Heart Health
Biotin supplements
Ask the doctor
Q. Your Q&A about elevated troponin levels in the October 2023 issue reminded me about a related issue I've been wondering about. I'm a 76-year-old woman with heart disease, which has necessitated several visits to the emergency room in recent years. I've heard that biotin supplements, which are supposed to promote hair and nail growth, can affect the accuracy of a troponin test. If this is a valid concern, is there a threshold for the amount of biotin a person can take? It's found in nearly all multivitamins.
A. Yes, taking supplements that contain high levels of biotin (vitamin B7) can lead to falsely low or falsely high results on a troponin test. Troponin, a protein found in heart muscle, is released into the bloodstream during a heart attack. Measuring blood troponin levels is the standard way to diagnose a heart attack.
The biotin issue is a valid concern. Inaccurate results on a troponin test can lead to a missed diagnosis with potentially serious consequences, according to a 2017 warning letter from the FDA. In at least one case, a person who was taking high doses of biotin died following a falsely low troponin test result.
The problem occurs because laboratory tests use technology that incorporates biotin because it binds to specific proteins, including troponins. Excess biotin in the blood can interfere with the biotin used in the test. However, since the FDA's warning, many — but not all — troponin test manufacturers have taken steps to address this risk.
How much biotin is too much? The recommended dietary allowance (RDA) for biotin is 0.03 milligrams (mg), which you can easily get just by eating a healthy, varied diet. The best dietary sources include eggs, fish, nuts, seeds, and vegetables, especially sweet potatoes. 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.
A biotin deficiency can cause hair loss and brittle nails. But that doesn't mean healthy people will reap any benefit from biotin supplements. According to the NIH Office of Dietary Supplements, the claims supporting better hair and nail health from biotin supplements are based on a few case reports and small studies.
Doctors sometimes suggest taking a multivitamin if there's concern that you aren't getting sufficient amounts of one of more vitamins or minerals. If you do take a multivitamin, avoid brands that contain more than the RDA for biotin.
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About the Author
Christopher P. Cannon, MD, Editor in Chief, Harvard Heart Letter; Editorial Advisory Board Member, Harvard Health Publishing
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