150 likes | 326 Vues
Nutritional Aids. By Nora, Leah, Justin & Taylor. Introduction. Many athletes use dietary supplements as part of their regular training or competition routine, including about 85% of elite track and field athletes.
E N D
Nutritional Aids By Nora, Leah, Justin & Taylor
Introduction • Many athletes use dietary supplements as part of their regular training or competition routine, including about 85% of elite track and field athletes. • Supplements include vitamins, minerals, protein, amino acids, creatine, carnitine and caffeine. • Often used without a full understanding of the potential benefits and risks associated with their use. • Are they necessary for athletes? What are the risks?
Vitamins & Minerals • Many athletes take nutritional supplements in doses up to 1000 times the Dietary Reference Intakes. • In general, vitamin and mineral supplements have not been proven to improve training or performance. • Negative Side-effects: • Illness • Tissue damage • Vitamins can be toxic when taken in excess
Over 90% of vitamin supplements on sale are synthetic. • Nutritionists recommend food first because it provides a wide variety of vitamins and minerals and other dietary factors that are not found in supplements. • The body is better at breaking down these natural foods than synthetic supplements. • Supplements can be beneficial only when the athlete has a clear deficiency • Pregnant women • Adults over 50 • Vegetarians
Protein and Amino Acid Supplements • Protein and amino acids are an essential component of any balanced diet • Supplements used to increase muscle mass, strength and endurance • Some studies show that amino acids enhance the growth hormone insulin • Too much protein can cause your body to have toxic effects due to too much urea, which leads to loss of water • This dehydration can cause cramps and decrease your abilities in sport.
Are Amino Acid Supplements Effective? • http://www.youtube.com/watch?v=fciZtBMek7o
Creatine • Used for short-term, high-intensity exercise. • Found in skeletal muscle and is where the rapid production of ATP takes place, which provides immediate energy. • When phosphocreatine stores are depleted, creatine supplements are taken to refill and increase the content in skeletal muscle. • Consuming carbohydrates can increase the uptake of creatine by more than 50%.
Creatine does not improve the bodies maximum force, it allows the body to maintain a high-intensity exercise longer. • There is a limit that can be reached and the excess is excreted from the body. • Improvement is only obvious during sprint exercises during running, swimming, and cycling.
Carnitine • Synthesized in the kidneys and liver and stored in skeletal and cardiac muscles. • Found in living cells that is used to transport fatty acids to the mitochondria during the breakdown of lipids for the generation of metabolic energy.
Carnitine Cont’d • Theorized to be a super fat burning substance but that has never been proven • Carnitine supposedly decreases lactate production, delays fatigue, increases VO2, spares glycogen, and induces the loss of body fat. • Carnitine deficiency is not a concern for athletes as adequate levels remain in muscle tissues during exercise.
Carnitine’s importance • Carnitine is important for the muscle because it: • Improves the efficiency or production of ATP with oxygen • Reduces the need for anaerobic glycolysis • Can result in a 44% reduction of Lactate production.
Caffeine Pros Cons Potential diuretic effect which could cause dehydration, nervousness and irritability Can enable athletes to go beyond safe physiological limits by delaying fatigue Risk of drug dependency • Can increase performance during prolonged endurance and short-term intense exercise • Increases alertness and reduces fatigue Urinary caffeine limit: more than 3 cups of coffee before a competition
Do Athletes Need Supplements? • http://www.youtube.com/watch?v=b1rkmr2Jn_0
References • http://www.dietitians.ca/Nutrition-Resources-A-Z/Factsheets/Supplements/Do-I-Need-a-Supplement-.aspx • http://www.heart.org/HEARTORG/Conditions/Vitamin-Supplements-Healthy-or-Hoax_UCM_432104_Article.jsp# • http://www.netdoctor.co.uk/dietandnutrition/feature/vitamins.htm • http://www.ncbi.nlm.nih.gov/pubmed/18049988 • http://www.theraceclub.net/nutrition/l-carnitine-shown-to-improve-athletic-performances/