Study Limitations
There are several limitations to this study. Firstly, the results of this study refer to a small group of Slovenian football players aged 19–31. A strong limitation of this study was also the small sample size in regard to examining the effects of nitrate supplementation when the baseline nitrate intake already exceeds 300 mg (Hypothesis 2). The limitations also include the reliability and validity of the estimation of average dietary intake. As with most food tracking in research, some participants may have under-reported, and others may have over-reported, their intake of certain foods. However, the research team did their best to minimize these effects by providing visual cues for food logging and assembled dishes as well as working with each participant individually to report their nutrition as accurately as possible. Another possible limitation includes the calculation of nitrate intake from participants’ food diaries. We included data based on the PRODI