## 4 Discussion  
This is the first study to evaluate the effect of a preparation containing organic beet leaves and stalks on postprandial oxidative stress in humans. For this, we first compared the compositions of conventional and organic beet leaves and stalks to then select the best sample for the clinical trial. A significant difference was observed in the composition of the humidity, macronutrients and polyphenols between the conventional and organic leaves and stalks. However, only the organic stalk showed a significantly higher concentration of polyphenols compared with the conventional stalks. In organic cultivation, chemicals are not used to protect against pests. Therefore, the plants synthesize phenolic compounds, which will act as a natural defense for the plant [28; 29], which then justifies the higher content of these compounds in the organic stems compared with the conventional ones. Regarding the carbohydrate content, the organic stalks had higher carbohydrate contents than the conventional ones, while the results found in the leaves were the opposite. One of the explanations for the greater amount of carbohydrates in organic stalks may be the fact that organically grown soils can be more balanced and fertilized, thus obtaining a greater amount of raw material for the production of nutrients by the plant [30]. Furthermore, according to [PERSON] and [PERSON] (2013) [31], the concentration of photoassimilates, called sugars, is positively correlated with the rate of photosynthesis. As photosynthesis takes place, the products of this process are exported from photosynthetic organs (in this case, the leaves) to the regions of the plant that import photoassimilates (in this case, the stalks). In organic cultivation, there may have been a higher rate of photosynthesis and consequently greater translocation of photoassimilates from the leaves to the stems, which may explain the carbohydrate contents found in the analyses. The fertilization method and soil nutrition can also influence the protein content found in vegetables. When the plant has nitrogen in significant amounts, protein synthesis is increased [32], which may explain the higher protein content found in organic leaves and stems compared with conventional ones. For organic cultivation, earthworms were used in the plantation. The humus produced by earthworms is considered a natural fertilizer, having nitrogen in its composition and helping to increase the production of proteins by the organic vegetable [33]. In conventional cultivation, NPK-based fertilizers are used, which are fertilizers composed of three important macro-elements for the plant, namely nitrogen, phosphorus and potassium. The nitrogen present in this fertilizer, together with phosphorus, has the purpose of increasing protein synthesis in the plant. However, the correct management of nitrogen fertilization is extremely important, since nitrogen is one of the most easily leached elements, which may explain the lower concentration of proteins in the conventional leaves and stems compared with the organic leaves and stalks despite fertilization [34]. For the lipid content, the average found in the organic and conventional leaves was 1.06 g/100 g and 0.98 g/100 g, respectively, while in the stalks it was 0.17 g/100 g for the organic ones and 0.31 g/100 g for the conventional ones. These results show that these parts can be used in preparations without raising the lipid content. Furthermore, leaves and stalks, when compared with the noble part of the food, do not present significant variations from a functional point of view in the amount of this nutrient, since fruits and vegetables are not sources of lipids [35]. Due to the superiority presented by the organic leaves and stalks, the clinical study was carried out with the organic product. The major compound found in the organic BLS juice was vitexin-2-O-rhamnoside.