Vitamin B 12 is also called cobalamin. Vitamin B 12 in nature is synthesized by microorganisms. Higher animals and plants cannot produce vitamin B 12. Vitamin B 12 is the only vitamin that needs the help of intestinal secretions (endogenous factors) to be absorbed. Some people lack this endogenous factor due to gastrointestinal abnormalities, and even if the source is sufficient in the diet, they will suffer from pernicious anemia. There is basically no vitamin B 12 in plant foods. It stays in the intestine for a long time and takes about three hours (most water-soluble vitamins only take a few seconds) to be absorbed.
The main physiological functions of 1 and vitamin B 12.
(1), promote the development and maturity of red blood cells, make the hematopoietic function of the body in a normal state, and prevent pernicious anemia;
(2) Being in the form of coenzyme can improve the utilization rate of folic acid and promote the metabolism of carbohydrate, fat and protein;
(3) It can activate amino acids and promote the biosynthesis of nucleic acids, which can promote the synthesis of protein and play an important role in the growth and development of infants.
(4) It is an indispensable vitamin for the sound function of the nervous system and participates in the formation of lipoproteins in nervous tissues.
2. Vitamin B 12 deficiency and health.
(1), lack of vitamin B 12 may cause people's mental depression.
(2) Causing megaloblastic anemia (pernicious anemia)
(3) degeneration of spinal cord, nerves and peripheral nerves
(4) Mucosal inflammation of tongue, mouth and digestive tract.
(5) Children's vitamin B 12 deficiency is characterized by abnormal mental mood, dull expression, less crying and trouble, slow response, love to sleep and other symptoms, which will eventually lead to anemia.
3. Excessive and harmful vitamin B 12.
Vitamin B 12 is the last thing the human body needs every day. Excessive vitamin B 12 will produce toxic and side effects. It is reported that excessive injection of vitamin B 12 may cause allergic reactions such as asthma, urticaria, eczema, facial edema and chills, and may also cause nervous excitement, precordial pain and palpitations. Excessive intake of vitamin B 12 can also lead to folic acid deficiency.
4. The recommended daily amount of vitamin B 12
Daily recommended amount
Age group (years) Vitamin B 12 (μ g)
Baby 0- 1 0.52- 1.5
Children 1- 10 2.0-3.0
Teenagers 1 1- 18 3.0
Adult 3.0
Pregnant women 4.0
Nanny 4.0
5. The main food source of vitamin B 12.
Beef liver, beef kidney, pig liver, pig kidney, pig heart, beef, herring, shrimp, eggs, lobster, flounder, crab, stinky tofu, lobster sauce, yellow sauce and soy sauce.