Vitamin B-12 is a water-soluble vitamin naturally contained in some foods, added to others and is available as a dietary supplement. Vitamin B-12 aids in neurological formation, DNA synthesis, and is needed for proper red blood cell formation, stated the National Institutes of Health. The Institute of Medicine reported that the toxicity risk of vitamin B-12 is low, and there are usually no adverse side effects from excess vitamin B-12. However, elevated levels of vitamin B-12 can lead to some health concerns. Check with your doctor first before adding vitamin B-12 supplements to your diet.
Stomach Pains
Georges Mouton, M.D., for the International Health News in February 2006 stated that pain in the abdomen could be one symptom of elevated levels of vitamin B-12. Mouton stated that the pain could sometimes feel similar to irritable bowel syndrome, or IBS. Mouton and MayoClinic.com also listed diarrhea as a symptom of elevated levels of vitamin B-12 that has been reported by some people.
Elevated Levels of B12
Normal levels of vitamin B-12 range from 200 pg/mL to 900 pg/mL, according to Mouton. High levels of vitamin B12 are considered to be anything above the 900pg/mL healthy upper limit. The Institute of Medicine did not set an upper limit for intake of B-12, but Mouton recommends staying below 900pg/mL for a healthy, well balanced diet. Some foods high in vitamin B-12 that could put you over the high range if consumed too much are milk, milk products, fish, and red meat. The National Institute of Health claimed that it is rare for people to achieve very high levels of B-12 through their diet, and that most people reach elevated levels through the use of supplementation.
Itching, Rashes, and Rosacea
MayoClinic.com claims that elevated levels of vitamin B-12 can lead to itching skin, rashes, and even rosacea fulminans, a facial skin disease that causes painful lesions. The itching and rashes produced by elevated levels of B-12 can persist up to four months after you stop taking B-12 supplements, and may require topical treatment, MayoClinic.com.
Allergic Reactions
Allergic reactions have been reported by people with elevated levels of vitamin B-12. MayoClinic.com also suggests that people who are sensitive or allergic to cobalamin or cobalt should avoid taking B-12 supplements. Sings of an allergic reaction to vitamin B-12 includes flushing and redness of the skin, itching of the skin, and a throbbing head, stated Anastasia Toufexis in an April 1992 article for "Time" magazine. Toufexis claimed that oral supplements are more likely to cause allergic reactions in sensitive individuals, and recommended vitamin B-12 injections instead.
References
- National Institutes of Health: Office of Dietary Supplements; Dietary Supplement Fact Sheet: Vitamin B12; May, 2010
- Institute of Medicine; Dietary Referentce Intakes for Thiamin, Riboflavin, Niacin, Vitamin B6, Folate, Vitamin B12, Panothenic Acid, Biotin, and Choline; June, 2000
- International Health News; Elevated Blood Levels of Vitamin B12; Georges Mouton, MD; February, 2006
- MayoClinic; Vitamin B12; April, 2011
- "Time"; The New Scoop on Vitamins; Anastasia Toufexis; April, 1992
