This summer, tart cherry juice emerged as a popular choice during the Tour de France. Cyclists engaged in the three-week race throughout July were frequently seen taking supplements at the end of their daily rides.

In other sports, soccer players and tennis athletes have been noted for using pickle juice, while competitors from various events have turned to baking soda gels. These are just the latest wave of sports supplements capturing the spotlight. Yet, what benefits do they truly offer athletes?

Which supplements actually work?

Athletes across all levels frequently use supplements for a myriad of reasons. Professionals may rely on them to obtain high doses of essential nutrients in concentrated forms to support the substantial energy demands of endurance events.

For instance, creatine, a substance naturally produced in the body and found in protein-rich foods like meat, serves as a quick source of muscle energy. Some research indicates that athletes can take up to 20g of creatine daily to sustain their body’s reserves—equivalent to consuming about 4kg (8 pounds) of steak.

“In that sense, it should be taken as a supplement, as eating that much meat is quite impractical,” states Dr. Stephen Bailey, an expert in exercise physiology at Loughborough University in the UK.

Supplements can also enhance athletic performance. Bailey asserts that while athletes should prioritize nutritious diets, hydration, and optimized training, supplements can offer that extra edge when everything else is in place.

“In elite sports, the difference between winning and losing is often very slim,” he remarks. “If you’re excelling in every other area and seeking that slight improvement, [supplements] can potentially yield significant performance gains.”

Ketone drinks are becoming increasingly popular among elite endurance athletes aiming to gain a competitive edge. As the body converts fat to energy during prolonged exercise, it generates molecules called ketones, which serve as an alternative fuel source for muscles and the brain, alongside glucose, the body’s primary energy source.

“Ketones are there to supplement glucose levels,” explains Professor Kieran Clark, a biochemist at Oxford University.

Clark and her team developed a ketone drink that has been shown to allow professional cyclists to ride an additional 400m (1,300 feet) over an average span of 30 minutes compared to those consuming energy drinks rich in carbohydrates and fats.

Additionally, ketones may enhance cognitive function. At the end of a long day, Tour de France riders may struggle with strategic thinking due to low glucose levels.

“This is where [ketone drinks] can be particularly beneficial,” Clark notes.

Sports supplements may also aid in recovery post-competition. For instance, tart cherry juice exhibits anti-inflammatory properties.

“It’s an effective method for managing post-exercise inflammation,” Bailey states. “This could help alleviate pain.”

Challenges

Despite their potential benefits, a major issue with sports supplements is determining their effectiveness. While the market is saturated with various claims, many products lack rigorous testing.

“There’s significant financial motivation within the nutritional supplement industry,” notes Floris Wardenard, an associate professor of sports nutrition at Arizona State University. “Starting a supplement business is quite straightforward; nearly anyone can create a product without the necessary expertise.”

Even studies may be conducted on lab muscle cells, but not necessarily on human subjects.

A consensus statement from the International Olympic Committee (IOC) in 2018 identified just five supplements: caffeine, creatine, nitrate, beta-alanine, and sodium bicarbonate as supported for athletic performance. These were the only supplements backed by solid evidence demonstrating performance enhancement in specific scenarios.

Beyond concerns regarding effectiveness, the risk of contamination presents another challenge. Although supplements are treated as food in the UK, regulating their contents can be difficult (in the US, they face even less stringent regulations).

Consequently, impurities can be inadvertently introduced during manufacturing, and analyses of supplements have revealed banned substances like anabolic steroids in 14-15% of tested samples.

Athletes typically consume multiple supplements, increasing the risk of contamination. Even small quantities of banned substances across different products could accumulate, potentially resulting in positive doping tests and subsequent disqualifications.

“Utilizing a third-party testing organization is advisable to ensure that a supplement truly contains what an athlete is seeking as indicated on its label,” he advises.

Evolving Landscape

The question of whether certain substances in sports supplements should be banned remains ambiguous. The World Anti-Doping Agency (WADA), an independent international organization designed to combat doping in sports, prohibits substances meeting two of the following three criteria:

• Enhance sports performance
• Pose genuine health risks to athletes
• Contradict the principles of fair play

This list is reviewed annually to adapt to substances that are becoming more prevalent and potentially misused.

For example, caffeine was previously included on the WADA Prohibited List, but in 2004, its usage was reinstated for several reasons, including the view that its performance benefits were minimal and its widespread presence in food and beverages made regulation challenging.

Additionally, understanding how supplements affect athletes can be complex, as reactions differ among individuals. For instance, some may feel the effects of caffeine after one cup, while others require two or three.

Bailey highlights that the issue of personalized supplementation is gaining traction. Genetic testing techniques are being employed to examine how athletes’ genetic profiles influence their responses to nutrients and other dietary components.

Gender considerations are now influencing supplement recommendations. For example, varying amounts of carbohydrates and proteins are suggested for male and female athletes, along with inquiries into whether women require different supplements at various phases of their menstrual cycle or if the effects of contraceptives should be addressed.

As new formulations continue to emerge, athletes may increasingly benefit from improved supplement options. For instance, sodium bicarbonate (essentially baking soda) is commonly used to counteract lactic acid buildup, which causes fatigue during intense exercise. However, it can lead to gastrointestinal distress, including nausea and diarrhea. Many companies have started producing hydrogels that release baking soda more evenly throughout the gastrointestinal tract to mitigate this.

“Innovations in food technology are ongoing,” Bailey observes. “Sodium bicarbonate is currently prominent in elite cycling, and further research is needed to better understand its implications.”