Vitamin B12 is a label for a group of compounds known as cobalamins. The most common form of vitamin B12 is called cyanocobalamin.
Cobalamin functions as a source of a methyl group (a carbon molecule) for a very important biochemical cycle known as the methylation cycle. In order to do this, cobalamins must be converted to the methyl donating form called methylcobalamin. Methylcobalamin is the “active” form of cobalamins.
Signs, symptoms and health problems associated with vitamin B-12 deficiency
Deficiency characteristics include anemia, fatigue, weakness, constipation, loss of appetite, and weight loss. Deficiency also can lead to neurological changes such as numbness and tingling in the hands and feet. Additional symptoms of vitamin B-12 deficiency are difficulty in maintaining balance, depression, confusion, dementia, poor memory, and soreness of the mouth or tongue.
Signs of vitamin B-12 deficiency in infancy include failure to thrive, movement disorders, delayed development, and megaloblastic anemia. (1)
Adults over 50
Up to 30 percent of adults aged 50 years and older may have atrophic gastritis, an increased growth of intestinal bacteria, and be unable to normally absorb vitamin B-12 in food. They are, however, able to absorb the synthetic vitamin B-12 added to fortified foods and dietary supplements. Vitamin supplements and fortified foods may be the best sources of vitamin B-12 for adults older than age 50 years. (1)
One study suggests that the prevalence of vitamin B-12 deficiency in young adults may be greater than previously thought. This study found that the percentage of subjects in three age groups (26-49 years, 50-64 years, and 65 years and older) with deficient blood levels of vitamin B-12 was similar across all age groups but that symptoms of vitamin B-12 deficiency were not as apparent in younger adults. This study also suggested that those who did not take a supplement containing vitamin B-12 were twice as likely to be vitamin B-12 deficient as supplement users, regardless of age group. (1)
Methyl B-12 can be very effective in improving mental function. In a 1995 double-blind study of elderly people with low levels of B12, over 60% improved significantly with vitamin B-12 supplementation. It was suggested that those who did not improve had long-term (longer than 6 months) signs of mental impairment. (2)
Children with autism have been shown to be deficient in cysteine and glutathione and it appears that methylcobalamin can help restore the formation of the nutrients. (3)
Can I overdose on vitamin B-12?
The Institute of Medicine (an independent body that advises the government on science issues) did not establish a UL (upper intake level) for vitamin B-12 because it has a very low potential for toxicity. The IOM states that "no adverse effects have been associated with excess vitamin B-12 intake from food and supplements in healthy individuals". In fact, the IOM recommends that adults older than 50 years get most of their vitamin B-12 from vitamin supplements or fortified food because of the high incidence of impaired absorption in this age group of vitamin B12 from foods that come from animals.
Vitamin B12 is a water soluble vitamin. This means that it doesn’t stay in the body for a long period of time and that more frequent support with B12 may be needed to maintain healthy B12 levels in the body.
- Vitamin B12 is important for energy, for balance related sports, for endurance sports, for healthy red blood cells, for memory, among other roles in the body.
- Vitamin B12 can be depleted by drinking alcoholic beverages, a poor diet, certain medications and as we age.
- Lack of B12 has been associated with fatigue, alcoholic liver disease, anemia, cancer, ulcers, dementia, neural tube defects, depression and memory loss.
- Higher levels of B12 correlate with improved balance, energy, and endurance in athletics.
- Adenosyl B12 is a special form of B12 that is important in the energy cycle in the cells of your body. It is important to have adenosyl B12 but it is not as versatile as other forms of B12 so it can be used in lower doses.
- CyanoB12 contains a cyanide molecule. So when you take cyanoB12 your body must first turn it into hydroxyB12 in order to use it, and then must find a way to get rid of the toxic cyanide molecule. We all know cyanide is a poison even if the rest of the B12 molecule is good for you. The body actually uses up hydroxyB12 in order to detoxify cyanide. So, not only is cyanoB12 not the form your body ultimately needs, but taking higher doses of cyanoB12 may actually deplete your stores of hydroxy B12. So why would anyone use cyano B12 if it can be toxic? Well, in low doses it may be helpful for the eyes, but for the most part cyanoB12 is used because it is much less expensive, and a form of B12 that is easier to keep stable.