Vitamin B12 is a B-complex vitamin that is primarily found in meat and dairy food products. Vitamin B12 is used in many different places in the body, mainly during cell division, by the nervous system and for energy production. Vitamin B12 from food sources sometimes poses difficulties for vegetarians and, in particular, vegans. Milk is an excellent source of Vitamin B12 but is something a strict vegan diet does not permit. There are also certain foods, mainly cereals, that are enriched with Vitamin B12, but the source of the Vitamin B12 used to enrich the cereal is from animal sources.
Failure to obtain Vitamin B12 from food sources can result in a deficiency. Luckily, Vitamin B12 is rather unusual because it is a water-soluble vitamin but is still stored by the body in the liver. Most water-soluble vitamins are not stored by the body. If this storage is depleted and a deficiency occurs, the most usual symptoms involve the digestive tract including nausea, vomiting and diarrhea. A Vitamin B12 deficiency can also cause nervous system problems, mainly because of insufficient myelin surrounding nerve cells. The initial symptoms of nerve damage include tingling and numbness in the hands and feet. This can cause permanent and irreversible nerve damage if the vitamin B12 deficiency is prolonged.
The major food sources of Vitamin B12 is meat, fish and dairy products. Liver has extremely high levels of Vitamin B12 (along with several other important nutrients). Almost all types of seafood contain high amounts of Vitamin B12 and because of its other health benefits, fish is always a great substitute for red meat. Milk and eggs also both contain high amounts of Vitamin B12.
Since the rise in the popularity of vegan diets, Vitamin B12 has received a lot of attention because it is one of the most difficult nutrients for a pure vegan to ingest. Because of this fact, there was a lot of quick research that was done, which in the end has turned out to be flawed. For many years, it was believed that certain plant sources like soy or seaweed could be a food source of Vitamin B12 for vegans. This turned out to be false though because the test that was done on these foods was giving a ‘false positive’ result. These foods contain a chemical called Spirulina which gives a positive result in the test used to measure Vitamin B12, unfortunately the body cannot use the chemical the same way it uses Vitamin B12 and all the symptoms of a Vitamin B12 deficiency occur even if the soy or seaweed products are eaten.
There was also a lot of research done because it was found that bacteria that live normally in the human digestive tract produce extremely large amounts of Vitamin B12. The problem is that these bacteria live in the lower part of the small intestines, so while the bacteria do produce large amounts of Vitamin B12, the Vitamin B12 they produce is already past the point in the digestive tract where it can be absorbed by the body. As a result, human feces has a very high concentration of Vitamin B12. Ironically, this was also discovered in research aimed at finding out why very poor areas of southwest asia were not stricken with vitamin B12 deficiency when meat and dairy products were seldom consumed. The reason, it was found, was because of sanitary conditions. Fecal contamination was so high in rice fields that once consumed, it was supplying adequate amounts of vitamin B12 to the individual.
Aside from Vegans, there normally is no issue with anyone receiving the proper amounts of Vitamin B12 from food sources. Even modest amounts of milk or dairy products supply enough Vitamin B12 for proper functioning. Individuals who consume meat and fish rarely will have any issues with Vitamin B12, especially since it can be stored on a limited bases in the liver. The majority of Vitamin B12 deficiency cases are a result of uneducated diets by vegans or by a disease state which prevents absorption of Vitamin B12 in consumed food.
Vitamin B12 is easily obtained in normal diets in food sources such as meat, fish and other seafood, diary products and eggs. People on restricted diets such as a vegetarian diet should make sure to increase their dairy product consumption to accommodate this important nutrient. Although early research indicated that soy and seaweed products could be used to provide Vitamin B12, this was later shown to be false. There is currently no known source of Vitamin B12 that is not derived from animal sources.