Vitamin B12 helps the body convert energy, maintain nerve cells, make DNA and produce red blood cells, according to the University of Maryland Medical Center. The normal dose for adults 19 and older is 2.4 micrograms per day.Continue Reading
Vitamin B12 helps disorders and diseases associated with a deficiency in the nutrient, notes WebMD. Pernicious anemia, a serious blood condition, occurs mostly in older people. Injections of vitamin B12 assist patients with Imerslund-Grasbeck disease, an inherited condition that causes poor absorption of vitamin B12. This nutrient may be effective for cyanide poisoning and high levels of homocysteine in the blood. Some of these disorders require patients to take folic acid and vitamin B6 along with vitamin B12, because these substances work with each other within the body.
When treating pernicious anemia, patients may receive injections of 1,000 micrograms of vitamin B12 so the bloodstream can absorb more of the substance, says the Linus Pauling Institute. Oral doses of 1,000 micrograms result in 10 micrograms in the bloodstream because the intestines do not absorb a lot of vitamin B12. Foods that originate from animal sources represent the primary method by which humans ingest vitamin B12.
The normal dose for children ages 9 to 13 is 1.8 micrograms per day, states the University of Maryland Medical Center. Breastfeeding mothers should intake 2.8 micrograms per day, and pregnant women should get at least 2.6 micrograms daily. People older than 50 may need to supplement their diets or eat foods fortified with vitamin B12, due to possible malabsorption because of old age.Learn more about Vitamins & Supplements