During a recent drug test, professional runner Shelby Houlihan tested positive for nandrolone, a type of anabolic steroid, and was banned from the Tokyo Olympics as a result. But Houlihan has an alternate explanation for her positive test: a tainted burrito.
“On January 14th, 2021, I received an email from the Athletics Integrity Unit (AIU), informing me a drug testing sample that I provided on December 15th, 2020, has returned as an Adverse Analytical Finding for an anabolic steroid called Nandrolone and that I am therefore subject to an immediate Provisional Suspension,” Houlihan explained in an Instagram post. “When I got that email, I had to read it over about ten times and google what it was that I had just tested positive for. I had never even heard of nandrolone.”
Since then, Houlihan said, she learned that certain pork products can potentially cause a false positive for nandrolone. “I put together a food log of everything that I consumed the week of that December 15th test,” she wrote. “We concluded that the most likely explanation was a burrito purchased and consumed approximately 10 hours before that drug test from an authentic Mexican food truck that serves pig offal near my house in Beaverton, Oregon. I notified the AIU that I believed this was the source.”
Houlihan, who previously competed in the Rio Olympics in 2016 and was gearing up for a promising showing in Tokyo, has since contacted experts, taken a polygraph test, and had a sample of her hair tested by a toxicologist, she said. The World Anti-Doping Agency (WADA) “agreed that test proved that there was no build-up of this substance in my body, which there would have been if I were taking it regularly,” Houlihan continued. “Nothing moved the lab from their initial snap decision.”
Finally, Houlihan received word last week that the Court of Arbitration did not accept her alternate explanation and instead banned her from the sport for four years, essentially sinking her chances of competing in the Tokyo Olympics this year. “I feel completely devastated, lost, broken, angry, confused, and betrayed by the very sport that I’ve loved and poured myself into just to see how good I was,” Houlihan said, adding, “I want to be very clear. I have never taken any performance-enhancing substances. And that includes that of which I am being accused.”
But can eating pork actually cause someone to test positive for nandrolone? Unfortunately, there isn’t an easy answer. “Nandrolone is not approved for use in any food animal,” Keeve Nachman, Ph.D., an associate professor at the Johns Hopkins Bloomberg School of Public Health, told NPR. In fact, using any steroids in pig production is illegal, Dr. Nachman said.
So the only (legal) way that the pork in Houlihan’s burrito could have caused a positive test result for nandrolone is if the steroid were naturally occurring, which is unlikely—but possible. There is some limited research to suggest that someone could test positive for that steroid in a urine test after eating tissue from a boar (noncastrated male pig). However, “the vast majority of the pork consumed in the U.S. does not come from boars,” Heather Fowler, Ph.D., director for producer and public health at the National Pork Board, told NPR.
That means Houlihan’s alternate explanation is not particularly likely, but also not entirely outside the realm of possibility. Other U.S. athletes, including Jarrion Lawson and Ajee Wilson, have had false-positive results overturned after proving they had eaten tainted beef. Houlihan could appeal the Court of Arbitration’s decision, but due to timing, she will still likely miss the Tokyo Games.