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Taking supplements that contain high levels of biotin (vitamin B7) can lead to falsely low results on a blood test used to detect heart attacks, according to an FDA warning issued late last year.
For adults, the recommended dietary allowance (RDA) for biotin is 0.03 milligrams (mg), which is easily obtained through a healthy, varied diet. Many multivitamins and prenatal vitamins contain far more biotin than the RDA. And some supplements — particularly those marketed to improve hair, nails, and skin — contain 20 mg, or nearly 650 times the RDA.
But biotin levels higher than the RDA may interfere with lab test results, including blood tests for troponin, which doctors use to diagnose heart attacks. These inaccurate results can lead to missed diagnoses with potentially serious consequences. In at least one case, a person who was taking high doses of biotin died following a falsely low troponin test result.
If you take biotin supplements, stop. Multivitamins have no proven health benefits, so there's no good reason to take them. But if you do, avoid brands that contain more than the RDA for biotin.
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