This is a very good question and one that has gained a lot of interest from the scientific community over the past ten years. Scientists have proven that consuming carbohydrates and protein after high intensity workouts reduces recovery time by replenishing glycogen stores and protein for muscle repair. This has led to the interest in studying whether or not carbohydrate and protein consumption during exercise increases performance by much of the same mechanisms found in post workout recovery.
Multiple studies have been conducted comparing ergogenic nutritional aids containing carbohydrates (CHO) against carbohydrate and protein (CHO:N) aids. Several of these studies demonstrated CHO:N drinks exhibit greater athletic performance or energy output than CHO drinks alone, while other studies concluded no significant difference between the two. More importantly, however, none of the studies conducted showed CHO drinks providing greater performance than CHO:N drinks over long periods of high intensity training. The mechanisms behind CHO:N drinks have been hypothesized and researched with limited conclusive information. To reach this conclusive information, several scientific challenges need to be addressed including how the studies are designed, measured, and statistically proven, which are sure to be focuses in the future of sports nutrition.
The science driving the interest in CHO:N drinks consumed during endurance training stems from information widely accepted by sports nutrition experts, biochemists, and food scientists around the world. This information focuses on five key concepts starting with protein consumption. As protein passes through the stomach partially digested and enters the intestinal tract, proteolytic enzymes cleave peptide bonds yielding short chain amino acids that increase fluid transport through epithelial cells carrying electrolytes and other key nutrients to their absorption sites. The end result is an efficient nutrient delivery system. Next, protein provides precursors through a series of reactions responsible for increasing Krebs cycle intermediates. These intermediates are critical for mitochondrial energy production, which often become depleted in the absence of protein. Another hypothesized benefit to consuming protein includes elevated branch chain amino acids (BCAAs) that compete for the same absorption site as L-tryptophan, a precursor to seratonin production. Without BCAAs, L-tryptophan can readily cross the blood brain barrier and cause exercise induced fatigue. The fourth benefit to consuming CHO:N drinks is the consistent increase in plasma insulin, which sustains blood glucose levels and prolongs the depletion of glycogen stores in the liver and skeletal muscle. Finally, as you continue to exercise, your body will eventually resort to protein taken from muscle tissue to be used as energy. As an endurance athlete you want to maintain nitrogen balance through protein consumption, otherwise your body will have a negative nitrogen balance leading to muscle catabolism as opposed to muscle anabolism.
Not all protein sources are created equally. The quality of whole food protein sources are critical when consuming a CHO:N drink. The more bioavailable, the better the protein source. Whey protein isolate (WPI) and egg albumen are by far the most readily absorbed proteins available. Ranking the highest among various protein scores including Protein Digestion Correct Amino Acid score (PDCAA), Biological Value (BV), and Protein Exchange Ration (PER), these proteins are preferable compared to other proteins or free form amino acids. It is important to use WPI versus whey protein concentrate (WPC) due to the filtration process used to isolate the protein and remove unwanted impurities such as lactose and fat. WPC can contain 10 to 30% lactose and up to 10% fat, whereas WPI contains <1% of both lactose and fat. WPI is rich in BCAAs and is quickly absorbed by the body. Egg albumen, like WPI, also contains high levels of BCAAs and has a long history of use by athletes. This purified protein is a complete protein with all of the essential amino acids and also contains sodium and potassium as beneficial nutrients. These proteins are efficiently broken down by proteolytic enzymes into highly absorbable di and tri peptides. Two thirds of all protein absorbed by the body are in di and tri peptide forms compared to free form amino acids. Free form amino acids, especially BCAAs are derived from chemical synthesis developed by scientists using chicken feathers and human hair. The body may not recognize these forms, decreasing their bioavailability compared to amino acids contained in whole food sources such as Whey Protein Isolate and Egg Albumen. Free-form amino acids increase the osmolality of a sports drink solution, which in turn results in reduced utilization and absorption of other key nutrients. The bottom line here is that whole proteins are preferable to free-form amino acids, and pure, highly filtered forms of whole proteins are the most optimal when used as components of a sports drink.
Taking these scientific facts into consideration along with multiple studies indicating CHO:N drinks provide higher energy output, do you want to continue believing protein is for recovery, or know this combination is on the horizon in sports nutrition? Let trial and error be the judge and what works for you, the athlete.
This article was written and submitted by the science team at UR. To learn more about UR and all their products visit: http://www.ur-theanswer.com/