Vitamins are required for life. A minimum daily dose of each vitamin is necessary to maintain good health. Significantly exceeding this dose, however, can cause illness. In general, the symptoms of vitamin toxicity include nausea, gastrointestinal problems like constipation and diarrhea, hair loss, rashes, and nerve damage. Show It is unusual to overdose on vitamins through megadose supplements, but people sometimes receive an unsafe dose of some vitamins by combining fortified foods with supplements.
Foods containing vitamin B 6: hazelnuts, potatoes, oatmeal, raisin, buckwheat, walnuts - Image Copyright: Elena Hramova / Shutterstock Vitamin overdose and toxicity rarely leads to death or serious illness. In 2012, the American Association of Poison Control Centers reported 59,028 exposures and only one death. As B vitamins are often given as supplements and found in fortified foods, there is some risk of taking too much B vitamin. There are eight B vitamins; thiamine, ribovlavin, niacin, pantothenic acid, pyridoxine, biotin, folic acid, and cobalamine. Each functions as an enzymatic cofactor or is a precursor to an enzymatic cofactor enabling many of the basic functions of metabolism in the body. Vitamin B1The recommended daily allowance (RDA) of vitamin B1 (thiamin) is 1.5 mg per day for an adult, and 0.7 mg for children age 1 to 4. Thiamine is generally nontoxic. Vitamin B2The RDA for vitamin B2 (riboflavin) is 1.7 mg for adults and 0.8 mg for children age 1 to 4. Vitamin B2 is also generally nontoxic. Vitamin B3The RDA for vitamin B3 (niacin) is 20 mg for adults, and 9 mg for children between 1 and 4. There is no toxic dose established in humans. However, at doses higher than 50 mg per day, some side effects such as skin flushing can occur. Therapeutic doses of 1500 to 1600 mg per day can be given, but with a risk of liver toxicity, especially in the presence of pre-existing liver disease. There were 1374 exposures to niacin toxicity reported in 2015. Vitamin B5The recommended adequate intake of vitamin B5 (pantothenic acid) is 5 mg per day for adults. It is not known to be toxic in humans and there is no tolerable upper intake level established. Diarrhea has been documented at intakes of 10 to 20 g per day. Vitamin B6The RDA for vitamin B6 (pyridoxine) is 1.3 mg for adults between 19 and 50 years. . An acute toxic dose has not been established but it is known that vitamin B6 may cause neurotoxicity at a dose of 300 to 500 mg per day over time. In 2015, 189 toxic exposures were reported for Vitamin B6. Vitamin B7Vitamin B7 (biotin) is a cofactor for key enzymes in the process of gene regulation. The recommended intake of biotin is 30 mcg per day in adults. Biotin is not considered to be toxic, and no tolerable upper intake level has been established. Vitamin B9The RDA for vitamin B9, folic acid, is 400 mcg per day for people over 14, 600 mcg for pregnant women, and 500 mcg for lactating women. Requirements for children are dependent on age. The safe upper limit of folic acid for adults is 1000 mcg from fortified foods and supplements. Taking more than that could conceal the signs of a vitamin B12 deficiency in older people. Vitamin B12The RDA for vitamin B12 (cobalamine) is 2.4 mcg for people over age 14. The RDA for children is dependent on age. No tolerable upper intake level for vitamin B12 is established. Sources
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Last Updated: Feb 27, 2019  Written by Dr. Catherine ShafferCatherine Shaffer is a freelance science and health writer from Michigan. She has written for a wide variety of trade and consumer publications on life sciences topics, particularly in the area of drug discovery and development. She holds a Ph.D. in Biological Chemistry and began her career as a laboratory researcher before transitioning to science writing. She also writes and publishes fiction, and in her free time enjoys yoga, biking, and taking care of her pets. CitationsPlease use one of the following formats to cite this article in your essay, paper or report:
How much vitamin B does it take to overdose?There is no toxic dose established in humans. However, at doses higher than 50 mg per day, some side effects such as skin flushing can occur. Therapeutic doses of 1500 to 1600 mg per day can be given, but with a risk of liver toxicity, especially in the presence of pre-existing liver disease.
What happens if we have too much vitamin B?What happens if you get too much vitamin B complex? You're unlikely to get too much vitamin B complex from your diet. That's because B complex vitamins are water soluble. That means they aren't stored in your body but are excreted in your urine daily.
Can too much B complex be harmful?Potential side effects
However, taking supplements that contain excessively high and unnecessary quantities of B vitamins could lead to serious side effects. High doses of supplemental B3 (niacin) may lead to vomiting, high blood sugar levels, skin flushing, and even liver damage ( 34 ).
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