CONSUMPTION OF POTATOES AND THEIR CONTRIBUTION TO DIETARY NITRATE ANDNITRITE INTAKES

Present in food and drinking water, nitrates are readily converted in mammalian systems to nitrites which can react with amines, amides and aminoacids to form N-nitroso compounds. In this study, we evaluated 1) the contribution of potatoes to dietary intakes of nitrate and nitrit e, 2) the consumption of different forms of potatoes, 3) the impact of cooking treatments on nitrate and nitrite concentrations in peeled or non-peeled potatoes. For the evaluation of nitrate and nitrite intake s, a food frequency questionnaire including 47 food groups and 90 food items, was administered to 255 consumers of well water in Portneuf, l ie d'Orleans, Lanaudiere and Nicolet (Quebec, Canada). Consumption of different forms of potatoes was evaluated by means of a survey on 1002 Quebecers, Also, boiled, oven cooked and fried potatoes (Superior cul tivar) were analyzed for nitrates and nitrites using ion exchange chro matography. The average contribution of potatoes to daily nitrate inta ke was 14,4% and to nitrite, 9,2%. Furthermore, peels contained a high er concentration of nitrate than the flesh; however, the concentration of nitrite was not different. Boiling in water drastically reduced ni trate concentration in potatoes, whether peeled or not.