Dietary Interventions: Participants will be asked to arrive fasting in the morning of the second (main) visit and will consume a standard meal (Chicken Hotpot from ASDA) with the same drink water at the evening before and the evening after the visit, as well as following a diet that excludes a list of specific foods containing high nitrate (rocket, spinach, other leafy vegetables, radish and beet root), cured meat, cured seafood and cured fish, mature cheese for 24hr prior to the study and fasting on the morning of the study.