Nutritional Evaluation of a Young Athlete - Essay Example

Nutritional Evaluation of a Young Athlete Part A Background: For physically active individuals, a steady supply of nutritional elements and supplementation represents insurance that deficiencies of nutrients would not occur, thus would not affect the performance adversely. In fact, it has been appropriately stated that making sound nutritional choices does not guarantee athletic prowess, but poor nutritional choices almost certainly constraints performance always. Specifically stated, sound nutrition is necessary always to effectively train and take advantage of training stimuli. In the practice of sports nutrition, the concepts of nutritional research are combined with exercise physiology. This attempts to optimize health and athletic performance through sound dietary intervention. It is clear from the recent literature that total energy and macronutrient composition of the diet modulates acute exercise performance and adaptation to training. Since athletic activities demand high amount of energy, it is important to understand how energy is produced and how the demand for energy during athletics drives energy utilization. This understanding can be utilized and is critical to recommend appropriate dietary choices to replace that energy and refuel for the next bout of athletic activity (Bowman, B.A. and Russell, R.M., Eds., 2002). Principles: The basic principles of energy transduction dictate that the flow of energy into the body must balance energy flow out of the body plus or minus energy storage. The human species is adapted to survive in the face of intermittent food availability; therefore, the efficient storage of food energy in periods of abundance is a metabolic priority. The form of energy that is utilized for performance of activity is adenosine triphosphate (ATP). ATP storage in the body is severely limited, therefore, there must be storage form of energy that can be rapidly activated and can respond to changes in energy demand at the time of athletic activity. Phosphocreatine serves as the most rapidly accessible form of energy storage. The enzyme creatine kinase catalyzes a reaction that results in transfer of phosphate group from Phosphocreatine (PCr) to adenosine diphosphate to form ATP. During rapid high-intensity exercise, PCr stores are depleted in a few seconds and therefore needs to be replenished during the recovery period (Bender, D.A., 2003). Objective of Nutritional Assessment: The basic concept in athletic nutrition is balance between energy expenditure and nutritional intake. From the above principles, it is clear that endurance athletes need protein, carbohydrates, and fluid in greater amounts. It also enumerates that the nutritional needs of the athletes must be sport-specific and individualized. While the concept of achieving energy balance is simple apparently from the thermodynamic perspective, the tools for measuring this entity are no ideal. This is specifically applicable to the estimation of energy intake that unless observed and quantified is usually left to the subjective recall of the athletes who are entrusted to remember, accurately estimate, and document their food intake using some record of diet. Even though, the athletes practice the most conscientious record, there are several limitations in such methods. To name a few, these are dietary constituent of interest; monitoring techniques, such as, 24-hour recall, food frequencies, and diet record; seasonal changes in training and eating; and natural limitations imposed by estimation techniques and subject compliance. Measurement of food intake may alter the dietary practice. Energy expenditure measurement can be very accurate when measured in a controlled laboratory by indirect calorimetry. Thus definitive assessment of energy balance and control can only reliably be afforded by measurement of fluctuations in body weight and body composition (National Research Council, 1989). Anthropometry: The relationships between diet, athletic activity, and weight are closely linked. Ordinary factors, such as, training, acclimatization, mismatch between exercise fluid loss and fluid intake, intentional dehydration for weight control can each uniquely affect body water content. Body composition assessment by anthropometric measurements and analysis of diet by software can thus be practically applicable in being able to assess the appropriate nutrition for an athlete (Buzina, R., Grgic′, Z., Jusic, M., Sapunar, J., Milanovic, N. and Brubacher, G., 1982) Part B: Data Acquisition and Presentation The Profile: The athlete in question is a 25-year-old young male with acceptably normal health. He is immunized with no history of hospitalization or surgery in the recent or remote past. He does not have any acute or chronic injuries. There is no significant prescription history, the last medical was perfectly within normal limits. He uses regular recommended vitamin and mineral supplements. He does not use any laxatives or topical medications or any herbal remedies. He does not smoke, drink, or use any illicit drugs. Family history is insignificant. He does not have any allergy to any food or medications. He does not take any caffeinated beverages. He follows a tight, rigorous, and disciplined training schedule, and he pursues a competitive athletic career of a mid-range sprinter. He is following a diet schedule provided by his trainer. Overall, his lifestyle can be termed healthy. He trains 4 hours a day and takes adequate amount of fluid before and after the training. At present, he is participating in state-level competitions and is determined to win. Data Record: Body composition is a composite of skeletal mass, adipose tissue, and muscle protein. Body fat and muscle mass can be calculated anthropometrically. Determination of body composition is an important element in describing the nutritional health of an athlete. Nutritional anthropometry capitalizes on the connection between the nutritional history of an individual and his body morphology, that is, size, shape, and composition. Disparities between energy nutrient intake and energy nutrient requirements are registered in the morphology of the body. The greater the disparity between the intake and output, the greater would be the morphological alteration from wasting to obesity. The anthropometric measures that were used in this athlete were weight, height, skinfold thickness, and midarm muscle area (Clarkson, P.M., 1998). Body weight is the most commonly measured anthropometric parameter. This is considered to include body fat plus fat-free mass that comprises of water, protein, glycogen, and minerals. The state of body hydration can have profound effects on body weight with dehydration being associated with lower body weights. Body weight does not reflect body composition accurately. In order the weight to be meaningful, weight and height must be considered together. Skin fold measurements were utilized to measure body fat. The validity of this technique of anthropometric assessment is predicted on several as yet unproven assumptions (Astrand, P.O. and Rodahl, K., 1986). One such assumption is that subcutaneous adipose tissue makes up 50% of total body fat. Body fatness was estimated from the skin folds by means of prediction equation. Body weight was measured using beam balance before eating and after voiding. The volunteer was wearing light clothing without shoes. The body weights recorded was 150 pounds. The height was measured with a calibrated stick attached to the wall, and the subject was in position of attention with the back in apposition to the wall. The height recorded was 6 feet 1 inch. The triceps fat fold was measured at the midpoint of the arm between acromion and the olecranon processes. A fold of skin with subcutaneous fat was grasped, and this was gently pulled away from the skin. The caliper was placed over the fat fold, and the measurements were read at the nearest 1.0 mm. Three readings were taken, and the average was recorded as the reading. This volunteer had an average record of 2.4 mm. Dietary Record: The athlete was asked to keep a dietary record regularly. He was required to mark the dates including a day prior, during, and after an event. He was instructed to record every minute details of food and fluid he consumed throughout these days including any dietary supplement. The subject is also advised to keep a diary of physical activities. The summary index was derived from the diary by summing the total duration of time spent in activity multiplied by an estimated rate of energy expenditure for that activity. Daily Energy Expenditure: The daily energy expenditure was calculated by Harris Benedict Equation. This uses BMR and then applies an activity factor to determine total calorie expenditure. The BMR formula that states BMR = 66 + (6.23 x weight in pounds ) + ( 12.7 x height in inches ) - ( 6.8 x age in year ) applied to our subject gives a BMR of 1756.6. The total daily calorie needs for our subject will be hard exercise/sports 6-7 days a week applying formula BMR x 1.725. This gives a value of 3030 kcal (Fisher, A.G. and Jensen, C.R., 1991). Analysis of Dietary Data: The dietary dairy gave the following data. The subject was requested to record his fluid intake during the day for three days Breakfast Pre Training/Event Training Lunch Snacks Dinner Cereals 2 servings x d Energy drink 1 Water ½ cup every 15 mins Cereals 1 serving Fruits 2 Cereals 2 servings Vegetables 1 serving Water 2 cups Vegetables 1 serving Meat -1 ounce Fruit Juice 2 Meat1 ounce Vegetables 1 Water 2 cups Water 2 cups Water 2 cups With NATS version 2 analysis the component content of the diet is as below Part C: Critical Evaluation of Data Nutritional assessment of athletes provides a unique set of challenges for the nutritionist. The foremost priority in the nutritional care of the young athletes is maintenance of energy balance. If one puts these guidelines into practice, this translates into an eating strategy that adequately helps to meet the goals of increased energy demand as well as those of the recommended dietary allowances and dietary reference intakes. The following scientific principles are utilized for nutritional assessment. The duration, frequency, and intensity of the athletic activity determine the amount of energy expended during the activity, and the type of the activity performed determines the predominant energy pathways to be used in an athlete. Three energy pathways are utilized during high-intensity events lasting no longer than 4 seconds. As discussed earlier, ATP and creatine phosphate within the muscles provide the readily available energy for activity. This is known as the power pathway. The speed pathway is used for events lasting from 4 to 60 s. The major substrates used are glucose and muscle glycogen, and these are rapidly metabolized anaerobically through the glycolytic cascade. Typical events of this category include track events of less than 400 m or swimming events of less than 100 m. Approximately 25% to 30% of muscle glycogen stores are used during a single 30-s sprint or resistance exercise bout. Furthermore, if an individual is participating in repeated sprints, muscle glycogen is depleted with each sprint (McArdle, W.D., Katch, F.I., and Katch, V.L., 1996). Since neither power nor the speed pathways can provide sufficient energy for the muscles to contract at a very high rate for events lasting longer than about 2 mins. For these purposes, the endurance pathway is used. The major substrates for this pathway include glycogen from the muscle and liver, fat from muscle, blood, and adipose tissue as well as amino acids from the muscle, blood, and liver. As oxygen becomes more available to the working muscle, the body begins to switch from anaerobic systems to more aerobic ones. Only the aerobic endurance pathway can produce large amounts of ATP over extended periods of time via the Krebs cycle and the electron transport system. The changeover from anaerobic to aerobic pathways is not abrupt, and the intensity, duration, frequency of activity, type of activity, nutritional reserve, nutritional status, and fitness of the athlete determines when the crossover from primarily anaerobic to aerobic pathways occur. After 2 hours of activity, most of the energy is derived from the endurance pathway and only a trace from the anaerobic system. The more energy used in activity, the more calories need to be consumed in the diet. The energy expenditure must balance energy intake. Individuals training for an athletic event will require more kilocalories than a sedentary individual. The reference sedentary man weighs 154 pounds and expends 2700 to 3500 kcals a day between the ages 20 to 29 years; the same for the women this young age group would be 1890 to 2000 kcal. The cost of the iron man triathlon is approximately 4800 kcals, and the cost of training alone ranges from 3000 to 6000 kcals a day for a male athlete (Bell, G.H., Emslie-Smith, D., and Paterson, C.R., 1976). Seeing it from another aspect, approximately 50% to 60% of energy during 1 to 4 hour of continuous exercise at 70% of the maximal oxygen capacity is derived from carbohydrates, and the remaining energy is derived from the fat. As the intensity of the exercise decreases, a greater proportion of energy comes from the oxidation of free fatty acids. As the intensity of the exercise decreases, a greater proportion of energy comes from the oxidation of free fatty acids. Training does not alter the total amount of energy expended but rather changes the proportion of energy expended from the carbohydrates and fat. As a result of training, the energy derived from fat increases, and the energy derived from carbohydrate decreases. For mid- to moderate-intensity athletics, long-chain fatty acids derived from stored muscle triglycerides are the preferred fuels (Schoeller, D.A., 1988). Dietary Guidelines: These are predicated on consumption of adequate calories to sustain daily energy expenditure and should be provided on an individual basis. Since the subject of this study is a young male with need for professional athletic training activity, his energy expenditure would be 58 kcal/kg/day. The average endurance athlete should consume approximately 55 kcal/kg body weight. The energy needs range from 33 to 60 kcal/kg/day. Carbohydrates should be between 60 to 70% of the total kilocalories or 8 to 10 g/kg body weight. This is recommended specially for those who participate in training or events longer than an hour. Thus a 150-lb individual who requires 3750 kcal per day would ideally be having 1920 to 2700 kcal from carbohydrates, and this would require consumption of 280 to 675 g of carbohydrates per day. However, in times of lean seasons, this athlete training for less than 1 hour a day can re-synthesize glycogen adequately on dietary intakes of 6 g/kg body weight. Dietary fat intake should provide no more than 30% of the total kilocalories. Thus, the subject, a 150-lb athlete would need 125 g of fat. This athlete in training may decrease the intake to 20-25% of the total kilocalories to enable him to consume the larger quantities of carbohydrate required to prevent staleness. Adaptation to high-fat diet having greater than 60% kcals from fat will increase the contribution of fatty acid oxidation by 40% to total energy expenditure of exercise. It is to be noted that neither the rate of use of glycogen, nor an increased performance during moderate intensity exercise has been observed. The majority of the athletes consume adequate amounts of protein. However, protein requirements for athletes should be individualized to determine adequacy of intake. High-quality protein intake for the male endurance athlete performing at intensities above 65 to 85% of the VO2peak should be 1.0 to 1.6 g/kg body weight per day or 150 to 175% of the current recommended daily allowances for proteins. This is necessary to provide for the oxidation of the amino acids during high-intensity exercises. This 150-lb young man would, therefore, need about 75 to 113 g of protein per day. There is another aspect to be considered while recommending protein intake. Protein intake for the strength athletes must be provided to enhance muscle hypertrophy, but must also be individualized to the duration, frequency, and intensity of the activity. In early stages of the training, the estimated protein requirement is 1.5 to 1.7 g/kg body weight per day, but when the training enters the maintenance phase, the protein requirement decreases to 1.0 to 1.2 g/kg body weight per day preferably from animal sources. Protein intakes above 2.0 g/kg are oxidized for energy and do not enhance muscle mass or performance. Vitamin C has several important functions as related to athletic activity. This vitamin is necessary for collagen synthesis. Collagen is abundant in tissues is a vital component of cartilage, ligaments, tendons, or other connective tissue. Vitamin C is necessary for synthesis of carnitine that is necessary for transport of long-chain fatty acids into the mitochondria for extracting energy. Apart from utility in synthesizing neurotransmitters, this is needed for transport of nonheme iron, and it thus interfaces with physical activity at several levels. For a young athlete, the daily recommended dose is 1000 mg (MacDougall, J.D., Wenger, H.A., and Green, H.J., 1991). Water and Fluids: In any event lasting longer than 30 minutes, fluid and nutrient needs to take on greater importance and can influence performance. Water is the most important nutrient for regulating hydration status in the athlete. Water loss during athletic activity primarily occurs through sweat. Average losses during exercise can amount to 2 to 6% of a person’s body weight. Physical performance is impaired when 3 to 4% body weight is lost. Sweat rate, however, is influenced by ambient temperature, humidity, exercise intensity, and rate of exogenous fluid intake. Fluid intake prior to athletic activity is necessary to offset risk of dehydration during activity. Consumption of 400 to 600 mL fluid prior to competition is recommended. The practical recommendation is to consume 150 to 300 mL of water every 15 to 20 minutes of activity. When the activity lasts for more than 1 hour, addition of 4 to 8% carbohydrate and electrolytes can be beneficial. After athletic activity, fluid intake is recommended to replace losses. Body weight changes are the best methods determining the quantity of fluid replacements. For every 1 lb of weight loss, 500 mL fluid should be replaced (Howley, E.T. and Franks, B.D., 1997). Minerals: Athletically active individuals are required to consume calcium in amounts consistent with daily recommended intake for the age and sex. The young male athlete, our subject, would need to take 1000 mg/day with a maximal upper limit of 2500 mg/day. Athletes need to take higher amount of calcium because they lose a considerable amount of calcium while perspiring. However, to enhance absorption, the dose of calcium should not exceed 500 mg at any one time. Iron deficiency is a common nutrient deficiency, and it has been estimated that 30 to 50% of the athletes may be at risk of poor iron status. The reasons for iron loss in athletes may comprise loss in sweats, low consumption of iron-containing foods, and myoglobinuria from muscle stress during exercise. Iron is the single most important component of haemoglobin that is entrusted with the physiological responsibility of carrying oxygen to the tissues. Thus, iron deficiency as a result of decreased iron stores negatively impacts exercise performance as a result of decreased maximal oxygen consumption. Adequate iron intake ensures optimal performance. Analysis of the Present Diet and Recommendations: This data is indicating that our subject is in a state of negative energy balance and micronutrient deficits. His energy requirement is considerably less, and this will ultimately lead to calorie malnutrition. Micronutrients are also less than required in his diet. He needs calcium, vitamin, and iron supplementation. These would invariably cause energy deficits leading to loss of muscle mass, body fat depletion, and weight loss. Weight and energy have important contributions to performance, and eventually, the performance will be affected. The recommendations as per COMA Dietary Reference Values for this athlete would be 47.7% of the energy requirement as carbohydrates and 35.8% of fat. This athlete is consuming only 29% of the caloric requirement, and carbohydrate and fat are considerably low. To improve the diet, his diet would need to contain cheese, butter, milk, yoghurt, and more servings of cereals to match upto a caloric requirement of 3300 kcal per day. He can increase the fruit servings, reduce the meat, and increase the vegetables. His total carbohydrate intake should be 4 g per pound of body weight per day making 600 g of carbohydrate per day. This alters the cereal servings to about 1-1/2 pounds. This may be divided among vegetables, fruit juice, energy bar, health drink, sugars and the cereals depending on this athlete’s choices. The fats would better be unsaturated and from vegetable sources. He should consume 0.75 g of protein per pound of body weight per day. This makes 112 g of protein as against 60 g. Although his calcium intake is less, his iron intake is supernormal, and no iron supplementation is necessary. Risk of Injury: Since with such a diet, the balance is not maintained, the athlete is bound to lose body mass with training and event. This predisposes to injuries, such as, muscle trauma, fall, joint injuries due to deficiency of power. Due to his athletic activity, he would need to be guided on food habits. He should eat a large meal 4 to 6 hours prior to training or competition. A smaller meal 2 to 3 hours prior to competition would be better. Tack a snack, preferably fruit juices or energy bar ½ to 1 hour prior to training or event. After the performance, about ½ hour, he would take a snack. Another snack is advisable 2 hours after the performance. He needs water before, during, and after performance. Brief Explanation of Choice of Food: This athlete lives alone, does not have a car. He is student and cannot avail other resources of food. As a result, he depends on packed food. Thus lack of vehicle, lack of funds, and increased expense of packed items have invariable implications on his food selection. The factors of physical availability, economic availability, personal availability leads to the really available food for him. For example, at times it is very difficult to purchase food in small quantities, and constraints of funds and singleness promotes careful planning of procurement of food. His schedule is busy, and he has hardly any time to go for it. These factors combined together are perhaps hampering his nutrition. References Astrand, P.O. and Rodahl, K., Textbook of Work Physiology, 3rd ed., McGraw-Hill Book Co, New York, 1986. Bell, G.H., Emslie-Smith, D., and Paterson, C.R., Textbook of Physiology and Biochemistry, Churchill Livingstone, New York, 1976, 57–64. Bender, D.A., (2003). Nutritional Biochemistry of the Vitamins, 2nd ed., Cambridge University Press, Cambridge, U.K. Bowman, B.A. and Russell, R.M., Eds., (2002). Present Knowledge in Nutrition, 8th ed., International Life Sciences Foundation, Washington, D.C. Buzina, R., Grgic′, Z., Jusic, M., Sapunar, J., Milanovic, N. and Brubacher, G., Nutritional status and physical working capacity, Hum. Nutr. Clin. Nutr., 36C, 429, 1982. Clarkson, P.M., Exercise and the B vitamins, Ch. 7 in Nutrition in Exercise and Sport, 3rd ed., Wolinsky, I., Ed., CRC Press, Boca Raton, FL, 1998, 179. Fisher, A.G. and Jensen, C.R., Scientific Basis of Athletic Conditioning, Lea & Febiger, Philadelphia, 1991. Howley, E.T. and Franks, B.D., Health Fitness Instructor’s Handbook. Champaign:Human Kinetics, 1997. MacDougall, J.D., Wenger, H.A., and Green, H.J., Physiological Testing of the High-Performance Athlete. Champaign: Human Kinetics, 1991. McArdle, W.D., Katch, F.I., and Katch, V.L., Exercise Physiology: Energy, Nutrition and Human Performance, Williams & Wilkins, Baltimore, 1996, 139–213. National Research Council, (1989). Recommended Dietary Allowances, 10th ed., National Academy Press, Washington, D.C. Schoeller, D.A., Measurement of energy expenditure in free-living humans by using doubly labeled water, J. Nutr. 118, 1278–1289, 1988. Read More