Nutritional Outlook

Nutritional Outlook, Jan/Feb 2014

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■ NUTRITIONAL OUTLOOK 60 January/February 2014 Sports Digestion ease and efcacy are also key. Protein digestibility is most commonly mea- sured by a ratings system called the Protein Digestibility Corrected Amino Acid Score (PDCAAS). Burrows says isolated soy protein is the only vegetable protein whose PDCAAS score compares with animal proteins. Hemp is considered a slow-digesting pro- tein according to PDCAAS, says Richard Pierce, president of Canadian supplier GFR Ingredients. Last year, the company intro- duced a water-soluble hemp protein powder, HempSol-65, which it calls the most concen- trated hemp protein powder on the market. Te company manufactures out higher per- centages of hemp seed shell, which it says lowers carbohydrate levels and enables high- er protein content. Also, hemp has an 87% Biological Value (BV) score (a measurement of protein absorption), which Pierce says is lower than whey or rice's but signifcantly higher than soy's. Hemp is considered a com- plete protein, containing all nine essential amino acids. Nutralys pea protein is a "fast-intermedi- ate" digesting protein, says Roquette's Varde. He ranks it between whey and casein, with a digestion window of 20 minutes to 8 hours. Varde ofers other Nutralys numbers: 98% fe- cal digestibility, 89% gastroileal digestibility, and 78% postprandial nitrogen retention com- pared to other plant and dairy proteins. Pea is Vega's protein of choice for its plant- based recovery drink mix Vega Sport Re- covery Accelerator. "Pea protein supplies an easily digested source of BCAAs, which act as signaling molecules to transition muscles from a catabolic state (breaking down) to an- abolic (building up)" 5 —key for the product's recovery benefts, says Emma Cutfeld, Vega's innovation manager. (Sales of Vega products currently account for 30% of all plant-based protein sales in the U.S. natural channel, she says.) Designed for use in the 20-minute window immediately following a workout, Vega Sport Recovery Accelerator provides a specifc 4:1 ratio of carbohydrates-to-protein to enhance muscle glycogen synthesis and therefore muscle recovery 6 , she says. She adds that pea protein is more soluble for drinks than other plant proteins. Enzymes aid protein's amino acid release. "For sports, enzymes are being used in sever- al ways, which include nutrient delivery and energy metabolism, as well as post-workout recovery support. One interesting new trend is the use of proteases to release amino ac- ids more quickly, especially leucine," says Richard Mihalik, director of innovation and product development, National Enzyme Co. (NEC; Forsyth, MO). In vitro tests show that NEC's BioCore Edge enzyme blend breaks down whey protein quicker, reducing the size of protein molecules and speeding the release of BCAAs, he says. Plant proteins tend to release their amino acids more slowly compared to whey protein, so enzymes are important here if the goal is a quick release, Mihalik says. "Plant-based proteins have the most to gain from targeted protease blends like BioCore Edge," he says. Finding the right blend of proteases to make a specifc protein/protein blend diges- tion friendly requires knowing which amino acid bonds and sequences make the protein resistant to digestion. For instance, "less pro- cessed" plant proteins may have signifcant fatty acid and carbohydrate residue that makes digestion inefcient, Mihalik says. "Soy protein tends to be more resistant to our natural digestive enzymes, so adding ap- propriately selected proteases may acceler- ate the release of amino acids, making them more rapidly available for absorption," he adds. And proteases may act diferently on diferent protein sources. "Even proteins of the same type can behave diferently depend- ing on how a manufacturer processes them." Stacking Up the Science How do protein sources compare in muscle- building studies? Most comparison studies to date pit whey protein against soy. "When it comes to promoting muscle protein syn- thesis, whey protein almost always beats soy [in clinical studies]; soy has never beat whey protein," says Jose Antonio, PhD, editor-in- chief of the Journal of the International Society of Sports Nutrition. Whey protein came out on top again most recently in a 2013 Journal of the American Col- lege of Nutrition study 7 comparing the muscle protein synthesis efects of a 22-g supplement of carbohydrate, whey, or soy after resistance training in 63 young adults (aged 18 to 35). Compared to soy or carbohydrates, whey caused bigger gains in lean muscle mass (3.3. kg versus 1.8 kg for soy), as well as higher leu- cine levels in blood. Te researchers said the nine-month study is unique because it is the longest resistance-training study comparing protein sources, to date. Te Dairy Research Institute funded the study. "Because the research was conducted in healthy young adults as opposed to profes- sional athletes, the results have implications for a much larger demographic," Helwig says. Most other plant proteins lack compari- PDCAAS: On the WAy OUt? The Protein Digestibility Corrected Amino Acid Score (PDCAAS) has long been the preva- lent measure of protein digestibility. But that may change. "For nearly 20 years, the world has accepted PDCAAS as the method for measuring protein quality. However, a recent report by an Expert Consultation of the Food and Ag- ricultural Organization of the United Nations (FAO) has recommended a novel, advanced method that more accurately assesses protein quality be adopted," says Bryan Helwig, director of nutrition research for the Dairy Research Institute. That method is the Digestible Indispensable Amino Acid Score (DIAAS). According to Helwig, "DIAAS 9 overcomes limitations inherent in the PDCAAS scoring system regarding digestion and resultant availability of amino acids for use by body tissue. Additionally, DIAAS corrects errors in score reporting, thereby providing a more accurate protein quality score and allowing true comparison of protein quality between sources." Dairy protein comes out looking even better by DIAAS standards, by the way. Helwig says dairy protein may score up to 30% higher with DIAAS than with PDCAAS, according to the FAO committee report 9 . "The increased score is indicative of the higher-quality proteins found in dairy products, which is currently not refected in the PDCAAS equation," he says. ES385419_NO1401_060.pgs 01.30.2014 04:50 UBM black yellow magenta cyan

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