Abstract
An increase in the level of nitric oxide (NO) plays a key role in regulating the human cardiovascular system (lowering blood pressure, improving blood flow), glycemic control in type 2 diabetes, and may help enhance exercise capacity in healthy individuals (including athletes). This molecule is formed by endogenous enzymatic synthesis and the intake of inorganic nitrate (NO(3)(-)) from dietary sources. Although one of the most well-known natural sources of NO(3)(-) in the daily diet is beetroot (Beta vulgaris), this review also explores other plant sources of NO(3)(-) with comparable concentrations that could serve as ergogenic aids, supporting exercise performance or recovery in healthy individuals. The results of the analysis demonstrate that red spinach (Amaranthus spp.) and green spinach (Spinacia oleracea) are alternative natural sources rich in dietary NO(3)(-). The outcomes of the collected studies showed that consumption of selected alternative sources of inorganic NO(3)(-) could support physical condition. Red spinach and green spinach have been shown to improve exercise performance or accelerate recovery after physical exertion in healthy subjects (including athletes).