12 occurs naturally, it is bound to protein and released by hydrochloric acid in the stomach to be further broken down. Some natural sources of B12 include:

  • beef
  • poultry
  • pork
  • clams
  • oysters
  • mussels
  • crab
  • sardines
  • salmon
  • tuna
  • egg

Note that fruit and vegetables are not on this list, as they are not a sufficient source of vitamin B12. Most of the natural sources listed are derived from animal products, so for vegetarians and vegans, healthy sources of B12 are listed below:

  • soy burgers
  • nutritional yeast
  • fortified plant-based milk
  • vitamin B12 supplements
  • fortified breakfast cereals

How Do I Know If I’m Deficient?

There are a wide range of symptoms associated with B12 deficiency, including (but not limiting to):

  • fatigue
  • weakness
  • anemia
  • constipation
  • numbness or tingling in the hands and feet
  • loss of appetite
  • weight loss
  • depression
  • loss of balance
  • confusion
  • poor memory
  • soreness of mouth
  • abnormal heart problems

How Much B12 Do I Need?

The amount of B12 that an individual needs varies based on their age, height, weight, athletic activity level, and other factors. Overall, the recommended values are listed below:

  • 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
  • Adults: 2.4 mcg
  • Pregnant women: 2.6 mcg
  • Breastfeeding women: 2.8 mcg