In November 2017, the Food and Drug Administration in the United States sent out an advisory to docs. At least one person had died because a heart attack was missed. Why? Because the biotin they were taking had led to a false lab result.
Biotin, also known as Vitamin B7 or Vitamin H, has become very popular because of the belief that it helps enhance the growth of hair, skin and nails. It’s involved in many important metabolic pathways in your body. The recommended daily dose is 30 micrograms per day. It’s found in egg yolk, pork, liver, whole cereals, soybeans, avocado, cauliflower and leafy greens. Deficiency is rarely seen because of how readily available it is in most North American diets.
There is evidence that it is useful for people with specific disorders involving the absorption of nutrients from their stomach, patients undergoing kidney dialysis who have muscles cramps, and some very specific inherited disorders of metabolism. The evidence for it helping to promote healthy hair, skin and nails is rather weak, but because the vitamin is water soluble it was thought that it wouldn’t be dangerous even at high doses because the excess would just be removed in your urine.
What wasn’t taken into account was the fact that there are a number of key lab tests where high levels of biotin in the blood will interfere with the results. That’s what we think happened with that patient who died. The lab wasn’t aware of the high levels of biotin in the blood sample, which led to a falsely low result for a marker of heart attacks. The test said no heart attack was happening when in fact it was.
The number of diseases affected are significant and range from thyroid and heart disease to anemia and certain cancers. What to do? Let your doctor known so that the lab can be informed. In some cases, there’s a doable work around or an alternative way to test. When that isn’t the case, you’ll want to stop your supplement at least one day before the blood is being drawn. If you’re consuming very high doses, it may have to be as much as a week. This highlights how important it is that your doctor know all the substances that you’re consuming whether prescription or over-the-counter or supplements.
Dr. Mitch Shulman is an Assistant Professor, Dept. of Surgery, McGill Medical School and an Attending Physician, Emergency Department, McGill University Health Centre. He’s also the CJAD AM 800 Medical Consultant.