A look at sports nutrition supplements

Sports Nutrition Branda Busby Concordia College, Moorhead, MN Objectives  Identify how optimal nutrition and proper hydration can enhance athletic performance  Identify the benefits and dangers of supplements and ergogenic aids  Understand sports related eating disorders and appropriate ways to counsel athletes who want to lose weight Importance of Sports Nutrition  What an athlete eats and drinks can affect health, weight & body composition.  Optimal nutrition will fuel the body during exercise, reduce recovery time, and improve performance Significance of Adequate Nutrition before Exercise  The preexercise meal has been shown to improve performance  Meal should be high in fluids, low in fat and fiber, high in carbohydrate, moderate in protein, and familiar to the athlete. Importance of Carbohydrates  Maintain bloodglucose levels during exercise  Replace muscle glycogen  Recommendations range from 6 to 10 g/kg body weight per day Carbohydrate Loading  Carbohydrate loading in the pre-event meal is designed to maximize the storage of glycogen in muscle & liver tissues  An athlete should consume 200 to 300 grams of carbohydrate within 3 to 4 hours before exercise.  Recommendations of carbohydrate consumption within 1 hour of competition is controversial due to research studies that say this leads to hypoglycemia and premature fatigue. Examples of Preexercise Snacks         Bananas Carrots Cereal Dried fruit Granola bars Wheat thins Oatmeal Bagels Functions of a Precompetition Meal  Allow for the stomach to be relatively empty at the start of competition  Help prevent or minimize gastrointestinal distress  Help avoid hunger sensations & fatigue  Provide adequate fuel to the body  Provide an adequate amount of water in order to prevent dehydration Liquid Meals  Advantages – well balanced, high amount of carbohydrates, no bulk (fiber), are easily digested, and are convenient & economical.  Examples – Nutrament, GatorPro, Ensure, Slim-Fast. Each provide about 250-400 kcals  Should be taken closer to competition than a solid meal (2 to 3 hours before) Sports Bars  Sports bars are a good source of carbohydrate and contain some fat.  They are convenient and can be used as preevent meals, but DO NOT possess qualities that enhance physical performance  Liquid meals and sports bars should be used as a substitute for a precompetition meal, but should not be used long term to replace your normal diet Nutrition during Competition  Replace fluid losses and provide 30 to 60 grams of carbohydrate per hour.  These guidelines are especially important for endurance events, and when exercising in extreme conditions. Hydration  Exercise performance is optimal when fluid balance is maintained  Performance is impaired with progressive dehydration  Dehydration increase the risk of heat stroke which can be life-threatening Important Terms  Dehydration – consequence of fluid losses that exceed fluid intake  Hypohydration- when athletes dehydrate themselves prior to competition via diuretics or sauna  Hyponatremia- low blood sodium which occurs after prolonged sweating with failure to replace sodium or it occurs when excess water is retained in the body. Fluid Recommendations  Drink generous amounts of fluid in the 24 hours before event  Drink 400-600 ml 2 to 3 hours before event  Drink 150 to 350 ml every 15 to 20 minutes during exercise Sports Drinks  Sports drinks containing 4 to 8% carbohydrate are beneficial to events lasts longer than one hour.  Examples- Excel, GatorAde & PowerAde  Sodium amounts between .5 & .7 g/L is also recommended to improve palatability which increases the drive to drink and to prevent hyponatremia. Function of Postexercise Meal  Prevents hunger  Maximized glycogen stores  Prevents physical and mental fatigue  The postexercise meal is critical for athletes practicing daily and especially for those exercising twice a day. Post-Competition Meal Recommendations  One should eat 1.5 grams carbohydrate per kg body weight & small amount of protein within 30 minutes after exercise  Protein may help muscles recover faster Glycemic Index of Foods  Foods with a high glycemic index (starchy foods) replenish muscle glycogen faster than those with a low glycemic index (foods high in fiber)  Examples of foods with high glycemic index include bagels, corn flakes, raisins, bread and candy  Example of foods with low glycemic index are apples, peaches, milk, beans and yogurt. Macronutrient Requirements  Carbohydrate – maintains glucose levels in the blood and replenishes muscle glycogen  Protein- Repair muscle damage and supports gains in lean muscle mass  Fat – powerful mediators of the immune system and may decrease the immunosuppressive effects of exercise Micronutrient Requirements  Calcium & Vitamin D improve bone health and reduce the risk of stress fractures.  Iron is required for formation of hemoglobin & myoglobin which bind oxygen  Antioxidants (Vitamins A, C, & E) protect the cell membranes from oxidative damage  B-Complex Vitamins are involved in energy production, RBC production, protein synthesis & tissue repair When is Vitamin Supplementation Necessary  When athletes use severe weight loss programs especially when their caloric intake is between 1200- 1600 calories per day  When whole food groups are eliminated such as a vegetarian who eliminates meat may be deficient in Iron and Zinc  When athletes consume high carbohydrate, low nutrient-dense foods Supplements & Ergogenic Aids  Ergogenic Aids- items claiming to increase work output or performance  The marketing of ergogenic aids is a multimillion dollar business that preys on the desires of athletes to be the best.  The Dietary Supplement Health and Education Act of 1994 allows manufacturer to claim for enhanced physical performance whether valid or not as long as they don’t claim to “diagnose, mitigate, treat, cure or prevent” a specific disease Effectiveness of Ergogenic Aids  Those that perform as claimed  Those that may perform as claimed but there is no evidence at this time  Those which are dangerous and illegal and shouldn’t be used Classification of Ergogenic Aids  Metabolic fuels (carbohydrate, lactate, fat)  Cellular components that improve metabolism (creatine, carnitine, vitamins)  Anabolic substances that enhance performance (protein, AAs, chromium, plant sterols, herbals)  Substances that enhance recover (fluids, electrolytes) Guidelines for Supplement Use  Evaluate your current diet and try to fill gaps with food  Give supplements a few weeks before deciding if it works  Stop taking any supplement that causes ill side effects  If you find a supplement that works take time off every few weeks  Remember a balanced diet is the best sports nutrition and no supplement can make up for poor eating Types of Supplements Type of supplement Possible Side Effects High BP, racing hear, stroke, seizure, death Change in cholesterol levels & increase in female hormone estrogen Muscle cramping, kidney problems Ephedra- herbal stimulant which is the MOST hazardous Androstenedione Creatine- research has proven some success Creatine  Most dietary creatine is derived from meat, but it would be impossible to eat enough to influence athletic performance  Creatine works by maintaining levels of ATP  A creatine supplement is most advantageous in short-term, high-intensity sports such as football or power lifting rather than endurance sports Hyperhydrating with Glycerol  Glycerol has osmotic properties which help in fluid retention.  Glycerate & ProHydrator are example of this new sports supplement  Suggested dosage is 1g/kg body weight to be taken with 1.5 L of fluid within 1 to 2 hours prior to competition Advantages & Disadvantages of Glycerol Supplementation  Advantages   Disadvantages    Reduced risk of dehydration and thermal injuries Reduced urine output during activity Improved thermoregulation especially for endurance athletes  Increased risk of cerebral and intraocular dehydration There is minimal research of the effects of taking large volumes of glycerol over a long period of time Research Study on Glycerol Effects  4 men & 2 women performed 90 minutes of treadmill exercise at 60% oxygen consumption in a dry, hot environment  Exercise was administered 2.5 hours after glycerol was ingested  80% of fluid intake was retained in subjects who took glycerol and only 50% was retained in subject who(1999). drank water Wagner, Dale R. only Hyperhydrating with glycerol: implications for athletic performance. Journal of the American Dietetic Association 99: 207-213 Evaluate Scientific Validity of an Ergogenic Aid  Was the research sponsored by the manufacturer?  Does the claim make sense for the sport for which the claim is made?  Are appropriate amounts of the ergogenic substance used?  What is the evidence that it works? (testimonial or scientific study) Safety and Legal issues of the Ergogenic aid  Is the product safe?  Does it contain toxic or unknown substances?  Does the product claim to replace food or good training practices?  Is the product illegal or banned by athletic organizations? Sports related eating problems  The loss of excess weight may improve performance in some sports  Examples of sports that stress weight loss are wrestling, gymnastics, ballet, figure skating & distance running. Signs of Anorexia Athletica  Immense fear of gaining weight  Severe caloric restriction  Weight loss  Gastrointestinal complaints  No medical explanation for thinness *Athletes must meet all 5 in order to be diagnosed with anorexia athletic plus the must meet 1 or more of the following -Disturbed body image, binge eating, purging methods, delayed puberty, menstrual dysfunction The Female Triad  Disordered Eating – athletes who have some characteristics of an eating disorder  Amenorrhea – loss of menstrual function for 3 to 6 months  Osteoporosis- loss of bone mass which may lead to stress fractures Signs of Anorexia Nervosa & Bulimia Nervosa  Anorexia Nervosa    Bulimia Nervosa      Dramatic weight loss Preoccupation with food, calories & weight Wears baggy clothing Mood swings Avoiding food- related social activities    Noticeable weight loss Excessive concern about weight Visits bathroom after meals Depressed Strict dieting followed by eating binges Can Excessive Weight loss Impair Physical Performance?  “Weight Cutting”- food restriction, fluid deprivation, and dehydration affects health, growth, development and can have a negative affect on physical performance  Short term starvation lowers blood glucose and muscle glycogen decreases performance  Long term starvation leads to losses in lean muscle mass which decreases performance Weight Management Strategies for Athletes  Set realistic goals    At what weight do you perform best? What is the maximum weight you would find acceptable? What was the last weight you maintained without without constantly dieting?  Encourage less focus on the scale  Monitor changes in energy level & exercise performance  Help athletes maintain a healthy weight for themselves not for their sport!!!!! Weight Loss Suggestions  Whole grains and cereals, beans, and legumes  5 or mores servings of fruits and vegetables  Don’t skimp on protein  Chose a variety of fluids  Eat Breakfast  Don’t skip meals  Don’t categorize foods as “good” or “bad” Ethical Issues in Sports Nutrition  The use of supplements and ergogenic aids in enhancing athletic performance. Is it cheating? Is it safe?  Emphasis on weight loss to increase physical performance. Should coaches be allowed to encourage weight loss? Our Role as Dietitians  Discourage unrealistic weight & body composition goals  Emphasize adequate energy for health, injury prevention, and exercise performance  Assess appropriate weight and composition for specific sports and individuals  Assess athlete’s dietary and supplement intake during competition & off season  Assess fluid intake and weight loss of athletes during exercise  Evaluate vitamin supplements and ergogenic aids that any athlete wants to use  Give appropriate recommendations Sports Nutrition Reference List Burke, Edmund R. (2000). Better Nutrition’s 2000 Sports Supplement Guide. Better Nutrition 62: 52-65. Dolby, Victoria. (1998). The building blocks of sports performance. Better Nutrition 60:38. Manore, Melinda M., Barr, Susan I., Butterfield, Gail E. (2000). Position of the American Dietetic Association, Dietitians of Canada, and the American College of Sports Medicine: Nutrition and athletic performance. Journal of the American Dietetic Association 100: 15431570. Shattuck, Deborah. (2001). Sports nutritionists fuel the competitive edge. Journal of the American Dietetic Association 101:517-521.  References Cont. Venkatraman, J.T., Leddy, J., Pendergast, D. (2000). Medicine & Science in Sports & Exercise. Journal of the American Dietetic Association 101: 263. Wagner, Dale R. (1999). Hyperhydrating with glycerol: implications for athletic performance. Journal of the American Dietetic Association 99: 207-213. Walsh, Julie. (1997). Powerful pills or pricey placebos? A look at sports nutrition supplements. Environmental Nutrition 20: 1-2. Williams, Melvin H. Nutrition for Health, Fitness & Sport, 5th edition. McGraw-Hill Companies, Inc, Boston: 1999.