Evaluation of the relationship between nutrition knowledge levels, caffeine consumption and body composition of professional soccer and professional volleyball players

There is a strong relation between training and nutrition for athletes to achieve a high level of exercise performance and nutritional knowledge, is aimed to affect modifiable factors such as food intake and body composition positively. The aim of this study was to compare the nutritional knowledge levels of professional footballers and professional volleyball players, to determine their nutritional status, and to evaluate the relationship between caffeine intake and body composition. It was conducted on a total of 43 professional male athletes aged 18-35, 19 professional football players who played in a football team of Turkish Football Federation 1. League between the dates December 2019 – March 2020 and 24 professional volleyball players from two different volleyball teams of Turkish Volleyball Federation. A questionnaire was applied to the participants in order to determine their sociodemographic characteristics, general characteristics, dietary habits and caffeine intake. In order to evaluate the energy and nutrient intake, the athletes' 1 day on training, 1 day of match day and 1 day off training records were obtained by face to face interview technique for 3 consecutive days of food consumption and physical activity. Anthropometric measurements and body compositions were determined by the researcher. Nutritional knowledge levels of the participants were determined by Turkish version of the Nutrition for Sport Knowledge Questionnaire (NSKQ). The average NSKQ score of footballers and volleyball players was found as 23.57 ± 4.64 and 17.29 ± 8.20 points, respectively, over 68 points (p<0.05) and it was determined that all of the participants had a "weak knowledge" level about sports nutrition. Total caffeine intake of footballers and volleyball players was on avarage found as 295.47 ± 69.73 mg and 347.53 ± 238.62 mg, respectively (p> 0.05). A negative relationship between football players' caffeine consumption and body weight and a positive relationship between footballers' body fat percentage and body fat mass has been found and it has been determined a negative relationship between volleyball players caffeine consumption and body weight, body fat mass and body fat percentage (p> 0.05). Energy, carbohydrate and fat intake of footballers on training, match and off days were found to be higher than volleyball players (p <0.05). It is determined that the percentage of energy coming from protein and fat is high in both footballers and volleyball players. Football players' intake of vitamin A, vitamin E, thiamine, riboflavin, folate, vitamin C, B6 and B12, potassium, calcium, magnesium, phosphorus, iron and zinc were higher than volleyball players. It was determined that the intake of micronutrients on the day of training was sufficient or high according to the Dietary Reference Intake Level (DRI) recommendations, while the intake of calcium on the day of the match and folate, calcium and magnesium intake on their off day were insufficient. It was determined that the intake of thiamine, folate, vitamin C, potassium, calcium and magnesium was insufficient on the day of training, match and off day of volleyball players. As a result of the high daily consumption of vitamin B12, phosphorus, iron, and zinc, food consumption from animal origin was found to be above the recommendations. When food groups consumption of football players and volleyball players evaluated suggestions of the Turkey Dietary Guidelines (TÜBER), it was determined that the consumption of milk group, fish, legume / oilseed, cereal group and vegetable-fruit group in general was insufficient. Consequently, this study is used to overcome the nutritional deficiencies of footballers and volleyball players and to increase the need in this field, to positively affect their eating habits and accordingly to improve their sports performance.