Sports nutrition has become big business on the back of star ingredients, such as whey, creatine and antioxidants. Mark Tallon, PhD, visited the American College of Sports Medicine conference in San Francisco to find out more

The sports nutrition industry has expanded beyond its non-commercial roots into a $2 billion a year growth market. With revenue sales of sports supplements projected to reach in excess of $4.5 billion by 2007, research-proven, effective products are hot property. For those keen to take advantage of this booming sector, the 50th American College of Sports Medicine (ACSM) annual meeting was the place to be. At the five-day conference in San Francisco, industry professionals, researchers and food technologists presented the latest sports supplementation research and assessed the impact it may have on the dietary food industry over the coming year.

Protein Pluses
In the late 1960s, carbohydrate-loading, as a way to optimise muscle glycogen stores and enhance endurance performance, heralded the concept of sports nutrition as a commercially adaptable discipline.¹ Since then, the use of protein-fortified foods has become increasingly popular with people interested in exercise, health and weight-control. With the advent of the Atkins diet in the US, which preaches increased protein intake, the search for clinically validated product-claims for the protein-centric market cannot be undervalued. The estimated total whey protein supply market was valued at $470 million in 2002 and is set for further growth in 2003.²

It is clear from the sheer volume and quality of protein studies presented at the ACSM conference, as well as the interest shown, that protein metabolism is becoming a dynamic research field in its own right. In particular, new findings demonstrate the benefits of whey protein for the health of the general population and athletic performance.

"There is mounting scientific evidence on the health benefits of whey protein; it is only a matter of time before sufficient data is available to make product-related health claims, both in Europe and the US," said Robert Child, PhD, who unveiled a study showing whey-improved biochemical markers of oxidative cell damage and reduced muscle fatigue.³ "This will invariably lead to a consumer-led expansion in the sale of whey-based products in 2003 and beyond."

Paul Cribb, a researcher from Victoria University, Australia, and director of AST Sports Science (which funded the study), investigated the effect of combining creatine and whey on muscle fibre growth, body composition and strength. During 11 weeks of resistance training, the creatine and whey supplemented group had larger gains in lean mass and strength than in the creatine and carbohydrate, whey, or creatine-alone groups.⁴

Interestingly, the addition of whey to creatine resulted in a smaller increase of creatine uptake than in most traditional creatine studies. The reason for this is unknown, but many of the compounds in whey may be carried on the same sodium-dependent transporters as creatine, leading to a state of competitive inhibition. A second possibility may be that there is a limited capacity for the storage of amino acids and related metabolites, and if whey isolates elevate intracellular glutathione concentrations, then there may be an accompanying loss of storage capacity for creatine in skeletal muscle. But this is currently speculation and requires further research.

The highlight of the protein conference was a mini symposium on skeletal muscle protein metabolism and nutritional supplementation sponsored by Colorado-based Experimental Applied Science (EAS). Dr Mark Tarnopolsky and Dr Martin Gibala concluded that individuals with a sufficient dietary intake, around 1.8g/kg protein (or 127.6g/day—about 4 1/2 ounces—for an average male), would have no need for supplemental protein intake. Dr Tarnopolsky concluded that anything beyond this intake level is simply oxidised and excreted. Nevertheless, EAS president and director of science Dr Christine Steele said, "The research findings confirm the protein needs for individuals engaging in a strenuous exercise programme."

Creatine Monohydrate And Beyond
The saviour of the sports supplement market, creatine, was once again a headliner, although the number of publications were not as prolific as in previous meetings. This year saw the emergence of 'creatine plus ingredient X', which may spawn products that are commercially viable in their own right.

Professor Roger Harris, a researcher in both creatine and carnosine, commented on the latest potential of L-carnosine: "The use of beta-alanine to increase muscle carnosine (reported at the April meeting of the Federation of American Societies for Experimental Biology in San Diego) offers a means to increase anaerobic exercise potential and, as reported at the ACSM meeting, is likely to be an additive to any effect of creatine in some exercise conditions."

In one human study, combining creatine monohydrate with beta-alanine increased maximum power output during the first minute of maximal dynamic exercise, probably as a result of increased hydrogen ion buffering by elevated muscle carnosine concentrations.⁵

Researchers in several studies have found that the herbs ginseng and astragalus reduce blood lipid levels in animal models; however, little is known about their influence in humans. In one ACSM study, researchers combined creatine with a botanical extract of ginseng and astragalus in resistance-trained older adults. Researchers found significant decreases in lipid levels in the creatine/botanicals group, but no difference in either the creatine or the placebo groups.⁶ This suggests that these botanicals may have a role in lowering cholesterol levels in combination with resistance training. What is not known is whether it was the combination of creatine and botanical extracts or the extracts alone that produced the effects.

Radical Antioxidants
This year's conference was a dream come true for free radical biochemists. The invited speakers list was a 'who's who' in the antioxidant field, including Drs Chanden Sen, Malcolm Jackson, Scott Powers and Li Li Ji, to name but a few.

The antioxidant market is worth approximately $440 million per year. However, the complexity and large volume of dietary supplements claiming antioxidant status have left the public in a state of confusion and sales in decline. Rather than list any particular study, it would be more prudent to highlight the main points from the studies presented at the conference in a bid to clarify many of the misconceptions regarding antioxidants.

Vitamin C and sodium: Vitamin C is the most concentrated vitamin in plasma and benefits from one of the largest bodies of research literature of all antioxidants. Dr Golfarb, one of the chairs of the antioxidant sessions, reiterated the importance of taking vitamin C with sodium because transport of vitamin C in the gut is sodium-dependent (protein isoforms SVT1 & SVCT2).⁷ This recommendation may be more applicable to older populations as these protein transporters are down-regulated with age, making bioavailability a key in the maintenance of vitamin C uptake.

Medicinal and cosmeceutical applications: Levels of selenium in plants and grains can vary considerably since EU directives dictated the use of European rather than North American wheat. Since this EU remit, there has been a marked fall in selenium intake in Europe. Concerns regarding deficiency have been raised and the current dietary intake of selenium of 39mg/day is approximately 50 per cent of the recommended daily intake (RNI).⁸

Professor Malcolm Jackson, from Liverpool University's department of medicine in the UK, presented data on the ability of subjects to rid themselves of a flu virus, with and without selenium supplementation.⁹ Subjects who supplemented with selenium (2 to 3 times the RNI) were able to rid their bodies of the virus significantly faster than the non-supplemented subjects.

This study has many important implications. In addition to selenium's role in glutathione peroxidase metabolism, it has now been shown that selenium is also vital for optimal functioning of the immune system. These findings have broad-based implications and indicate that the current RNI for selenium is not high enough and may require revision.

Vitamin E sunscreen: A study finding vitamin E reduced UVR damage in cultured skin cells may have some implications for the cosmeceutical industry.¹⁰ Professor Jackson commented, "It is conceivable that antioxidants could positively impact UV-induced free radical damage, if a transdermal liposome delivery system can be used effectively. Whether this would be more beneficial than a UV-blocking cream is unknown."

Expanding The Category
The real take-home point for manufacturers attending the conference was to optimise antioxidant supplementation rather than using the blitz approach incorporated by many nutrition companies. The need for oxidants/free radicals within any living system is vital to cell signaling, as this leads to natural elevations of antioxidant capacity and serves as a stimulus for growth and adaptation. During the next year, we will start to see a big change in the way antioxidants are marketed and formulated, as consumers become aware of this latest scientific data.

The research from this year's ACSM meeting will no doubt be integrated by food technologists and branding specialists into convenient delivery systems for use in weight loss and body augmentation markets ­ and not simply reserved for the sports elite as implicated under the title sports nutrition. If the insights gained from the excellent research presented at this year's conference are correct, the growth of this sector of the nutrition industry will penetrate a wider selection of consumer markets as the education behind the potential medicinal and health benefits are disseminated.

Mark James Tallon, PhD, is CEO and chief science officer of Oxygenics Ltd, a nutritional consulting firm based in the UK. [email protected] www.OxygeniX-Consultancies.com

References

1. Bergstrom J, et al. Diet, muscle glycogen and physical performance. Acta Physiologica Scandinavica 1967;71:140-150.

2. Rea P. Natural Products Expo West, Nutrition Business Journal, Anaheim, USA 2003 March.

3. Child RB, et al. Physiological and biochemical effects of whey protein and ovalbumin supplementation in healthy males. Med Sci Sport Ex 2003 35 (5): abstract 1497.

4. Cribb P, et al. The effects of whey isolate, creatine and resistance training on muscle fibre characteristics, strength and body composition. Med Sci Sport Ex 2003 35 (5): abstract 2239.

5. Harris RC, et al. Effect of combined b-alanine and creatine monohydrate supplementation on exercise performance. Med Sci Sport Ex 2003 35 (5): abstract 1206.

6. Hannmer S, et al. Effects of ginseng/astragalus botanical extracts and creatine on cholesterol levels in resistance-training older adults. Med Sci Sport Ex 2003 35 (5): abstract 1208.

7. Liang WJ, et al. Vitamin C transport systems of mammalian cells. Mol Membr Biol 2001; 18(1):87-95. Review.

8. Tuula E. The role of chromium, selenium and copper in human and animal metabolism. J Orth Med 1995 10 (3 & 4): 149-164.

9. Jackson M. Dietary antioxidant health and exercise 50th Annual meeting of the American College of Sports. Medicine San Francisco, USA 2003 May.

10. Jones SA, et al. Effect of antioxidant supplementation on the adaptive response of human skin fibroblasts to UV induced oxidative stress. Redox Rep 1999; 4(6): 291-9.