Scientific opinion about the risk from nitrates in vegetables

Nitrates are the compounds that occur in nature as part of the nitrogen cycle, in the soil-plant-atmosphere system and play important role in the nutrition and functioning of plants. Nitrates are naturally converted into nitrites and vice versa. Nitrogen which enters in the soil by application of fertilizers participate in many biological processes and may be assimilated by microorganisms, creating a form of nutrients available to the plants after the organic substances mineralization process. High levels of nitrate in the soil are in the correlation with their higher content in the leaves of green plants and in seeds and tubers the content is lower. Furthermore, nitrates and nitrites are easily soluble in water, mobile in the environment and can be found in waterways and therefore in drinking water. As food additives, nitrates and nitrites are widely used in the meat industry to improve quality, durability and safety of the product, in particular inhibit the bacterial growth and reproduction.
Nitrates themselves have relatively low toxicity to the human body, but their metabolites and reaction products (eg. nitrosamines) in the digestive tract can pose health concerns. Intake of nitrate in humans usually occurs through digestive tract by eating fruits, vegetables, meat and drinking water. According to the European Food Safety Authority - EFSA (2008) vegetables and fruits contribution in daily intake of nitrates range between 11 % to 41 %. Although the vegetables are one of the main sources of nitrates, because of theirs proven health benefits, intake of various vegetables are highly recommended. The World Health Organization - WHO (2003b) recommended daily intake of vegetables and fruits of 400 g splitted into several servings. On the EU level, maximum levels (ML) of nitrates in vegetables are laid down in Commission Regulation (EC) No. 1881/2006 and 1258/2011 for fresh, processed and deep frozen spinach, fresh lettuce (Lactuca sativa L.), lettuce varieties "Iceberg", rucola, processed cereal-based foods and foods for infants and young children.
Croatian Food Agency (CFA) during 2012 and 2013, conducted a survey in four Croatian cities (Zagreb, Osijek, Rijeka, Split) on the presence of nitrates in various types of vegetables whose MLs are prescribed by regulations (spinach, lettuce, rucola), but also in those types which don’t have regulated MLs (kale, chard, cabbage, broccoli, celery, horseradish, kohlrabi). There were no samples with content of nitrates above the maximum levels. In order to assess the risk of nitrates from different types of vegetables in the market and in relation to their acceptable daily intake (Eng. Acceptable Daily Intake, ADI) from 0 to 3,7 mg/kg body weight, for all results an assessment of exposure was conducted. To calculate the exposure assessment, a computer model "Improrisk" (Improvast, 2016) was used. The model combined data from unpublished CFA’s study on dietary habits of the population in Croatia and data for occurrence of nitrates obtained by this survey. Exposure assessment determined that although the value of nitrates did not exceed the legally prescribed maximum level, 0,4% of Croatian consumers exceed toxicological limits (ADI).
Consumption of vegetables included in this research is the foundation of the diet that provides optimum intake of calories, vitamins, minerals and fluids, and the optimal ratio of protein, carbohydrates and fats in human body. Satisfying the needs of the human body in relationship to building, energy and protective substances, in this case, has a higher value than the harmful effects of nitrates.