Athletes have been known to take sports supplements as part of a strategy to boost their performance and give them an edge over the competition.

Many studies have shown dietary ingredients can safely and effectively aid sports performance by increasing energy, weight management and muscle development.

Unfortunately, potentially dangerous ingredients are sometimes found in illegal products that label themselves as supplements, endangering professional athletes and jeopardizing their reputation.

During 2014 Winter Olympics in Sochi, Russia, two athletes were disqualified from the games after they tested positive for the controversial stimulant dimethylpentylamine (DMAA), an ingredient that had been found in U.S. dietary supplements until a recent FDA warning.  Although the Olympic athletes Eva Sachenbacher-Stehl of Germany and William Frullani of Italy denied intentional wrongdoing, both said they took dietary supplements.

From 2008 through 2013, FDA flagged 340 supplements—including bodybuilding, erectile dysfunction and weight-loss products—that were "tainted" with concealed drugs and other dangerous chemicals. Sexual enhancement, weight loss and muscle-building products comprise more than 90 percent of the more than 400 products that are listed in FDA's tainted supplements database, according to Robin Koon, executive vice president of Best Formulations, a contract manufacturer of nutritional supplements.

The Federal, Food Drug & Cosmetic Act (FD&C) defines "adulterated" dietary supplements as products or ingredients that present "a significant or unreasonable risk of illness or injury" under ordinary conditions of use or those conditions of use that are recommended or suggested in the labeling.

A manufacturer's failure to test ingredients for adulterated substances could result in regulatory and legal consequences, including a citation on a Form 483, a warning letter or even a criminal prosecution. The FD&C provides for criminal misdemeanor penalties in connection with the sale of an adulterated food. Such criminal prosecutions have been brought sparingly and largely or entirely been limited to widespread occurrences of foodborne illness, such as the fatal Listeria outbreak tied to Jensen Farms' cantaloupes in Colorado.

While adulteration of sports supplements remains a problem for the industry, supplement manufacturers and marketers can limit their exposure to spiked ingredients by strictly following cGMPs (current Good Manufacturing Practices), employing testing methods that are even more thorough than current FDA regulations require, and participating in auditing and certification programs like those offered by NSF International.

For more on sports supplements, read INSIDER's Sports Nutrition Digital Issue, "Making the Cut."