Vegetarians by definition are individuals who choose not to eat meat, poultry, game or fish, and refrain from by-products such as gelatin, rennet, and animal fats. The vegetarian diet varies widely but in general comprises a large proportion of cereals grains, fruit, vegetables and other carbohydrates, proving rich in fibre, carotenoids, and vitamins C and E. Conversely it risks a lack of protein, saturated fat, and vitamin B12, and several other vitamins and minerals including zinc, calcium and riboflavin.
Physical activity depends on appropriate nutrition, and the balanced consumption of adequate micro and macronutrients. Fundamentally an athlete’s diet must comprise sufficient macronutrients for energy demands to be met, which will depend on athletes individual body composition and size, gender, training programme and type and intensity of the sport in question. Specifically vegetarians need to address their intake of protein and carbohydrate to ensure they are fuelling and recovering from training and competition efficiently.
The protein guidelines discussed according to sport and/or type of activity is relevant to all vegetarians. In theory, a vegetarian athlete should have no problem consuming this volume from a variety of dairy and plant based protein sources. Where attention may need to be focused is on the quality of proteins being consumed with a risk to vegetarians of limiting consumption of some essential amino acids, specifically lysine, threonine, tryptophan and sulpher containing amino acids. Attention must therefore focus on ensuring sources of protein with content of these particular amino acids similar to meat sources are consumed, these being primarily eggs, chickpeas, soya beans, wheat and nuts.
A vegetarian diet can easily provide the recommended carbohydrate intake for athletes to maintain muscle glycogen concentrations. All athletes should ensure that sufficient nutrient intake is consumed to meet the energy demand of their individual training and competition schedule.
Iron is one of the micronutrients that has the potential to detriment athletic performance if an inadequate amount is consumed. Iron is required for the construction of hemoglobin and myoglobin (oxygen carrying proteins), and also for enzymes catalyzing reactions within energy pathways. One of the most frequently observed micronutrient deficiencies is that of iron, especially within female athlete populations and those following a vegetarian diet due to the low bioavailability of this nutrient in vegetarian foods. Due to differences in bio-availability of iron across foods groups, the RDA for iron in vegetarians is increased by 80% – 14mg/day and 32mg/day for men and women respectively. A key watch out for vegetarians is that they might inadvertently be inhibiting their iron absorption further by consuming high levels of phytic acid contained in legumes, lentils, nuts, soy proteins and whole grains.
Adequate intake of B-complex vitamins is essential to facilitate efficient energy production and the construction and repair of new muscle tissue. Specifically vitamin B12 plays a role in the production of red blood cells and protein synthesis. A vegetarian diet severely restricts intake of naturally occurring B12, risking anaemia. It is therefore recommended that the vegetarian athlete consume fortified foods or supplements to ensure they meet the RDA for vitamin B12 of 2.4mcg.day. Such sources could include fortified breakfast cereals, cheese, eggs, milk and yoghurt, and of course quality dietary supplements.
Other vitamins and minerals generally found in animal based foods include zinc, riboflavin and calcium can also be provided in ample quantities as long as vegetarians source a range alternatives from which to source them.
Creatine is a non essential naturally occurring amino acid based compound, contained in meats and fish. It can also be synthesized in the liver. It is reasonable to suggest that vegetarians consuming a naturally low intake of creatine will have lower muscle creatine stores, and the effect of appropriate supplementation could be more prominent that in athletes that eat meat.
The travelling vegetarian athlete may need to consider availability of appropriate foods in various countries/continents. Restaurants may have limited choices and appropriate snacks may not be widely available so planning and travelling fully equipped with extra food choices or supplements may be wise.