United States distance runner Shelby Houlihan has received a four-year ban from competition for failing a drug test.
In a statement on Instagram, Houlihan said her positive sample from a December drug test for the anabolic steroid nandrolone was due to pork in a burrito that she ate:
"I have since learned that it has long been understood by WADA [World Anti-Doping Agency] that eating pork can lead to a false positive for nandrolone, since certain types of pigs produce it naturally in high amounts. Pig organ meat [offal] has the highest levels of nandrolone.