## 1 Introduction  
The postprandial state is a period of dynamic metabolism in which the transport, biosynthesis and metabolism of dietary components such as glucose, lipids and proteinsoccurs. During this period, the organism responds to short-term disturbances with adaptive mechanisms in order to restore homeostasis [1; 2]. However, the consumption of high-energy meals, together with the consumption of several meals during the day, contributes to a greater formation of reactive oxygen species (ROS) or reactive nitrogen species (RNS). At this stage, the imbalance between the formation of ROS, RNS and antioxidants in favor of oxidants can potentially lead to a condition called postprandial oxidative stress [2], which can cause cellular dysfunction and biological damage.  
The consumption of meals with excessive amounts of lipids, especially saturated fats, is one of the factors that contributes significantly to this acute state of imbalance by triggering a significant increase in the serum triglyceride (TG) concentration. Hypertriglyceridemia leads to the formation of smaller and more atherogenic low-density lipoproteins (LDLs). When taken from the subendothelial space, these lipoproteins boost an inflammatory process which increases the production of ROS, therefore increasing oxidative stress and, consequently, increasing the risk of cardiometabolic diseases [3].  
In response to excessive ROS production, the organism has an endogenous (antioxidant enzymes) and exogenous (flavonoids, \(\alpha\)-tocopherol, carotenoids and vitamin C, among others) antioxidant system that neutralizes these reactive species by preventing free radicals from taking electrons [4]. Therefore, an adequate supply of antioxidants from meals consumed throughout the day could reduce postprandial oxidative stress [5]. In this context, red beetroot (_Beta vulgaris_ L.) has been widely studied due to its high content of antioxidants [6]. It is a plant in which the roots, stalks and leaves are good sources of bioactive compounds, including phenolic compounds, which have already been associated with oxidative stress modulation in experimental studies [7].  
Recent experimental studies showed that beet leaves and stalks could be used as adjuvant in dietary-induced obesity in mice to reduce the damage generated by oxidative stress and to improve parameters related to glucose homeostasis, including fasting glucose and glucose tolerance [8; 9]. Beyond that, vitexin and its derivatives were the major bioactive compounds present in beet leaves and stalks. It has a wide range of pharmacologic effects, including antioxidant, anti-cancer, anti-inflammatory and neuroprotective effects [9; 10].  
However, to date, no studies have reported the effects of beet leaves and stalks on oxidative stress in humans. In addition, the polyphenol content of the beet can vary according to conventional or organic cultivation [11; 12], and there is evidence that the antioxidants present in leaves and stalks of beets overlap that of the root, a fact that should be considered to encourage the use of alternative edible parts of food, reducing food waste [7; 13].  
Therefore, the aim of this study was to evaluate the differences in the nutritional composition and the concentration of total phenolics between organic and conventional beet leaves and stalks. From these results, we then verified whether the ingestion of beet leaves and stalk juice with different concentrations of polyphenols could modulate some oxidative stress markers and an inflammatory marker after consuming a high-fat meal in individuals with dyslipidemia.