It is true that a vegan diet does not offer the same quantities of vitamin B12 found in lacto- ovo- vegetarian or non vegetarian diets. Nevertheless, it is also true that vegans are rarely deficient in vitamin B12. it is amazingly simple for a vegan to obtain sufficient quantities of this vitamin. Human beings have four main sources of vitamin B12. The first source is animal derived foods, such as meat fish, eggs, yogurt, and organ meats. The second source is vitamin B12 produced by bacteria within an individual´s own intestines. The third source is vitamin B12 enriched food- such as cereal. The fourth source is vitamin B12 supplements.
Although vitamin B12 is currently the most likely vitamin in which vegans may become deficient, historically this was not the case. That is because bacteria are really the source of all vitamin B12, not plants or animals. For centuries, these bacteria were present on the surfaces of unwashed plants and prior to the institution of modern sanitation, vitamin B12 produced by bacteria was abundant on the surface of numerous plants. Nowadays, this vitamin is washed off the surface of our vegetation.
Those who eat animal derived foods, including eggs and diary products are not deficient in vitamin B12 because the animal food sources have eaten soiled vegetation with vitamin B12 on the surface, and now these animals have absorbed it into their own bodies. In addition, the bacteria living within the intestines of these animals produce vitamin B12. These animals then store the bacteria derived vitamin B12 within their tissues, and the person eating this meat consumes the vitamin B12 indirectly.
Vitamin B12 is necessary for the health of the entire nervous system. People who are deficient in vitamin B12 may develop pernicious anemia, a fatal disorder. These individuals suffer from and develop irreversible nerve damage, sensitivity and redness of the tongue and psychological dysfunction. In children, vitamin b12 is needed for growth and to stimulate appetite. There are no known diseases caused by a vitamin b12 overdose. Thousands of times more than the recommended dietary allowance of vitamin B12 has been given to people through injections, with no harmful side effects.
Vegans are not the only individuals who must be concerned about vitamin b12 deficiencies. Some individuals consume enough of the vitamin, but their stomach has stopped producing intrinsic factor, needed for absorption of vitamin B12. This decrease in production of intrinsic factor may be genetic tendency. It can also occur as a result of laxative abuse or just old age. You don´t need to be bother about vitamin b12 overdose. Taking antacids or antibiotics can also lead to a vitamin B12 deficiency. Antacids counteract the stomach´s hydrochloric acid, which is needed for the absorption of vitamin B12, and thereby decrease the body´s ability to absorb vitamin B12. Antibiotics may destroy vitamin b12 producing bacteria within the intestinal tract. Some people are predisposed to vitamin B12 deficiencies; they might have insufficient production of enzymes or hydrochloric acid in their stomach to help them absorb vitamin 12, or poor absorption capabilities for vitamin B12 within the small intestine. Such individuals with absorption problem are symptom free and therefore have no idea that this is occurring.