Nitrate in vegetables Scientific Opinion of the Panel on Contaminants in the Food chain
Nitrate in vegetables Scientific Opinion of the Panel on Contaminants in the Food chain
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DOI：
10.2903/j.efsa.2008.689
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发表时间：
2008-06-01
期刊：
影响因子：
3.3
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中科院分区：
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硝酸盐是一种天然存在的化合物，是氮循环的一部分，也是一种经批准的食品添加剂。它在植物的营养和功能中起着重要的作用。硝酸盐是蔬菜的重要组成部分，由于其积累的潜力;这可能会受到许多生物和非生物因素的影响。较高水平的硝酸盐往往存在于叶子中，而较低水平的硝酸盐存在于种子或块茎中。因此，叶类作物如莴苣和菠菜通常具有较高的硝酸盐浓度。人类接触硝酸盐主要是通过食用蔬菜，以及在较小程度上通过水和其他食物。硝酸盐也是内源性形成的。相反，其代谢产物亚硝酸盐的暴露主要来自内源性硝酸盐的转化。硝酸盐本身相对无毒，但其代谢产物和反应产物，例如，亚硝酸盐、一氧化氮和N-亚硝基化合物引起了人们的关注，因为它们可能对健康产生不利影响，如高铁血红蛋白血症和致癌作用。另一方面，最近的研究表明，亚硝酸盐参与具有抗菌活性的宿主防御，并且其他硝酸盐代谢产物如一氧化氮具有重要的生理作用，如血管调节。尽管是硝酸盐的主要来源，人们普遍认为蔬菜对健康有益，因此建议增加蔬菜的食用量。为了提供一种策略来管理食用蔬菜引起的膳食硝酸盐暴露对人类健康的任何风险，欧洲食品安全局（EFSA）食物链污染物小组（CONTAM）要求进行最新风险评估。欧盟委员会的建议。欧洲食品安全局（EFSA）的意见是，考虑到蔬菜中硝酸盐的含量，以及风险和效益之间可能的平衡。作为对要求提供蔬菜中硝酸盐含量数据的回应，EFSA收到了来自20个成员国和挪威的41，969份分析结果。不同蔬菜中硝酸盐的中位浓度差异很大，从低至1 mg/kg（豌豆和布鲁塞尔芽菜）到高至4，800 mg/kg（甘蓝）。据报告，所有样品中低于硝酸盐检测限（LOD）的不到5%。欧洲蔬菜消费量的合理近似值是根据GEMS/食品消费群膳食数据库和欧盟成员国提交的消费数据估计的。因此，使用了世界卫生组织（WHO）建议的400 g/人/天的蔬菜和水果摄入量的基础病例，但认为全部为蔬菜形式。此外，根据收集到的数据，对各种消费模式与相关食品类别中硝酸盐浓度相结合的不同情景进行了估计。这些情景表明，导致硝酸盐高膳食暴露的关键因素不是食用蔬菜的绝对数量，而是蔬菜的类型（例如叶菜）和与生产条件相关的硝酸盐浓度。硝酸盐的每日允许摄入量（ADI）为3.7 mg/kg b.w./ 2002年，前食品科学委员会（SCF）确定了一个60公斤的成年人每天摄入222毫克硝酸盐，并由粮农组织/世卫组织食品添加剂联合专家委员会（JECFA）再次确认。为评估不同蔬菜摄入量情景对健康的任何潜在影响，CONTAM小组将硝酸盐接触估计数与硝酸盐的每日允许摄入量（60公斤人每日222毫克）进行了比较。此外，为了将这些发现置于背景下，还考虑了其他硝酸盐来源的暴露，如饮用水和腌肉，平均每天35 - 44毫克/人。作为一个保守的基本情况，一个人吃400克混合蔬菜在典型的中位数硝酸盐浓度水平将收到平均膳食暴露于硝酸盐157毫克/天。即使考虑到其他饮食来源的硝酸盐暴露，这也在ADI范围内。考虑到对大多数人来说，水果的硝酸盐含量低，约为10 mg/kg，占每日400 g蔬菜和水果总推荐摄入量的一半，大多数欧盟人口的实际硝酸盐摄入量将减少到81 - 106 mg/天。硝酸盐摄入量的进一步减少可能是由于加工，例如洗涤，去皮和/或烹饪。在一些成员国，一小部分人口（2.5%）只吃叶菜，而且吃的量很大，这可能导致超过ADI。如果蔬菜是在不利的生长条件下生产的，ADI可能会超过大约两倍。专家组还指出，在不考虑任何其他硝酸盐暴露来源的情况下，在硝酸盐浓度中位数下食用超过47克的灯芯草将导致ADI以上的波动。流行病学研究并不表明从饮食或饮用水中摄入硝酸盐与癌症风险增加有关。高亚硝酸盐摄入量可能与癌症风险增加有关的证据尚不明确。专家组比较了接触蔬菜中硝酸盐的风险和益处。总体而言，估计从蔬菜中摄入的硝酸盐不太可能导致明显的健康风险，因此，食用蔬菜的公认有益效果占主导地位。专家小组认识到，偶尔会出现一些情况，例如，当地/家庭生产蔬菜的条件不利，而蔬菜构成了饮食的很大一部分，或者个人的饮食中含有大量蔬菜，如rucola，这需要逐案评估。
Nitrate is a naturally occurring compound that is part of the nitrogen cycle, as well as an approved food additive. It plays an important role in the nutrition and function of plants. Nitrate is an important component of vegetables due to its potential for accumulation; this can be affected by a number of biotic and abiotic factors. Higher levels of nitrate tend to be found in leaves whereas lower levels occur in seeds or tubers. Thus leaf crops such as lettuce and spinach generally have higher nitrate concentrations. Human exposure to nitrate is mainly exogenous through the consumption of vegetables, and to a lesser extent water and other foods. Nitrate is also formed endogenously. In contrast exposure to its metabolite nitrite is mainly from endogenous nitrate conversion.Nitrate per se is relatively non-toxic, but its metabolites and reaction products e.g., nitrite, nitric oxide and N-nitroso compounds, have raised concern because of implications for adverse health effects such as methaemoglobinaemia and carcinogenesis. On the other hand recent research indicates that nitrite participates in host defence having antimicrobial activity, and other nitrate metabolites e.g. nitric oxide, have important physiological roles such as vasoregulation. Despite being a major source of nitrate, increased consumption of vegetables is widely recommended because of their generally agreed beneficial effects for health.In order to provide a strategy to manage any risks to human health from dietary nitrate exposure resulting from vegetable consumption an updated risk assessment was requested from the Panel on Contaminants in the Food Chain (CONTAM) of the European Food Safety Authority (EFSA) by the European Commission. The opinion was to take into account the amounts of nitrate found in vegetables as consumed and any relevant considerations on the possible balance between risks and benefits.As a response to a call for data on nitrate levels in vegetables, EFSA received 41,969 analytical results from 20 Member States and Norway. There was a large variation in median concentrations of nitrate in different vegetables from a low of 1 mg/kg (peas and Brussels sprouts) to a high of 4,800 mg/kg (rucola). Less than 5% of all samples were reported as being below the limit of detection (LOD) for nitrate. A reasonable approximation of European vegetable consumption was estimated from the GEMS/Food Consumption Cluster Diets database and consumption data submitted by EU Member States. In consequence, a base case of vegetable and fruit intake of 400 g/person/day, as recommended by the World Health Organization (WHO), was used, but considered to be all in the form of vegetables. In addition, from the data collected, different scenarios combining a range of consumption patterns with concentration of nitrates in the relevant food category were estimated. The scenarios demonstrated that the critical driver for a high dietary exposure to nitrate is not the absolute amount of vegetables consumed but the type of vegetable (e.g. leafy vegetables) and the concentration of nitrate related to the conditions of production.An Acceptable Daily Intake (ADI) for nitrate of 3.7 mg/kg b.w./day, equivalent to 222 mg nitrate per day for a 60 kg adult was established by the former Scientific Committee on Food (SCF) and was reconfirmed by the Joint FAO/WHO Expert Committee on Food Additives (JECFA) in 2002. The CONTAM Panel noted that no new data were identified that would require a revision of the ADI.To assess any potential health impacts from the different vegetable intake scenarios the CONTAM Panel compared the nitrate exposure estimates with the ADI for nitrate of 222 mg/day for a 60 kg human. Additionally, to place these findings in context, exposures from other nitrate sources such as drinking water and cured meat, at an average of 35-44 mg/person per day, were also taken into account. As a conservative base case, a person eating 400 g of mixed vegetables at typical median nitrate concentration levels would on average receive a dietary exposure to nitrate of 157 mg/day. This is within the ADI even when the exposure to nitrate from other dietary sources is considered. Considering that for most people, fruit, which has low nitrate levels in the order of 10 mg/kg, comprises up to one half of the total recommended daily intake of 400 g of vegetables and fruit, actual nitrate intakes would be reduced to between 81-106 mg/day for the majority of the EU population. Further mitigation of nitrate intake may result from processing e.g. washing, peeling and/or cooking.A small part of the population (2.5%) in some Member States eats only leafy vegetables and in high amounts, which can lead to the ADI being exceeded. Should the vegetables be produced under unfavourable growing conditions the ADI could be exceeded by approximately two fold. The Panel also noted that consumption of more than 47 g of rucola at the median nitrate concentration would lead to an excursion above the ADI without taking into account any other source of nitrate exposure.Epidemiological studies do not suggest that nitrate intake from diet or drinking water is associated with increased cancer risk. Evidence that high intake of nitrite might be associated with increased cancer risk is equivocal.The Panel compared the risk and benefits of exposure to nitrate from vegetables. Overall, the estimated exposures to nitrate from vegetables are unlikely to result in appreciable health risks, therefore the recognised beneficial effects of consumption of vegetables prevail. The Panel recognised that there are occasional circumstances e.g. unfavourable local/home production conditions for vegetables which constitute a large part of the diet, or individuals with a diet high in vegetables such as rucola which need to be assessed on a case by case basis.