Sports nutrition

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Sports nutrition is the study and practice of nutrition and diet as it relates to athletic performance. It is concerned with the type and quantity of fluid and food taken by an athlete, and deals with nutrients such as vitamins, minerals, supplements and organic substances such as carbohydrates, proteins and fats. Although an important part of many sports training regimens, it is most commonly considered in strength sports (such as weight lifting and bodybuilding) and endurance sports (for example cycling, running, swimming).

Supplements[edit]

All athletes consider taking dietary supplements because they are looking for the “magic ingredient” to increase performance.[1] In the extreme case of performance-enhancing supplements, athletes (particularly bodybuilders[citation needed]) may choose to use illegal substances such as anabolic steroids, compounds which are related to the hormone testosterone, which can quickly build mass and strength, but have many adverse effects such as high blood pressure and negative gender specific effects. Blood doping, another illegal ergogenic, was discovered in the 1940s when it was used by World War II pilots.[2]

Dietary protein began to be consumed in the 1940s and muscle building results were found in resistance and strength training athletes.[2] Protein intake is a part of the nutrient requirements for the regular athlete and is an important component of exercise training, because it can also aid in performance and recovery. Dietary protein intake for well-trained athletes should occur before, during and after physical activity as it is advantageous in gaining muscle mass and strength.[3] However, if too much protein and amino acid supplements are consumed (especially by the Average Joe exerciser), it can be more harmful than beneficial; health risks include: “dehydration, gout, calcium loss, liver, and renal damage [and] gastrointestinal side effects include diarrhea, bloating, and water loss" (Lawerence). A bountiful protein diet must be paired with a healthy, well-rounded meal plan and regular resistance exercise. Yet, characteristics such as the type of exercise, intensity, duration, the carbohydrate values of diet, the individual's sex and age and also the amount of background training and training environment.[4]

Creatine may be helpful for well-trained athletes to increase exercise performance and strength in concordance with their dietary regimen.[4] Also, the substance glutamine, found in whey protein supplements, is the most abundant free amino acid found in the human body.[5] For well-trained and well-nourished athletes it is considered that glutamine may have a possible role in stimulated anabolic processes such muscle glycogen and protein synthesis.[5] Other popular supplements studies done include androstenedione, chromium, and ephedra. The findings show that there are no substantial benefits from the extra intake of these supplements, yet higher health risks and costs.[4]

High energy supplements have shown to increase the performance of physical activity. A study done at the University of Texas saw a 4.7% increase of performance in 83% of participants after drinking Red Bull Energy Drink which was more intense than the compared placebo. The energy drink most dominantly increased the epinephrine and noreprinephrine (adrenaline and its precursor) levels and beta-endorphins in the blood than before consumption. Caffeine, carbohydrates and Vitamin B are factors that may have favored performance increase with no change in perceived exertion.[6]

Caffeine has been known since the 1900s and became popularly used since the 1970s when its power of masking fatigue became highly recognized.[2] Similarly, the caffeine found in energy drinks shows an increased reaction performance and increased good feelings of energy, focus and alterness in quickness and reaction anaerobic power tests. In other words, consuming an energy drink with caffeine increases short time/rapid exercise performance (like short full-speed sprints and heavy power weight lifting.)[7]

Post-exercise nutrition is just as important, if not more important than pre-exercise nutrition as it pertains to recovery. Traditionally, sports drinks such as Gatorade and Powerade, are consumed during and after exercise because they effectively rehydrate the body by refueling the body with minerals and electrolytes. Gatorade was founded in the 1960s, when the University of Florida, Gainesville Gators improved their performance with “Gator Aid.” A drink was made of glucose and sucrose in water and helped the football players' performance. And by the 1970s, many other sports drinks of its kind had been manufactured.[2] However, sports drinks lack protein.

New studies[citation needed] in 2008 have found milk, especially skim milk and chocolate milk may be the new sports drink [clarification needed], as milk leads to protein the synthesis which boosts net muscle protein balance. Milk naturally contains many electrolytes, nutrients and other properties that help to make it a great post-exercise beverage.

When compared to plain water or sports drinks, research suggests that chocolate milk is more effective at replacing fluids lost as sweat and maintaining normal body fluid levels. Athletes drinking chocolate milk following exercise-induced dehydration had fluid levels about 2 percent higher (on initial body mass) than those using other post-exercise recovery beverages, allowing for prolonged performance, especially in repeated bouts of exercise or training.[8]

Factors influencing nutritional requirements[edit]

Differing conditions and objectives suggest the need for athletes to ensure that their sports nutritional approach is appropriate for their situation. Factors that may affect an athlete's nutritional needs include type of activity (aerobic vs. anaerobic), gender, weight, height, body mass index, workout or activity stage (pre-workout, intra-workout, recovery), and time of day (e.g. some nutrients are utilized by the body more effectively during sleep than while awake). Most culprits that get in the way of performance are fatigue, injury and soreness. A proper diet will reduce these disturbances in performance. The key is to get a variety of food, to get all the macronutrients, vitamins, and minerals. According to Eblere's article (2008), it is optimal to choose raw, unprocessed foods such as oranges instead of orange juice. Eating foods that are natural means the athlete is getting the most nutritional value out of the food. When foods are processed it normally means that nutritional value is reduced.[9]

Anaerobic exercise[edit]

During anaerobic exercise, the process of glycolysis breaks down the sugars from carbohydrates for energy without the use of oxygen. This type of exercise occurs in physical activity such as power sprints, strength resistances and quick explosive movement where the muscles are being used for power and speed, with short-time energy use. After this type of exercise, there is a need to refill glycogen storage sites in the body (the long simple sugar chains in the body that store energy), although they are not likely fully depleted.

To compensate for this glycogen reduction, athletes will often take in a large amount of carbohydrates in the period immediately following exercise. Typically, high-glycemic-index carbohydrates are preferred for their ability to rapidly raise blood glucose levels. For the purpose of protein synthesis, protein or individual amino acids are ingested as well. Branched-chain amino acids are important since they are most responsible for protein synthesis. According to Lemon et al. (1995) female endurance runners have the hardest time getting enough protein in their diet. Endurance athletes in general need more protein in their diet than the sedentary person. Research has shown that endurance athletes are recommended to have 1.2 to 1.4 g of protein per kg of body weight in order to repair damaged tissue. If the athlete consumes too few calories for the body's needs, lean tissue will be broken down for energy and repair. Protein deficiency can cause many problems such as early and extreme fatigue, particularly long recovery, and poor wound healing. Complete proteins such as meat, eggs, and soy provide the athlete with all essential amino acids for synthesising new tissues. However, vegetarian and vegan athletes frequently combine legumes with a whole grain to provide the body with a complete protein across the day's food intake.[10] A popular example is rice and beans.[11]

The following information on the types of carbohydrates comes from Spada’s research on endurance sports nutrition (2000). He advises carbohydrates to be unprocessed and/or whole grains for optimal performance while training. This is because these carbohydrates offer the most fuel, nutritional value, and satiety. Fruits and vegetables contribute important carbohydrate foundation for an athlete's diet. They both provide vitamins and minerals that are lost through exercise and need to be replenished. Both fruits and vegetables improve healing, aid in recovery, and reduce risks of cancer, high blood pressure, and constipation. Vegetables offer a little more nutritional value than fruits for the amount of calories, therefore an athlete should strive to eat more vegetables than fruits. It is also important to look at the certain types of vegetables and fruits. Dark-colored vegetables usually have more nutritional value than pale colored ones. A general rule is the darker the color the more nutrient dense it is. Like all foods, it is very important to have a variety. To get the most nutritional value out of fruits and vegetables it is important to eat them in their natural, unprocessed form with no other nutrient (sugar) added.[12]

Often in the continuation of this anaerobic exercise, the product from this metabolic mechanism builds up in what is called lactic acid fermentation. Lactate is produced more quickly than it is being removed and it serves to regenerate NAD+ to the cells where it's needed. During intense exercise when oxygen is not being used, a high amount of ATP is produced and pH levels fall causing acidosis or more specifically lactic acidosis. Lactic acid build up can be treated by staying well-hydrated throughout and especially after the workout, having good cool down routine and good post-workout stretching.[13]

Intense activity can cause significant damage to bodily tissues. In order to repair, vitamin E and other antioxidants are needed to protect muscle damage. Oxidative damage and muscle tissue breakdown happens all the time in endurance running so athletes need to eat foods high in protein in order to repair these muscle tissues. It is important for female endurance runners to consume proper nutrients in their diet that will repair, fuel, and minimize fatigue and injury. To keep a female runner’s body performing at its best, ten nutrients need to be essential in diets.[14]

See also[edit]

References[edit]

  1. ^ Maughan, Ronald J., ed. "Sports Nutrition: What Is It?" Journal of Nutrition & Physical Activity 17 (2001). 2001. Elsevier Science Inc. 25 Mar. 2009.
  2. ^ a b c d Applegate, Elizabeth A., and Louis E. Grivetti. "Search for the Competitive Edge: A History of Dietary Fads and Supplements." The Journal of Nutrition (1997): 869S-73S. The Journal of Nutrition. American Society for Nutritional Sciences. 1 Apr. 2009 <jn.nutrition.org>.
  3. ^ Campbell, Bill, Richard B. Kreider, Tim Ziegenfuss, Paul La Bounty, Mike Roberts, Darren Burke, Jamie Landis, Hector Lopez, and Jose Antonio. "International Society of Sports Nutrition position stand: protein and exercise." Journal of the International Society of Sports Nutrition 4 (2007). Journal of the International Society of Sports Nutrition. 26 Sept. 2007. BioMed Central Ltd. 25 Mar. 2009 <http://www.jissn.com/content/4/1/8>.
  4. ^ a b c Lawrence, Marvin E., and Donald F. Kirby. "Nutrition and Sports Supplements Fact or Fiction." Journal of Clinical Gastroenterology 35 (2002): 299-306. Journal of Clinical Gastroenterology. 2002. Lippincott Williams & Wilkins. 25 Mar. 2009 <journals.lww.com/jcge/>.
  5. ^ a b Gleeson, Michael. "Dosing and Efficacy of Glutamine Supplementation." The Journal of Nutrition (2008): 2045S-049S. Nov. 2008. 25 Mar. 2009 <jn.nutrition.org>.
  6. ^ Ivy, John L., Zhenping Ding, Bei Wang, Jeffery R. Bernard, Yi-Hung Liao, and Jungyun Hwang. "Improved Cycling Time-Trial Performance After Ingestion of a Caffeine Energy Drink." International Journal of Sport Nutrition and Exercise Metabolism 19 (February 2009): 61-78.
  7. ^ Hoffman, Jay R., Jie Kang, Nicholas A. Ratamess, Mattan W. Hoffman, Christopher P. Tranchina, and Avery D. Faigenbaum. "Examination of a pre-exercise, high energy supplement on exercise performance." Journal of the International Society of Sports Nutrition 6 (2009). Journal of the International Society of Sports Nutrition. 6 Jan. 2009. BioMed Central Ltd. 25 Mar. 2009
  8. ^ Stager, Joel M., et al. "Chocolate Milk as a Post-Exercise Recovery Aid." International Journal of Sport Nutrition and Exercise Metabolism. 2006. <http://www.winforum.org/chocolatemilkrecovery.html>.
  9. ^ Eberle, S. G. "Endurance sports nutrition". Fitness Magazine 24 (6): 25. 
  10. ^ Jurek, Scott (2012). Eat and Run. London: Bloomsbury. 
  11. ^ Lemon P. "Do athletes need more dietary protein and amino acids?". International journal of sports nutrition 5: 39–61. 
  12. ^ Spada R. "Endurance sports nutrition". Journal of Sports Medicine & physical Fitness 40 (4): 381–382. 
  13. ^ Delamere, Nicholas, and Claudia Stanescu. "Muscle Energetics." Physiology 201. University of Arizona, Tucson. 25, 27, 29 Mar. 2009.
  14. ^ Rokitzki L. "Alpha-tocopherol supplementation in racing cyclist during extreme endurance training". International Journal of sports nutrition 4 (3): 253–64. 

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