Title: Nutrition and Professional Football
Key words: optimal nutrition, training, fitness, diet, nutrition, metabolic acidosis, hydration level, circadian rhythm, jet lag, hypoglycaemia, glycogen depletion, dehydration, vitamins, minerals, antioxidants, essential fatty acids, hyperhydration, creatine, glutamine
Date: Aug 2000
Category: 12. Sports
Author: Dr van Rhijn
Nutrition and Professional Football
Football is a very demanding sport, played during long seasons in rapidly variable climates and time zones, where gruelling training and match schedules allow little recovery time between performances. Optimal nutritional support is central to maintain performance, fitness & body composition, prevent fatigue & injury and aid recovery & health for professional squads1. This paper addresses the scientific evidence for nutritional strategies.
General Causes of Fatigue
Fatigue affects performance adversely and is dependent upon the individuals status on training, fitness, diet, nutrition, metabolic acidosis, hydration level, circadian rhythm, jet lag and external environmental factors such as temperature, altitude and humidity. Other health issues may undermine fitness and contribute to fatigue such as gut dysbiosis, food intolerance, allergies, low-grade infections, mood states and homesickness. Match fatigue is mainly due to hypoglycaemia, glycogen depletion2 and dehydration.
Practical nutritional interventions are required to establish healthy habits that meet all the nutrient requirements to minimise fatigue, maintain hydration, promote recovery, growth and development3. Players must be thoroughly assessed4, including their dietary5 and fluid intakes and monitored throughout the season. Strategies are adapted according to events i.e. training, match play, rest, recovery, injury, season and different requirements whilst travelling. Encourage wide variety, highly nutritional value foods (fruit / vegetables / fatty fish) to provide vitamins, minerals, antioxidants and essential fatty acids. The verdict regarding ergogenic aids is still out for most supplements, but players risk low intakes of Zn, Mg, Ca6 and B-group vitamins7 to warrant supplementation with antioxidants8, despite compensatory biochemical adaptation to severe exercise9.
Football is a high intensity, intermittent activity requiring short-term, repeated, explosive bursts of maximum effort with short recovery periods in between. Many players struggle to keep their weight between matches despite a recommended daily energy intake of 14-15 MJ/day, generally obtained from CHO (8-10g/kg/day [60-65%])10, Protein (1.4-1.7g/kg/d [12-15%])11 and Fat (1.7-2.5g/kg/day [20-30%])12,13. CHO conversion into muscle glycogen is essential to provide strength, endurance, intensity14, speed, saturated stores and to delay lactate build-up and fatigue, thereby enhancing recovery15.
Fluid losses from sweating can be enormous16 and depend on environmental temperature (1.5L [10-150C] to 3.5-4L [30-380C])17. Dehydration impairs performance18 by reducing thermal dissipation19, muscular endurance & strength and causes muscular cramps, exhaustion, heat stroke, coma and death if extreme. Minimum requirements are 2-2.5 L/day and hydration can be monitored by weighing and urine analysis.
Creatine, a nitrogen compound synthesised from amino acids and stored in skeletal muscle (95%) as phosphocreatine (PCr)20, benefits competitors participating in sports requiring short-term21, repeated22, explosive bursts of maximum effort. It enhances peak performance23,24, endurance capacity25, total work output26 and delays or prevents fatigue27 by providing APT for the immediate ATP-CP phosphagen energy system28. Glutamine, a conditionally essential amino acid is reduced in muscle stores during strenuous sport activity29. It is essential in improving immunity30,31,32, maintaining gut integrity33 and regulating protein turnover34 (nitrogen donor).
Nutritional Strategies During Match Play
More emphasis is placed on CHO and hydration than protein and fat fish meals during matches to enhance performance. Low bulk, high complex CHO (12-13g/kg/day) is required, divided in pre-match (1-4 hours) loading (fill glycogen stores35), and post match refuelling36. Significant performance ergogenic benefit is obtained from CHO beverages during prolonged exercise37,38, especially in glycogen compromised individuals39. Hyperhydration (personal water bottles), ideally in the form of isotonic sport drinks40, should be encouraged (500ml pre-match and 500-800ml at ½ time) to replenish losses and also enhance performance41 and endurance42. Post-match rehydration is essential43, but avoid hypertonic solutions, which delay gastric emptying44 and promote dehydration45,46.
Proper, professional nutritional support, tailored to the individual, is essential to ensure peak fitness and health during the demanding season. There is too much at stake to be negligent about the increasing science behind nourishment.
1. Shepherd, R.J. Biology and Medicine of Soccer: an update. J. Sports Sci., 1999; 17,10: 757 786.
2. Reilly, T. Energetics of high-intensity exercise (soccer) with particular reference to fatigue. J. Sports Sci., 1997; 15:3, 257 263.
3. Burke, L. Practical issues in nutrition for athletes. J. Sports Sci., 1995; 13, S83 S90.
4. Kirkendall, D.T. Effects of nutrition on performance in soccer. Med. Sci. Sports Exerc., 1993; 25:12, 1370 1374.
5. Sobal, J. & Marquart, L.F. Vitamin/mineral supplement use among athletes: a review of the literature. Int. J. Sport Nutr., 1994; 4:4, 320 334.
6. Rico Sanz, J. et al. Dietary and performance assessment of elite soccer players during a period of intense training. Int. J. Sport Nutr., 1998; 8:3, 230 240.
7. Economos, C. D. et al. Nutritional practices of Elite Athletes. Sports Med., 1993; 16, 6: 381 399.
8. Maughan, R.J. Role of micronutrients in sport and physical activity. Br. Med. Bull., 1999; 55:3, 683 690.
9. van der Beek, E. Vitamin supplementation and physical exercise performance. J. Sports Sci., 1991; 9: 77 89.
10. Bangsbo, J. Energy demands in competitive soccer. J. Sports Sci., 1994; 12 Spec No: S5 - S12.
11. Lemon, P.W. Protein requirements of soccer. J. Sports Sci., 1994; 12 Spec No: S17 - S22.
12. Clark, K. Nutritional guidance to soccer players for training and competition. J. Sports Sci., 1994; 12 Spec No: S43 - S50.
13. Hawley, J.A. et al. Nutritional Practices of Athletes: Are they Sub-Optimal? J. Sports Sci.,, 1995; 13: S75 S87.
14. Balsom, P.D. et al. Carbohydrate intake and multiple sprint sports: with special reference to football. Int. J. Sports Med., 1999; 20: 48 52.
15. Fallowfield, J. & Williams, C. Carbohydrate Intake and Recovery from Prolonged Exercise. Int. J. Sports Nutr., 1993; 3: 50 64.
16. Brouns, F. Heat-sweat-dehydration-rehydration: a praxis orientated approach. J. Sports Sci., 1991; 9, 143 152.
17. Burke, L.M. & Hawley, J.A. Fluid balance in team sports. Guidelines for optimal practices. Sports Med., 1997; 24:1, 38 54.
18. McGregor, S.T. et al. The influence of intermittent high intensity shuttle running and fluid ingestion on the performance of a soccer skill., J. Sports Sci. 1999; 17:11, 895 903.
19. Elias, S.R. Team sports in hot weather: guidelines for modifying youth soccer. Physic. Sports Med., 1991; 19: 67 80.
20. Jacobs, I. Dietary creatine monohydrate supplementation. Can. J. Appl. Physiol., 1999; 24:6, 503 514.
21. Engelhardt, M. et al. Creatine supplementation in endurance sports Med. Sci. Sports Exerc., 1998; 30:7, 1123 1129.
22. Peyrebrune, M.C. et al. The effects of oral creatine supplementation on performance in single and repeated sprint swimming. J. Sports Sci., 1998; 16:3, 271 279.
23. Jones, A.M. et al. Oral creatine supplementation improves multiple sprint performance in elite ice-hockey players. J. Sports Med. Phys. Fitness., 1999; 39:3, 189 196.
24. Mujika, I. et al. Creatine supplementation and sprint performance in soccer players. Med. Sci. Sports Exerc., 2000; 32:2, 518 525.
25. Maganaris, C.N. & Maughan, R.J. Creatine supplementation enhances maximum voluntary isometric force and endurance capacity in resistance trained men. Acta. Physiol. Scand., 1998; 163, 3: 279 287.
26. McNaughton, L.R. et al. The effects of creatine supplementation on high-intensity exercise performance in elite performers. Eur. J. Appl. Physiol., 1998; 78:3, 236 240.
27. Prevost, M.C. et al. Creatine Supplementation Enhances Intermittent Work Performance. Research Quarterly for Exercise and Sport., 1997; 68, 3: 233 - 240.
28. Kraemer, W.J. & Volek, J.S. Creatine supplementation. Its role in human performance. Clin. Sports Med., 1999; 18:3, 651 - 666, ix.
29. Keast, D. et al. Depression of plasma glutamine concentration after exercise stress and its possible influence on the immune system. Med. J. Aust., 1995; 162: 15 - 18.
30. Wilmore, D.W. & Shabert, J.K. The role of glutamine in immunologic responses. Nutrition, 1998; 14: 618 626.
31. Yoo, S.S. et al. Glutamine supplementation maintains intramuscular glutamine concentrations and normalises lymphocyte function in infected early weaned pigs. J. Nutr., 1997; 127: 2253.
32. Yaqoob, P. & Calder, P.C. Glutamine requirement of proliferating T lymphocytes. Nutrition, 1997; 13: 646 - 651.
33. Scheppach, W. et al. Effect of free glutamine and alanyl-glutamine dipeptide on mucosal proliferation of the human ileum and colon. Gastroent., 1994; 107: 429 434.
34. McLennan, P.A. et al. Inhibition of protein breakdown by glutamine in perfused skeletal muscle. FEBS, 1988; Lett. 237: 133 136.
35. Coyle, E. Timing and method of increased carbohydrate intake to cope with heavy training, competition and recovery. J. Sports Sci., 1991; 9: 29 52.
36. Hawley, J.A. et al. Carbohydrate, fluid, and electrolyte requirements of the soccer player: a review. Int. J. Sport Nutr., 1994; 4:3, 221 236.
37. Kang, J. et al. Effect of carbohydrate ingestion subsequent to carbohydrate super compensation on endurance performance. Int. J. Sports Nutr., 1995; 5,4: 329 343.
38. McConnell, G. et al. Effect of timing carbohydrate ingestion on endurance exercise performance. Med. Sci. Sports Exerc., 1996; 28,10: 1300 - 1304.
39. Coombs, J.S. & Hamilton, K.L. The Effectiveness of Commercially Available Sport Drinks. Sports Med., 2000; 29,3: 181 209.
40. Johnson, H.L. et al. Effects of electrolyte and nutritional solutions on performance and metabolic balance. Med. Sci. Sports Exerc., 1988; 20,1: 26 33.
41. Millard-Stafford, M et al. Water versus carbohydrate-electrolyte ingestion before and during a 15-km run in the heat. Int. J. Sports Nutr., 1997; 7,1: 26 38.
42. Fallowfield, J.L. et al. The influence of ingesting a carbohydrate-electrolyte beverage during 4 hours of recovery on subsequent endurance capacity. Int. J. Sport Nutr., 1995; 5:4, 285 299.
43. Burke, L.M. & Read, R.S.D. Dietary Supplements in Sport. Sports Med., 1993; 15,1: 4365.
44. Maughan, R.J. Fluid and electrolyte loss and replacement in exercise. J. Sports Sci., 1991; 9, 117 142.
45. Maughan, R.J. & Noakes, T.D. Fluid replacement and exercise: a brief review of studies on fluid replacement and some guidelines for the athlete. Sports Med., 1991; 12: 16 31.
46. Maughan, R.J. & Leiper, J.B. Limitations to fluid replacement during exercise. Can. J. Appl. Physiol., 1999; 24, 2: 173 187.