An increasing amount of scientific evidence indicates that whey proteins can help with weight-management goals and promote better body composition and building of lean muscle, particularly when combined with resistance exercise. Further, whey protein is one of the best sources of branched-chain amino acids, especially leucine, which can help rebuild muscle protein following exercise. Muscle breaks down during exercise; consuming whey protein after exercise can help speed the rebuilding of muscle by increasing muscle synthesis.
“Bodybuilders have long known the benefits of whey protein for muscle strengthening and recovery,” says Burrington. “But now, research shows all active people can benefit from this dairy-based ingredient.”
In a study using eight resistance-trained athletes, the Exercise Metabolism Research Group with the Department of Kinesiology at McMaster University, Hamilton, Ontario, part of the National Research Council in Canada, found that participants who ingested a carbohydrate drink containing 10 grams of whey protein with 21 grams of fructose following resistance exercise saw a rise in muscle protein synthesis.
“Formulators will find whey protein isolate (WPI) is very easy to work with, partially due to its high solubility, and its unique ability to remain clear at the low pH range of 2.8 to 3.5 found in high-acid beverages, such as isotonics,” Burrington says. “Due to this clarity and solubility, formulators can pack more protein into a beverage drink than with soy protein, which is not as soluble as whey protein below pH 3.9.”
WPIs are a high-quality concentrated source of dairy whey protein (more than 90%). They also have less than 1% lactose and possess a neutral flavor that allows addition into beverages not normally associated with dairy. A hydrolyzed version is available if more heat stability is desired.
Soy protein, a common base for meal-replacement beverages and bars, is not typically associated with energy or endurance drinks. However, a hybrid beverage formulation from Reliv International Inc., Chesterfield, MO, combines soy protein and other nutrients in a powdered drink mix. The company provides clinical data associating soy protein intake with increased energy, endurance and lean muscle mass; and decreased length of recovery after exercise.
The performance-enhancing drink “meets the needs of physically active people with a balance of nutrients formulated to improve performance, endurance, recovery and repair,” says Carl Hastings, chief scientific officer, Reliv International. Each serving delivers 13 grams of muscle-building soy protein, as well as energy- and endurance-providing and fat-burning ingredients, such as medium-chain triglycerides (MCTs), creatine and coenzyme Q10 (CoQ10).
One soy protein isolate ingredient offered by Burcon NutraScience Corporation, Vancouver, is suited for sports drinks, according to the manufacturer. Because it is easily dispersed and dissolved, 100% soluble, and is completely transparent in solutions, it could be added as a protein source to powdered beverage mixes, whether conventional canisters or single-shot sleeves. It would be an option
instead of whey protein for the lactose intolerant.
Another protein source gaining attention from sports and energy enthusiasts comes from eggs. Though egg products are more likely to be formulated into bars than beverages, ongoing research may change this innovation focus.
A recent research review published in Nutrition Today (Jan./Feb. 2009; 44(1):43-48) affirms that the high-quality protein in eggs makes a valuable contribution to sports nutrition. The protein in eggs provides steady and sustained energy because it does not cause a surge in blood sugar or insulin levels, which can lead to a rebound effect or energy “crash” as levels drop, according to Donald Layman, co-author of the research review and professor emeritus, Department of Food Science and Human Nutrition, University of Illinois, Urbana-Champaign. “Eggs are a nutrient-rich source of high-quality protein and provide several B vitamins required for the production of energy in the body,” he says.
Carbohydrate complexity
As mentioned, carbohydrates are the primary source of caloric energy in sports and energy drinks. “Carbohydrate-loading beverages for pre-exercise/competition consumption should be easy to digest,” says Tonya Armstrong, senior applications scientist, Grain Processing Corp., Muscatine, IA. “Maltodextrins have been very successful in this category, because they can be consumed at very high levels without upsetting the stomach.”