By Lauren Swann, MS, RD, LDN
The Food Marketing Institute’s “2009 Grocery Shopper Trends” reports that 39% of consumers find protein to be important. A macronutrient needed for muscles, bones, hair, nails, skin, blood and a host of enzyme, hormone, immunity and metabolic processes, protein plays a key role in the body (namely, replacement and repair), and the body cannot internally produce the eight essential amino acids which comprise protein: isoleucine, leucine, lysine, threonine, tryptophan, methionine, valine and phenylalanine – all of which are vital daily requirements.
Most Americans tend to get plenty of protein in their diets. However, recent research described in the American Journal of Clinical Nutrition found that up to four out of 10 older Americans do not consume the recommended daily amount of protein, and this can contribute to muscle mass loss and function. For 70 million Americans 55 old or over, building and keeping muscle tone is vital, because deteriorating muscle mass and reduced strength can compromise an active lifestyle and contribute to many of the risks associated with growing older. While physical activity also plays a role, the latest research emphasizes the importance of diet and nutrition and the intake of proteins and amino acids critical to building and maintaining muscle mass.
Findings from metabolism researchers at the University of Texas Medical Branch at Galveston suggest that the best way to reduce muscle loss in the elderly as well as build muscle in general is through moderate amounts of protein at each meal. Their study results show that only about the first 30g -- just over 1oz of dietary protein -- consumed in a meal actually produces muscle, making this the muscle synthesis improvement “ceiling” per meal. Associate professor Douglas Paddon-Jones, senior author of a paper on the study published in the September issue of the Journal of the American Dietetic Association, said, “This suggests that muscle protein synthesis hits an upper ceiling, implying we need enough protein on board for efficient muscle-building during the day and don’t have to eat massive amounts of protein to maximize muscle synthesis, just have to apportion it.”
Aging consumers are not the only hot protein market. Datamonitor speculates that protein-enhanced exercise recovery drinks and similar healthy and active lifestyle beverages could be the next lucrative niche within the functional drinks category. “The Rationale for Consuming Protein Blends in Sports Nutrition,” a review by one supplier's global director of Sports Nutrition (Dr. Greg Paul) and published in a supplement accompanying the Journal of the American College of Nutrition, concludes that consuming a blend of proteins instead of just one type may have nutritional advantages to help promote recovery after exercise activity. Isolated soy protein, whey protein and casein have different digestion rates, potentially creating a "timed-release" effect that could prolong when absorbed amino acids are delivered to muscle, resulting in faster recovery. Comparative studies between isolated soy protein and whey protein show similar increases in lean body mass and that whey protein may have an advantage over casein. In addition, some consumers seem to prefer the taste of products that include a blend of proteins versus one type.
The possibility exists that endurance athletes, because of their specific needs, would benefit from a protein blend different than a blend used by strength athletes. Further research is needed to show the potential nutritional and performance benefits of different protein blends for specific segments of the sports nutrition consumer.
SIDEBAR: Proteins in Nutrition
By William A. Roberts, Jr., Business Editor
Manufacturers, following consumer interest (initially in low-carb dieting and, more recently, in health-related concerns), have increasingly touted the protein content of their foods. However, much remains to be learned about proteins. Measuring their quality, alone, can prove challenging, and recent research has delved into their respective efficacies and benefits.
Protein quality (simply put, how well any given protein is used by the body) can be measured with a variety of methods, though a quality rating can vary, depending upon the method employed. Further complicating matters, a protein’s quality is directly related to the physiology of the subject being studied. (Young, 1991) Nevertheless, the methods most often used to compare proteins are chemical score, biological value, protein efficiency ratio (PER) and protein digestibility corrected amino acid score (PDCAAS).
As the name suggests, chemical score evaluates a protein’s chemical composition; a protein is chosen as a reference, and other proteins are rated relative to that. A commonly used measure, biological value reflects the amount of nitrogen retained in the body divided by the amount of nitrogen absorbed from the tested protein. The PER method measures the amount of weight gained relative to the amount of protein consumed, so a PER of 2.5 would indicate the subject gained 2.5g of weight for every 1g of protein ingested. The newest measuring method, PDCAAS, is similar to the chemical score effort (in that it rates protein foods relative to a reference protein), but it also factors in the digestibility of a given protein. (ThinkMuscle.com)
While evaluating the efficacy of proteins has its obvious benefits, work is also being done to improve the acceptance of certain proteins. A recent study from Brazil, in fact, found spray-drying casein hydrolysates with gelatin and soy protein isolate (SPI) may help to reduce the bitterness of the protein hydrolysates. The effect was demonstrated by microencapsulating the protein hydrolysates in a mixture of gelatin and soy protein isolate. (Favaro-Trindade, 2009) The benefits of the procedure are widespread, noted the University of Sao Paolo researchers in the journal Food Hydrocolloids: they include low-cost, the incorporation of a process widely employed in the food industry, utilizing a water- and oil-compatible product, and the high nutritional value of soy protein.
The SPI:gelatin ratios tested for encapsulation included 50:50, 60:40 and 40:60. The mix overall was either 20 or 30% casein, with 80 or 70% of the SPI:gelatin mix. According to researchers, all of them “reduced the bitter taste (per a panel of 20 trained testers), the hygroscopicity and allowed controlled release properties of the casein hydrolysate.”
Reflective of consumers’ health concerns, another recent effort sought to discover whether whey protein hydrolysates (WPH) could be used as a source of whey-derived antioxidants. The WPH were prepared with four microbial proteases, and according to the Czech Republic researchers, “antioxidant properties were enhanced by hydrolysis in most of the cases,” with the Neutrase hydrolysates demonstrating the best antioxidant properties, as determined by ABTS assay measurement. (Dryakova, 2010)
Closely associated with those consumer health concerns has been an increased interest in weight control, an area where recent clinical efforts have evaluated proteins. Satiating and promoting less energy intake, proteins have a higher thermogenic effect (that is, energy expenditure) than carbohydrates or fat. Furthermore, some studies have shown that proteins have a favorable effect on body composition during weight loss and/or maintenance, helping to preserve fat-free mass, reduce fat mass and improve metabolic profile. (Westerterp-Plantenga, 2008)
In addition, research published in Obesity (Pal, 2009) evaluated dairy whey protein-- specifically, the possibility that it is the major dairy component responsible for the health benefits associated with increased dairy consumption. In the study, 70 men and women participated in evaluating the effects of whey protein supplementation on blood pressure, vascular function and inflammatory markers compared to casein and glucose (control) supplementation in overweight individuals. The researchers noted, “This study demonstrated that supplementation with whey protein improves blood pressure and vascular function in overweight and obese individuals,” including “significant” decreases in systolic blood pressure at week six and in diastolic blood pressure at week 12.
Pea proteins have been increasingly in vogue, and Maastricht University evaluated whey protein (WP), pea protein hydrolysate (PPH) and a WP/PPH combination in appetite, postprandial changes in hunger/satiety hormones and energy intake. The results found “some indications of lower hunger...desire to eat...and thirst...after consumption of PPH compared to MP or WP/PPH,” leading the researchers to conclude, “There was modest evidence with respect to satiety by PPH consumption.” (Diepvens, 2008)
Similarly growing in popularity has been hemp protein processed from Canabis sativa seeds. With a high protein content, hemp protein is also rich in amino acids, methionine and cysteine and a good source of arginine, which has a variety of vascular benefits.
Diepvens, K., D. Häberer and M. Westerterp-Plantenga M., “Different Proteins and Biopeptides Differently Affect Satiety and Anorexigenic/orexigenic Hormones in Healthy Humans,” International Journal of Obesity, March 2008.
Dryakova, A., et al., "Antioxidant Properties of Whey Protein Hydrolysates as Measured by Three Methods,” European Food Research and Technology, 2010;230(6):865-874.
Favaro-Trindade, C.S., A.S. Santana, E.S Monterrey-Quintero, M.A. Trindade, F.M. Netto, “The Use of Spray Drying Technology to Reduce Bitter Taste of Casein Hydrolysate,” Food Hydrocolloids, 10.1016/j.foodhyd.2009.10.012
Pal, Sebely and Vanessa Ellis, “The Chronic Effects of Whey Proteins on Blood Pressure, Vascular Function, and Inflammatory Markers in Overweight Individuals,” Obesity, November 5, 2009.
Westerterp-Plantenga, M.S., A.Nieuwenhuizen, D. Tome, S. Soenen and K.R. Westerterp, “Dietary Protein, Weight Loss and Weight Maintenance,” Annual Review of Nutrition, 2009, 29:21-41.
Young, V.R., “Soy Protein in Relation to Human Protein and Amino Acid Nutrition,” Journal of the American Dietetic Association, 1991, 91: 828-835.
Other Web Resources
* High-protein Diet Linked to AD
From the April 26, 2010, Prepared Foods E-dition