Knowing Your Supplements and Multivitamins Could Save Your Life

By Dace L. Trence, MD, FACE

This past fall, the U.S. Food and Drug Administration (FDA) came out with a warning that high doses of vitamin B7 (also known as biotin) found in dietary supplements can significantly interfere with many commonly ordered lab tests and cause incorrect test results which may go undetected – including tests that emergency room doctors rely on to diagnose a heart attack.

The problem has been reported to have led to at least one death, according to the FDA.

A recent EmPower Magazine article featured information about the interference of biotin on thyroid function testing ( Still, the interference problem not only continues largely unrecognized, but has become increasingly concerning since it is now evident that biotin can interfere with lab tests beyond those for thyroid function.

Biotin is a water-soluble substance found naturally in liver, eggs, fish (salmon), meat, nuts (peanuts, almonds), seeds and some vegetables. Other high-biotin foods include wheat bran, low-fat cheese and avocados. These foods can provide sufficient biotin to meet your body’s needs and help your body convert food into energy without interfering with lab testing.

Biotin also is found in many multivitamins, prenatal vitamins and dietary supplements. It has been aggressively marketed as a substance that improves hair, nails and skin and has also been touted as a weight-loss agent, with even less scientific support for that notion. A 5- to 10-milligram dose of biotin – an amount that’s commonly added to supplements – is 166 times to 333 times more than the 30 micrograms most individuals need in their daily diets.

Extra biotin causes false high results with some lab tests and falsely low results with others. Most of the published research on biotin interference focuses on hormone test interference, such as parathyroid hormone (PTH), thyroid-stimulating hormone (TSH), and T4 and T3 tests, as too much biotin in lab tests for thyroid hormone levels can lead to a false diagnosis of Graves’ disease, an autoimmune disease that causes too much thyroid hormone (hyperthyroidism) in children and adults. However, biotin in supplements can also affect tests for heart failure, pregnancy, cancer and iron-deficiency anemia.

As an example, there is a blood test to determine levels of troponin, which is a protein that indicates heart muscle damage has occurred. It is commonly ordered in an emergency room to find out if you might be suffering from a heart attack when you report you have chest pain. Unfortunately, troponin can be falsely low when large amounts of biotin are being used by the patient. The FDA has reported that a patient who was taking high levels of biotin died when a troponin test failed to show he was having a heart attack.

It can also interfere with testing for testosterone, estradiol and cortisol hormone levels. Investigators from the University of Minnesota recently reported results from an experiment in which study participants – all healthy adults – were asked to take 10 milligrams of biotin as a dietary supplement for a week. The investigators then tested the participants for nine different hormones, a cancer marker and iron levels, drawing blood before and after the participants took the biotin. The results were surprising even to the investigators: About 40 percent of the tests were thrown off by the supplements.

If you are taking supplements with biotin, it is strongly recommended that you discontinue the supplements one week before you have any planned blood tests OR inform your medical team what supplements or vitamins you are taking.

The FDA is taking steps to advise the general public that biotin is found in many over-the-counter supplements in levels that may interfere with laboratory tests. Examples include:

  • B-complex vitamins
  • Coenzyme R
  • Dietary supplements for hair, skin, or nail growth
  • Multivitamins
  • Prenatal vitamins
  • Vitamin B7 supplements
  • Vitamin H

There are many more, so check your vitamins very carefully for biotin levels and advise your healthcare team accordingly.