WEDNESDAY, Aug. 16 (HealthDay News) -- Two company-funded studies offer differing views on the benefits of adding protein to everyday sports drinks.

One Canadian study, sponsored by the makers of Gatorade, found that adding protein to sports drinks does not improve exercise performance.

"Sports drinks improve performance during prolonged exercise because of two key ingredients: carbohydrate, which provides fuel for working muscles, and sodium, which helps to maintain fluid balance," researcher Martin Gibala, an associate professor of kinesiology at McMaster University in Hamilton, Ontario, said in a prepared statement.

"Research also supports the practice of consuming protein after exercise to promote muscle recovery. However, the alleged benefits of consuming protein during exercise is controversial," he added.

The study included 10 trained cyclists who, on three occasions, did a simulated 80-kilometer (50-mile) race. During these sessions, the cyclists were given either a sports drink, a sports drink with protein, or a placebo that provided no energy.

Compared to the placebo, the sports drink improved performance. The sports drink with protein was no more beneficial than the regular sports drink, the researchers said.

"Our study shows that protein confers no performance benefit during 'real-life' exercise when athletes consume sufficient amounts of sports drink," Gibala said.

The findings were published in the August issue of the journal Medicine & Science in Sports & Exercise.

However, another study -- funded this time by the makers of the protein-rich Accelerade sports drink -- found that the drink rehydrated endurance athletes better than Gatorade or water.

Gatorade contains carbohydrates plus electrolytes, whereas Accelerade (made by PacificHealth Laboratories) contains those two elements plus protein.

The athletes in the study lost approximately 2.5 percent of their body weight through exercise-induced sweat loss, according to researchers at St. Cloud University in Minnesota. Those taking Accelerade rehydrated at rates that were 15 percent better than athletes taking Gatorade, and 40 percent better than those drinking plain water.

The study is published in the August issue of the International Journal of Sport Nutrition and Exercise Metabolism.

More information

The President's Council on Physical Fitness and Sport has more about sports nutrition.