COBALAMIN (Vitamin B12)

 Main Characteristics

• Vitamin B12 is a water-soluble vitamin, considered the largest and most complex of all vitamins. Its name is due to the presence of the essential trace element, cobalt, which is also responsible for the red color.

• It can be linked to several compounds and thus receive different names, such as: methylcobalamin, hydroxocobalamin, cyanocobalamin, among others.

• Vitamin B12 is synthesized only by microorganisms, is present in animal tissues and is stored in the liver in the form of adenosylcobalamin.

• Vitamin B12 participates in lipid metabolism, DNA synthesis and methylation reactions in the body.

• Vitamin B12 deficiency leads to megaloblastic anemia, neuropathy and increased homocysteine ​​levels.

• Main Functions and Mechanisms of Action

• Protection against cancer: Vitamin B12 also participates in DNA synthesis and repair, thus protecting against chromosome damage.

• Brain protection and improved cognitive function: High homocysteine ​​levels are related to brain changes.

• Control of homocysteine ​​levels and protection against cardiovascular diseases: Vitamin B12 plays an important role in homocysteine ​​metabolism, preventing its levels from rising, thus protecting the body against oxidative stress, inflammation, coagulant effect, among others.

• Protection against neural tube defects: Adequate levels of vitamin B12 may also be necessary for the perfect formation of the neural tube.

• Protection against complications related to Diabetes: Increased homocysteine ​​levels are associated with diabetic neuropathy. Vitamin B12 also appears to improve insulin resistance.

• Prevention against osteoporosis: High homocysteine ​​levels increase the risk of osteoporosis.

 • Prevention of pernicious anemia: This autoimmune disease is caused by the loss of function of gastric cells that secrete hydrochloric acid and intrinsic factor, reducing the absorption of vitamin B12 and generating megaloblastic or pernicious anemia, which is related only to the intrinsic factor.  

Bioavailability

• The absorption of vitamin B12 involves complex biochemical processes in the gastrointestinal tract itself: after the release of vitamin B12, it binds to an intrinsic factor and is absorbed in the ileum.

• The bioavailability of vitamin B12 depends on the gastrointestinal absorption system.

Possible interactions

• Drugs such as: biguanides (metformin), oral contraceptives, tetracyclines, antacids (proton pump inhibitors and H2 receptor antagonists), alcohol, colchicine, phenytoin, slow-release potassium-chloride medications, cause depletion of vitamin B12 in the body.

Interaction between Nutrients

• There are no reports of interactions with other vitamins; consumption with other B vitamins is only recommended, since they act together.

 

Scientific evidence regarding the effectiveness of supplementation

• Supplementation with B9, B6 and B12 has been shown to be effective in reducing plasma homocysteine ​​levels to levels that are not significant for the risk of arterial disease.

• A study demonstrated that vegetarians frequently ingest large amounts of carbohydrates, dietary fiber, magnesium, potassium, folate, antioxidants and phytochemicals. However, greater attention is needed with regard to the intake of calcium, zinc, iron and vitamin B12, especially because low intake of vitamin B12 can lead to hyperhomocysteinemia, increasing the risk of developing cardiovascular diseases.

• A nutritional status deficient in B9, B12 and B6 (non-genetic defects) is the most common cause of moderate hyperhomocysteinemia. Therefore, it is worth encouraging the consumption of foods that are sources of these B vitamins, since this constitutes a simple, effective and economical method in preventing hyperhomocysteinemia, contributing to the reduction of the risks of vascular diseases. It is important to highlight that another form of treatment is supplementation of B9, B12 and B6.

Risks of overdose

• There are no reports of toxicity.