Nitrate in vegetables: toxicity, content, intake and EC regulation

Abstract

Nitrate content is an important quality characteristic of vegetables. Vegetable nitrate content is of interest to governments and regulators owing to the possible implications for health and to check that controls on the content are effective. Nitrate itself is relatively non-toxic but its metabolites may produce a number of health effects. Until recently nitrate was perceived as a purely harmful dietary component which causes infantile methaemoglobinaemia, carcinogenesis and possibly even teratogenesis. Recent research studies suggest that nitrate is actually a key part of our bodies' defences against gastroenteritis. In this review are reported: (1) vegetable classification as a function of nitrate accumulation; (2) vegetable contribution to the total dietary exposure of nitrate; (3) European Commission Regulation No. 563/2002 which sets limits for nitrate in lettuce and spinach; (4) the maximum levels set in some countries for beetroot, cabbage, carrot, celery, endive, Lamb's lettuce, potato, radish and rocket; (5) the results of surveys on the nitrate content of vegetables in Italy and other European countries.

Rosemary extract and celery-based products used as natural quality enhancers for colonial type salami with different ripening times

“…Celery (Apium graveola) is a leafy plant with significant levels of nitrites and nitrates (SANTAMARIA, 2006); it is a possible natural source of these compounds for use in cured/ fermented products. Its effects in cooked and cured products were studied by Sindelar et al (2007a, b), who demonstrated the potential for such use although additional studies are needed.…”

Evaluation of the nitrate and nitrite content of vegetables commonly grown in Slovenia

“…The role of nitrites in the formation of carcinogenic nitrosamines has led to some public apprehension about the nitrite content of our food (Knobelock et al, 2000). The nitrate (NO3 -) nitrogen (N) form has a low level of acute toxicity but it can be transformed into the nitrite N (NO2 -) form, which has much higher acute toxicity (Santamaria, 2006). It has been estimated that about 4-8% of the nitrate from the diet may be reduced to nitrite by the micro flora in the oral cavity (Ashby, 2008;Lundberg and Weitzberg, 2009).…”

“…(Cavaiuolo and Ferrante, 2014), contain nitrate at significant levels. These vegetables often contain nitrate concentrations above 2500 mg kg -1 , especially when they are cultivated in greenhouses (Santamaria, 2006). On the other hand, the nitrate content of vegetables can also be affected by the geographical region, day (light) intensity and duration, soil texture, soil temperature, humidity, density of plants in the field, vegetation period, season of harvest and processing time (Guadagnin et al, 2005;Tamme et al, 2006;Weigtman et al, 2006;Parks et al, 2012).…”

“…To protect human health, most European countries have regu-N o n c o m m e r c i a l u s e o n l y lated the nitrate content in food (Santamaria, 2006 (Hmeljak and Cencič, 2013). The objective of the research was to determine nitrogen forms and nitrogen rates of nitrate accumulation in various vegetable samples commonly grown in Slovenia and to compare them with relevant legislation.…”

Response of Nitrogen Metabolism in Pak-choi Plants Treated with Different Sodium Selenate (Na₂SeO₄) Concentrations

“…Pak-choi is one of the main leafy vegetables cultivated year-round. NO 3 − is part of the nitrogen (N) cycle in nature (Santamaria, 2006), and its accumulation in plants differs among types and varieties owing to genetics (Martignon et al, 1994;Reinink et al, 1994). The accumulation of NO 3 − is most obvious in leafy vegetables such as lettuce, spinach, celery, and Pak-choi.…”