From The July 2001 Issue of Nutrition Science News

Winning Bar, Drink and Gel Ingredients

By Edmund R. Burke, Ph.D.

Although some dietary trends are losing steam, innovative sports nutrition supplements and foods are gaining momentum. Protein bars and drinks, energy drinks, and meal replacement powders are among the fastest-growing segments of the sports nutrition market. Whether the goal is to increase lean body mass, a refreshing and healthy energy boost, or a dietary supplement for busy days, product developers are striving to meet mounting demands.

A 2001 report by Nutrition Business Journal reports U.S. sales of sports nutrition products grew 12 percent in 2000 to reach $5.3 billion. Sports supplements—mostly protein powders, but also pills and single ingredients such as creatine—represent $1.6 billion; nutrition bars (some also used for weight-loss) $1.1 billion; and sports and energy drinks $2.6 billion. Sales are expected to jump from $5.3 billion in 2000 to $7.8 billion in 2004, or an annual average increase of 10 percent, with bars remaining the leading growth category, although not sustaining its 20-30 percent growth of the past couple years. NBJ's new report combines sports nutrition into a larger and gradually merging sports nutrition/weight-loss market, which amounts to $8.7 billion in 2000, as products and science converge and firms from sports nutrition markets branch into weight-loss and vice versa.

Protein Combinations
Bars and drinks once contained only casein as a protein source because it was inexpensive, plentiful, and easily obtained from suppliers. Then, whey became the protein of choice because the protein concentrations of whey are higher, more easily digested, absorbed faster, and more readily available than casein. However, it is significantly more expensive. Now manufacturers are combining proteins, such as soy and egg, for products that offer a complete amino acid profile and support consumers' varying digestibility levels.

Study results show that differences in amino acid delivery rates between whey and casein protein directly affect protein synthesis.² Whey increases the entry of amino acids into the circulatory system, increases protein synthesis, and does not change protein catabolism. On the other hand, casein enters the bloodstream more slowly, slightly increases protein synthesis, and is a marked catabolism inhibitor.³ The proteins were consumed without any other nutrients, including carbohydrates, which themselves can alter insulin secretion and, when combined with proteins, can have a synergistic effect. Also, the proteins were present in their native state and not partially predigested or hydrolyzed as are many protein-containing products now on the market.

Whey protein also contains an insulin-increasing higher proportion of branched chain amino acids (BCAAs) and a lower proportion of amino acids expected to stimulate glucagon release. Therefore, whey protein may promote a more anabolic hormonal environment than casein. However, no comparative clinical studies have examined the effects of whey and casein on insulin and glucagon.

Because casein is digested at a slower rate—although no studies have directly compared casein and whey protein digestion rates—it may make amino acids more available for protein synthesis and produce sustained elevations in blood amino acids, thereby reducing proteolysis, which is the hydrolysis of proteins into simpler substances. Additionally, the wide quality variability among whey protein supplements may diminish their intended effectiveness. Athletes need a positive nitrogen balance to promote muscle mass gains. To accomplish this, they need to maintain a constant supply of amino acids in the bloodstream to support a positive nitrogen balance. Therefore, a combination of whey and casein may be best for protein bars and drinks.

High-Protein Bars
The first ingredient in these bars is protein—usually more than 30 grams—and less than 20 grams of carbohydrates. They are often higher in calories (approximately 250) and size (as much as 3 ounces) than the traditional high-carbohydrate bar, and are made primarily for bodybuilders who want to increase lean body mass, rather than for dieters.

The protein generally comes from an ingredient blend, such as whey protein, hydrolyzed whey protein, casein, milk protein isolates, and soy protein. Few companies have conducted studies on their proprietary blends of proteins and other ingredients, such as growth factors and glutamine. However, two published studies tested protein's effect on healthy people in exercise programs.

One study was a randomized, prospective, 12-week trial of 38 overweight police officers, conducted at Brigham and Women's Hospital in Boston. Researchers found subjects gained more muscle mass and strength on their protein blend than they did on another manufacturer's protein supplement, but the measurements were outdated and inexact.⁴

In another study, conducted at the Exercise and Sports Nutrition Laboratory at the University of Memphis in Tenn., researchers used more exact measurements on the body composition of 51 college football players and found the same protein bar was no better than a high-carbohydrate supplement at increasing muscle mass and strength.⁵

A growing segment of the protein bar market is focused on soy protein bars. Soy entered the sports supplements arena within the past decade, first as a crude soy protein concentrate that lacked a quality amino acid profile and was high in sodium and carbohydrates. However, during the past few years, soy-protein extraction, concentration, and development processes have improved dramatically, with numerous high-quality soy protein products packaged as soy-protein isolates. These often are consumed to ensure adequate protein intake and to supplement caloric intake.

Protein Drinks
Manufacturers now offer whey protein powder formulations that are completely soluble in water. Whey protein products have improved taste and consistency, and a higher protein content than casein products. Whey protein drink flavor selections have been expanded beyond the standard chocolate and vanilla shakes, to include flavors such as tropical punch and banana colada.

Protein-based shakes, now available in cans, are commonly made with casein or with combinations of casein, whey, and other proteins. Up to 80 percent of most protein drinks' calories come from protein, with small amounts from carbohydrates, fats, and other ingredients. One protein ingredient worth exploring is the amino acid glutamine, which, if added in an efficacious dose, may provide muscle-protein synthesis and immune system benefits.⁶ Many bodybuilders try to get 15 grams of protein or more a day, with the addition of glutamine, and consistency-boosting and health-enhancing fiber. However, while glutamine has been shown to be important to cellular health, it is relatively unstable.⁷

Meal Replacement Powders
Is there a sports supplement that will decrease workout recovery time, boost your energy, and increase lean body mass? Some studies suggest this product is already available in the powder form. Meal replacement powders (MRPs) are typically low in calories (about 200 to 300 per serving) unless they are designed specifically for weight gain, in which case they may contain as many as 500 calories per serving. They generally contain a balance of 25 to 45 grams of protein, 15 to 30 grams of carbohydrates, and a few grams of fat, along with vitamins, minerals, and other nutrients.

When MRPs started gaining widespread popularity in the early 1990s, there was a lot of marketing hype with little scientific evidence to back it. Now, researchers are validating the health benefit claims of MRPs. For example, researchers in the Exercise and Sports Nutrition Laboratory at the University of Memphis conducted a study on the effects of meal replacement powders for football players at the university. During 84 days of winter training and spring practice, approximately 60 players supplemented their diet with either a carbohydrate placebo or an MRP, which also contained creatine. Results indicated that lean mass gains were significantly greater in the MRP group than in the carbohydrate group. Two similar MRPs were tested in this study, differing by the creatine, protein, carbohydrate, alpha-ketoglutarate, and RNA content.⁶

MRPs are useful for consuming high levels of high-quality protein without the saturated fat that often accompanies traditional protein-rich foods. They can be used to supplement other low-fat, nondairy sources of protein such as fish and poultry. Products differ in their protein sources, some of which may be better absorbed than others.

Deciding whether powdered food is right for your diet and/or athletic needs depends upon your goals. These drinks are ideal for the active person who cannot eat an optimum diet on a daily basis. By substituting an MRP and a piece of fruit for a high-calorie, high-fat meal, you can lower your calorie intake and eat more healthfully. Sports drinks also can be used postworkout, as well as throughout the day, to increase protein and calorie intake.

Energy Drinks
Energy drink manufacturers are targeting health-conscious American consumers interested in fortifying their diets with beverages that add ingredients such as B vitamins, minerals, carbohydrates, protein and antioxidants. Popularized as endurance athletes' energy-boosting beverages, they are shaking up the nonalcoholic beverage market.

This expanding industry is generating significant sales volumes, and generous margins for retailers. Energy-drink manufacturers are differentiating their products, not only through marketing and packaging, but also through an energy-boosting blend of ingredients. Guarana, caffeine, taurine, ribose, and ginseng, all of which are key ingredients in these drinks, have been studied for their effects.

Energy drink makers are true innovators in a market saturated with established soft-drink brands. The worldwide market for these products is considered by many analysts to be the next high-growth sector of the multibillion-dollar North American beverage industry. According to the Beverage Marketing Corporation, based in New York City, the energy-drink segment is poised for continued rapid growth and competition.

The Bottom Line
The demand for protein bars and drinks, MRPs, and energy products is driven by athletic and fitness enthusiasts who seek products that provide energy, and complete nutritional profiles, along with strength- and body mass-producing ingredients.

Edmund R. Burke, Ph.D. an exercise physiologist at the University of Colorado, Colorado Springs, is author of D-Ribose: What You Need to Know (Avery, 1999) and Optimal Muscle Recovery (Avery, 1999).

References

1. Liebman B, Schardt D. Nutr Action Newsletter 2000 Dec:10.

2. Boirie Y, et al. Slow and fast dietary proteins differently modulate postprandial accretion. Proc Nat Acad Sci 1997;94 (26):14930-5.

3. Dangin M, et al. The digestion rate of protein is an independent regulating factor of postprandial protein retention. Am J Physiol 2001;280:E340-8.

4. Demling R, DeSanti L. Effect of a hypocaloric diet, increased protein intake and resistance training on lean mass gains and fat mass loss in overweight police officers. Ann Nutr Metab 2000;44(1):21-9.

5. Kreider RB, et al. Effect of nutritional supplementation during off-season college football training on body composition and strength. JEPonline 1999;2(2). (www.css.edu/users/tboone2/asep/aprilr.htm).

6. Antonio J, Street C. Glutamine: a potentially useful supplement for athletes. Can J App Physiol 1999;24:1-14.

7. Keast D, et al. A simple bacterial bioassay for the measurement of L-glutamine. Ann Clin Biochem 1998;35:110-4.

8. Kreider R, et al. Effects of ingesting supplements designed to promote lean tissue accretion on body composition during resistance training. Int J Sport Nutr 1996;6:234.

9. Baum M, Weiss M. The influence of a taurine-containing drink on cardiac parameters before and after exercise measured by echocardiography. Amino Acids 2001:20(1):75-82.

10. Horne JA, Reyner LA. Beneficial effects of an "energy drink" given to sleepy drivers. Amino Acids 2001:20(1):83-9.