4. Discussion
This study aimed to illuminate the effects of nitrate supplementation on performance depending on different baseline levels of athletes’ habitual dietary nitrate intake, as well as how athletes could cover their nitrate needs from whole foods alone without the use of nutritional supplements, on a sample of elite football players from the First Division of Slovenian football.The results of this study indicate that nitrate supplementation has a statistically significant positive effect on performance if dietary nitrate intake is below 300 mg, which is regarded as an effective ergogenic dose [Overall, the results of this study are in line with previous reviews [Looking at individual numbers, there was some conflicting evidence to be observed. For instance, participant 3 (Comparing the performance within subjects with a high baseline intake of nitrates (>300 mg) was meant to give a further insight into the relationship between dietary nitrate intake and performance. We hypothesized that nitrate supplementation would not have a significant positive effect on covered distance in the Cooper performance test compared to the placebo if the baseline dietary nitrate intake was high (>300 mg nitrates) in the placebo group, as this would indicate that participants had already ingested enough nitrates through their diet to elicit ergogenic benefits. However, the sample size was too small to obtain a definitive answer. Looking into the results of the two participants (participant number 14 and 15, The average nitrate intake from whole foods from football players in this study was 165 mg. This is a greater intake than that reported by Jonvik et al. (2017), where the median dietary nitrate intake was 106 mg in a large group (n = 553) of highly trained Dutch athletes [Perceived exertion was measured using a 6-to-20-point Borg scale [The average VO2max of the participants was 54.1 mL/kg/min, with the lowest recorded value being 44.1 mL/kg/min (playing position: goalkeeper) and the highest recorded value being 67.4 mL/kg/min (playing position: midfielder). This range is quite high; however, it was not unexpected due to the different playing positions of the football players. VO2max is often regarded as the best indicator of aerobic capacity [Noteworthily, none of the athletes in this study had previously used beetroot juice or nitrate supplements of any kind prior to the study. Some of the athletes reported having heard that beetroot juice could be beneficial but had no knowledge of how and why beetroot juice should be or could be used in the context of improving sports performance. This highlights the need for more structured sports nutrition counseling in the First Division of Slovenian football, which is in line with our previous research on nutrition in elite football players [