Study leader Declan Naughton of London's Kingston University and colleagues found red wine might reduce the amount of testosterone excreted by the body, which could distort the findings of urine drug tests.
Testosterone is a naturally occurring steroid hormone present in both men and women that can increase muscle mass, boost stamina and speed recovery, but athletes are prohibited from taking it, or a synthetic version of it, to gain a competitive edge, Naughton said.
"Previous research has shown the effect over-the-counter anti-inflammatory drugs can have on enzymes," Naughton said in a statement. "Since many of these drugs are derived from plants, we decided to look at the effect particular foods and beverages can have on enzymes involved in testosterone excretion. We chose green tea and then red wine because both have a huge variety of natural molecules and we wanted to see if they affected the amount of testosterone excreted in urine."
The study, published in the journal Nutrition, found a compound in red wine, quercetin, partially blocked the action of the enzyme UGT2B17, which looks for testosterone and then sends a message to the kidneys for it to be excreted.
Naughton stressed the research was conducted in test tubes and there were no human trials yet.