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Nutritional Supplement

Vitamin B12

Where to Find It

Vitamin B12 is found in all foods of animal origin, including dairy, eggs, meat, poultry, and fish. According to one report, small, inconsistent amounts occur in seaweed (including nori and chlorella) and tempeh.155 Many researchers and healthcare professionals believe that people cannot rely on vegetarian sources to provide predictably sufficient quantities of vitamin B12. However, another study found substantial amounts of vitamin B12 in nori (at least 55 mcg per 100 grams of dry weight).156

Best Form to Take

Cyanocobalamin, a synthetic form of vitamin B12 commonly found in supplements, is normally present only in trace amounts in the body. It has no known biological activity on its own, and must be converted by the body into active forms of vitamin B12. Supplementing with hydroxocobalamin, another form of vitamin B12, results in more sustained levels of vitamin B12 in the body compared with cyanocobalamin and can be used for conditions such as cyanide poisoning (cyanocobalamin should not be used for cyanide poisoning). Partly for these reasons, hydroxocobalamin is to be preferred as a vitamin B12 supplement over cyanocobalamin. Other acceptable forms of vitamin B12 include methylcobalamin and adenosylcobalamin, although there is no clear evidence that these forms (except in very rare cases) are preferable to hydroxocobalamin.157

How to Use It

Most people do not require vitamin B12 supplements. However, vegans should supplement with at least 2 to 3 mcg per day.

People with pernicious anemia are often treated with injections of vitamin B12. However, oral administration of 1,000 mcg per day can be used reliably as an alternative to vitamin B12 injections.158,159,160,161,162

Absorption of vitamin B12 is reduced with increasing age. Some research suggests that elderly people may benefit from 10 to 25 mcg per day of vitamin B12.163,164,165 One study of elderly people with vitamin B12 deficiency suggested that as much as 500 to 1,000 mcg of vitamin B12 per day might be necessary to achieve optimal vitamin B12 status.166 Vitamin B12 status was measured in this study using a sensitive laboratory test (the plasma methylmalonic acid concentration).

When vitamin B12 is used for therapeutic purposes other than correcting a deficiency, injections are usually necessary to achieve results.

Sublingual forms of vitamin B12 are available,167 but there is no proof that they offer any advantage to oral supplements.

References

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The information presented by TraceGains is for informational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, or traditional usage as cited in each article. The results reported may not necessarily occur in all individuals. For many of the conditions discussed, treatment with prescription or over the counter medication is also available. Consult your doctor, practitioner, and/or pharmacist for any health problem and before using any supplements or before making any changes in prescribed medications. Information expires December 2020.

Copyright © 2020 TraceGains, Inc. All rights reserved.

The information presented by TraceGains is for informational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, or traditional usage as cited in each article. The results reported may not necessarily occur in all individuals. Self-treatment is not recommended for life-threatening conditions that require medical treatment under a doctor's care. For many of the conditions discussed, treatment with prescription or over the counter medication is also available. Consult your doctor, practitioner, and/or pharmacist for any health problem and before using any supplements or before making any changes in prescribed medications. Information expires December 2020.