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Sport nutrition Vegetarian diet for exercise, athletic training and performing HEIDI M. AARSBY, D. ENETTE LARSON-MEYER* *Corresponding author Department of Family and Consumer Sciences Dept 3354 1000 E University Ave Laramie, WY 82071, USA INTRODUCTION Anno 17 - No. 2 n March/April 2006 n AgroFOOD industry hi-tech XX An apparently increasing number of athletes are adopting vegetarian diets for health, ethical (animal rights), ecological, environmental and religious or spiritual reasons. Some coaches and professionals, however, commonly express concern that vegetarian athletes may not receive the proper nutrition required for optimal training and performance. In truth, vegetarian athletes -from recreational to elite-can meet their energy and nutrient requirements on the various types of vegetarian diets (Table 1). Like most athletes, vegetarian athletes may benefit from education about food choices to optimize their health and ABSTRACT Optimal athletic performance requires optimal nutrition. It has been a concern for some coaches and professionals that vegetarian athletes may not receive the proper nutrition required for optimal performance. However, if these athletes are educated on proper nutrition, their energy, carbohydrate, protein and fat needs can easily be met. Vegetarians must also make sure they ingest adequate amounts of nutrients that are found less abundantly in vegetarian foods or are less well absorbed from vegetarian compared to omnivorous diet. These nutrients include: calcium, iron, zinc, iodine, vitamin D, vitamin B-12, and riboflavin. Those working with vegetarian athletes should understand the athletes' reasons for being vegetarian and properly educate them on nutrient sources that fit their personal beliefs and values. peak performance. This article will discuss the energy and macronutrient needs of athletes and active individuals, address the specific vitamins and minerals that may be lacking in a poorly selected vegetarian diet, and review the nutrition recommendations for before, during, and after exercise. Lastly, a few tips for professionals to consider when working with vegetarian athletes are addressed. ENERGY AND MACRONUTRIENTS athletes' diet and should make up the bulk of their energy intakes (3). Carbohydrate ingestion is essential for optimal performance during prolonged exercise periods, including extended stop-and-go activities (4-13). Carbohydrates are also necessary for glycogen repletion following exercise (3, 14, 15). The amount of carbohydrates athletes and active vegetarians need to ingest varies, depending on sport, intensity, gender, and body weight. Based on research findings in mostly male populations, it is currently recommended that athletes ingest 6 to 10 grams of carbohydrate for every kilogram of body mass (g/kg/day) (3). For example, an athlete that exercises at a high intensity for longer periods of time would need to ingest more carbohydrates than an athlete who did high-intensity exercises for a shorter amount of time. Vegetarian athletes, like all athletes, should be educated on proper types of carbohydrates to eat surrounding an exercise session (Table 2 and Table 3). Energy requirements of athletes are variable due to the large array of sports, activities and intensities at which athletes can exercise. Other influencing factors include age, gender, and body composition. There is some concern that vegetarian, especially vegan, athletes may not meet their energy needs due to the high-fiber and lowenergy density of plant-based diets (1). Therefore, athletes with high energy needs should strive to consume regular meals and snacks that include some low-bulk, high-density foods in order to ensure adequate intake. Vegetarians can Table 1. Types of vegetarian diets easily accomplish adequate intake by consuming: fruit juice rather than whole fruit and about one-third to one-half of their breads, cereals, and grains as more refined sources, such as white rice or sourdough bread rather than whole wheat rice or bread (1, 2). Carbohydrates are an important Table 2. Suggested nutrient and fluid intake before, during, and after exercise component of the Vegetarian athletes are capable of reaching their needed energy and nutrient intakes with planning (16). The March/April 2006 n Anno 17 - No. 2 Vitamins and minerals are an essential part to any person's diet. Vegetarian athletes may need to pay particular attention to a handful of nutrients which are either found less abundantly in vegetarian foods or are less well absorbed from vegetarian compared to omnivorous diet. These nutrients include calcium, iron, zinc, iodine, vitamin D, and some of the B-vitamins (B-12 and Table 4. Approximate protein content of selected vegetarian food riboflavin). Other sources nutrients including potassium, magnesium, folate, vitamins Unlike previously thought, vegetarians A, C, E, and K are provided abundantly do not need to consume a certain by a well balanced vegetarian diet (3, combination of plant-based protein at 16). each meal in order to receive all Calcium intake is a concern for vegan essential amino acids. More importantly, n VITAMINS AND MINERALS XXI AgroFOOD industry hi-tech Protein requirements vary according to training level and type of activity. A very active athlete will need more protein than a recreational exerciser that only exercises a few days a week. The Recommended Dietary Allowance (RDA) in the United States is 0.8 g/kg/day. This will meet the needs of most people who exercise at a light to moderate intensity most days of the week. But, athletes who train at higher intensities will likely need more protein. The recommendation for endurance athletes is 1.2 to 1.4 g/kg/day and for resistance-trained athletes, the recommendation can be as high as 1.6 to 1.7 g/kg/day (3). Vegetarian athletes, especially vegans, may need more protein than their nonvegetarian counterparts because plantbased protein may be less bioavailable than animal-based protein. Therefore, more protein may be needed to account for this difference. Thus, the suggested protein intake for vegetarian athletes is 1.3 to 1.8 g/kg/day (3). Athletes can meet needs by consuming a variety of plant-based protein foods and ensuring adequate energy intake. Good sources include soy products (tofu, tempeh, veggie burgers, soy dogs, and other meat analogues), legumes, nuts and nut butters, and seeds (Table 4). athletes and vegetarians who consume minimal dairy products. To ensure adequate calcium intake, these athletes need to include several servings of well absorbable calcium-rich plant-based sources (24-26) (Table 5). Vitamin D, which aids in calcium absorption is also a concern due to reduced intake of Vitamin D fortified foods and limited sun exposure (particularly in indoor-sport athletes) (27). Vitamin D requirements can be met by spending just a few minutes outside in shorts several times a week (if Caucasian). Taking vitamin D in food or as supplements is wise for dark-skinned athletes and in winter months for all athletes (28). Vegans, however, should be warned because the vitamin D3 (chocalciferol) used to fortify some products is of animal origin (2, 16) and the vitamin D2 form (ergocalciferol) - often referred to as the vegetarian vitamin D - may not be as effective at increasing vitamin D status (2, 16, 29). Iron intake, especially for females, can be a concern for vegetarian athletes as well. Non-heme iron (plant-based iron) is best absorbed with foods that contain ascorbic acid (i.e. citrus fruit or juice, tomatoes, and melon) and other organic acids and is inhibited by plant phytates, polyphenolics, tannins in tea, cocoa and coffee, soy and dairy protein, and foods with high concentrations of calcium, zinc or other divalent cations (30, 31). Cooking with iron cookware also boosts iron content, particularly when the foods are slightly acidic (i.e. tomato sauce). If iron status is a concern, athletes should see a doctor to determine whether iron supplementation is truly needed. General use of iron supplements is not recommended due to the high risk of hemochromotosis (32). Athletes seem to show a decreased zinc status (33), therefore vegetarian athletes need to consume a variety of whole grains and legumes daily (3, 33-35). This is particularly important because like iron, zinc is less well absorbed in plant-based foods and is not found as abundantly in vegetarian sources (16, 35). Iodine is another red flag mineral for many vegans and vegetarians who avoid table salt (typically fortified with iodine) or consume plant foods grown in iodinepoor soil (36-38). Lastly, selected Bvitamins especially B-12 and riboflavin, may be of concern to vegan and vegetarians who limit intake of dairy (39). The best sources of these vitamins and minerals for vegans and vegetarians can be found in Table 5. SUMMARY AND PRACTICAL TIPS Sport nutrition Table 3. Carbohydrate sources that contain approximately 15-20 g CHO per serving1 a wide range of protein throughout the day should be consumed (16, 17). Most athletes who meet energy needs and consume a wide variety of protein will meet the required protein needs. But those athletes participating in heavy resistance training, which increases protein needs more so than energy demands, may need to take special care to include high quality plant-based protein at most meals and snacks. Dietary fat is also an essential part of the diet. It should make up the remainder of the energy intake, after carbohydrates and proteins (3). Dietary fat is necessary in order to provide energy and essential fatty acids, and to aid in the absorption of fat-soluble vitamins (3). Fat stored within active muscle and adipocytes are used as a substrate during prolonged exercise of moderate intensity and during low-level activity (18-20). Some vegetarian athletes tend to eat high carbohydrate diets and inadequate fat. Very low-fat diets may not be appropriate for athletes with a heavy training load and may compromise triglyceride stores within the muscle fibers (21-23). These athletes should be informed on how to incorporate foods high in mono- and polyunsaturated fats into their diets. These types of fat can be found in foods such as avocados, nuts and seeds, olives and olive oil, and flax and sesame oil. Sport nutrition Anno 17 - No. 2 n March/April 2006 n AgroFOOD industry hi-tech XXII athlete should take extra care to ingest some of the key nutrients discussed in order to meet their requirements. Thus, it is the responsibility of professionals, coaches, and trainers to understand the athlete's reasons for being a vegetarian (40), be sensitive to each individuals' needs, and properly educate vegetarian athletes on sources of both macro- and micronutrients mentioned that fit their personal beliefs and values. The professionals need to make sure the athletes are not claiming vegetarianism in order to mask eating disorders (41, 42). Eating disorders are serious mental illnesses that can impair health and athletic performance. Lastly, the athletes should never be told that they have to eat animal products in order to obtain adequate nutrition. The following are a few tips to give athletes when instructing them on nutrition. - Meeting energy requirements is crucial to obtain proper nutrition and optimal performance. - Carbohydrates are essential for maximizing and restoring glycogen stores after exercise. Athletes should consume 6 to 10 grams of carbohydrate/kilogram body mass/day. Carbohydrate sources include grain products, fruits, juices, starchy vegetables, added sugars, and sports supplements (Table 3). - Protein requirements vary depending on exercise type and intensity. 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