Common Japanese vegetables, identified as the daily source of nitrate [29] and [30], were encouraged to consume during the consequent 10 days. To avoid the concentration differences in nitrate/nitrite in locally produced foods, the participants were provided with fresh vegetables and staple foods from the same store twice a week during both intervention periods. During the control period, participants were instructed to avoid these vegetables. Instead, the study subjects received and followed the instructions how to replace traditional Japanese meals; for example, by having cornflakes, muesli, yogurt or sandwiches for breakfast. The control diet was designed to eliminate the risk of any major differences between diets in total protein, carbohydrates, saturated and unsaturated fat. The control diet was controlled for nitrate and nitrite sources and those were excluded from the consumption. The mean total intake of energy was approximately 1900 kcal per day.