Vegetarian Athletes Research Articles

Position of the New Zealand Dietetic Association (Inc): Nutrition for exercise and sport in New Zealand

Position of the New Zealand Dietetic Association (Inc): Nutrition for exercise and sport in New Zealand

Practical Suggestions for Vegetarian Athletes

Practical Suggestions for Vegetarian Athletes

Vegetarian Diets

The quality of vegetarian diets to meet nutritional needs and support peak performance among athletes continues to be questioned. Appropriately planned vegetarian diets can provide sufficient energy and an appropriate range of carbohydrate, fat and protein intakes to support performance and health. The acceptable macronutrient distribution ranges for carbohydrate, fat and protein of 45-65%, 20-35% and 10-35%, respectively, are appropriate for vegetarian and non-vegetarian athletes alike, especially those who perform endurance events. Vegetarian athletes can meet their protein needs from predominantly or exclusively plant-based sources when a variety of these foods are consumed daily and energy intake is adequate. Muscle creatine stores are lower in vegetarians than non-vegetarians. Creatine supplementation provides ergogenic responses in both vegetarian and non-vegetarian athletes, with limited data supporting greater ergogenic effects on lean body mass accretion and work performance for vegetarians. The potential adverse effect of a vegetarian diet on iron status is based on the bioavailability of iron from plant foods rather than the amount of total iron present in the diet. Vegetarian and non-vegetarian athletes alike must consume sufficient iron to prevent deficiency, which will adversely affect performance. Other nutrients of concern for vegetarian athletes include zinc, vitamin B12 (cyanocobalamin), vitamin D (cholecalciferol) and calcium. The main sources of these nutrients are animal products; however, they can be found in many food sources suitable for vegetarians, including fortified soy milk and whole grain cereals. Vegetarians have higher antioxidant status for vitamin C (ascorbic acid), vitamin E (tocopherol), and beta-carotene than omnivores, which might help reduce exercise-induced oxidative stress. Research is needed comparing antioxidant defences in vegetarian and non-vegetarian athletes.

A creatina como suplemento ergogênico para atletas

A creatina vem sendo muito pesquisada devido ao seu potencial efeito no rendimento físico de atletas envolvidos em exercícios de alta intensidade e curta duração, intermitentes e com curtos períodos de recuperação. A creatina fosforilada é uma reserva de energia nas células musculares. Durante um exercício intenso, a sua quebra libera energia é usada para regenerar o trifosfato de adenosina. Aproximadamente 95% do pool de creatina encontra-se na musculatura esquelética e sua regeneração após o exercício é um processo dependente de oxigênio. Estudos mostram que a suplementação com este composto pode aumentar o pool orgânico em 10 a 20%, e este percentual é maior em atletas vegetarianos (até 60%). Ainda existe controvérsia com relação aos benefícios e riscos da suplementação com esta substância. Este estudo revisa alguns dos aspectos relacionados com o metabolismo da creatina e seu uso como substância ergogênica na prática desportiva.

Physical fitness and vegetarian diets: is there a relation?

The available evidence supports neither a beneficial nor a detrimental effect of a vegetarian diet on physical performance capacity, especially when carbohydrate intake is controlled for. Concerns have been raised that an emphasis on plant foods to enhance carbohydrate intake and optimize body glycogen stores may lead to increases in dietary fiber and phytic acid intake to concentrations that reduce the bioavailability of several nutrients, including zinc, iron, and some other trace minerals. There is no convincing evidence, however, that vegetarian athletes suffer impaired nutrient status from the interactive effect of their heavy exertion and plant-food based dietary practices to the extent that performance, health, or both are impaired. Although there has been some concern about protein intake for vegetarian athletes, data indicate that all essential and nonessential amino acids can be supplied by plant food sources alone as long as a variety of foods is consumed and the energy intake is adequate. There has been some concern that vegetarian female athletes are at increased risk for oligoamenorrhea, but evidence suggests that low energy intake, not dietary quality, is the major cause. In conclusion, a vegetarian diet per se is not associated with improved aerobic endurance performance. Although some concerns have been raised about the nutrient status of vegetarian athletes, a varied and well-planned vegetarian diet is compatible with successful athletic endeavor.

Influence of dietary iron source on measures of iron status among female runners.

The purpose of the present investigation was to determine whether female runners who consume a modified vegetarian diet are predisposed to iron deficiency. Two groups of female runners who were matched for age, weight, aerobic capacity, miles run per week, and number of pregnancies were obtained for this study. One group (N = 9) regularly consumed a modified vegetarian diet (MV, less than 100 g red meat.wk-1), while the other group (N = 9) consumed a diet which included red meat (RM). Serum ferritin values were significantly (P less than 0.05) lower for the MV group (X +/- SE, 7.4 +/- 1.4 ng.100 ml-1) than for the RM group (19.8 +/- 4.2 ng.100 ml-1). Total iron binding capacity (TIBC) of the serum was also significantly different between the two groups of subjects (MV, 366.5 +/- 12.2 micrograms.100 ml-1; RM, 327.2 +/- 9.6 micrograms.100 ml-1). While dietary iron intake was comparable for the two groups (MV, 14.7 +/- 2.0 mg.d-1; RM, 14.0 +/- 2.2 mg.d-1, the bioavailability of the dietary iron was significantly different (MV, 0.66 +/- 0.08 mg.d-1; RM, 0.91 +/- 0.10 mg.d-1). As the presence of heme iron (from meat, fish, and poultry) increases the bioavailability of dietary iron, the results of the present investigation suggest that vegetarian athletes have altered iron status due to the form in which their dietary iron is consumed.