# Old-Fashioned, but Still a Superfood--Red Beets as a Rich Source of Bioactive Compounds
## 7 Other Compounds  
Nitrate (NO\({}_{3}\)\({}^{-}\)) is one of the most important inorganic compounds in red beets, and their ingestion provides a natural means of increasing in vivo nitric oxide (NO) [8]. This can prevent several pathologies such as hypertension and endothelial dysfunction [78; 79]. For a long time, nitrates, which can be converted into nitrosamines, were thought to be harmful substances. These, in turn, lead to endocrinological diseases, defects in human fetuses or cancer [80]. Today it is known that red beetroot nitrates are one of the most important nutrients. In general, nitrates provide ergogenic and cardio-protective properties. Nitrates present in beetroots are converted into nitrite and nitric oxide, which are responsible for lowering blood pressure and vasoprotection [81]. [PERSON] et al. reported that beetroot juice lowers blood pressure to a greater extent than sodium nitrate [82]. Many studies have focused on the impact of beetroot juice consumption on the body's efficiency, mainly during intense physical exercise. [PERSON] et al. performed a randomized, clinical, crossover, double-blind study which has shown that the consumption of 140 mL of juice from red beets improved macrovascular endothelial function [83]. However, no oxygen saturation parameters in muscle tissue of pregnant women were observed. Other studies showed that one week of supplementation with beetroot juice improved submaximal endurance and reduced blood pressure in older patients with heart failure and preserved ejection fraction [84]. Subsequent works emphasize the beneficial effect of beetroot supplementation on the body's efficiency during physical exertion, as well as its impact on the speed of regeneration [85; 86]. The content of nitrates in beetroot depends on its variety. [PERSON] et al. analyzed nitrates content in seven beetroot varieties grown in Upper Austria [49]. The highest content was detected in the Mona Lisa variety (4626 \(\pm\) 568 mg\(\cdot\) L\({}^{-1}\)), while the lowest was found in Robuschka (564 \(\pm\) 129 mg\(\cdot\) L\({}^{-1}\)). The mean value across all analyzed cultivars was 1970 mg\(\cdot\) L\({}^{-1}\), but the established standard deviation was 1395 mg\(\cdot\) L\({}^{-1}\), which demonstrates the variability of nitrate content among beet varieties. [PERSON] and [PERSON] studied the nitrate and nitrite content of beet juice products marketed to athletes [87]. The NO\({}_{3}\)\({}^{-}\) concentration of powders was significantly higher than that of concentrates (174 \(\pm\) 63 umol\(\cdot\)g\({}^{-1}\) and 70 \(\pm\) 39 umol\(\cdot\) mL\({}^{-1}\), respectively). A lower concentration of nitrates was found in mixed drinks (13 \(\pm\) 5 umol\(\cdot\) mL\({}^{-1}\)) and bulk juices (18 \(\pm\) 11 umol\(\cdot\) mL\({}^{-1}\)). Authors highlighted that regardless of the type of product, there was considerable variability in NO\({}_{3}\)\({}^{-}\) concentration/content between products and, often, between samples of the same product [86]. The evaluation of nitrate and nitrite contents of beetroot from different regions of Brazil and the USA showed the highest nitrate (31.2 \(\pm\) 0.010 mmol\(\cdot\) L\({}^{-1}\)) and nitrite (0.45 \(\pm\) 0.005 mmol\(\cdot\) L\({}^{-1}\)) contents in US beets when compared to beetroots from Brazil [88]. In Brazil, Rio de Janeiro was the region that showed the highest nitrate content (17.1 \(\pm\) 0.02 mmol\(\cdot\) L\({}^{-1}\)), while Rio Grande do Norte presented the highest nitrite content (0.13 \(\pm\) 0.010 mmol\(\cdot\) L\({}^{-1}\)). Red beetroots have more sugar than many other vegetables. According to [PERSON] et al., its average total content was 77.5 \(\pm\) 10.2 g\(\cdot\) L \({}^{-1}\) (7.8%) [49]. In the roots, sucrose was the most commonly identified sugar (94.8%), followed by glucose (3.3%) and fructose (1.9%). However, glucose was the major sugar in the shoots [89]. Red beetroot can be considered as a part of a healthy diet for diabetic patients.