Risk assessment of nitrate and nitrite in feed

Abstract

The European Commission asked EFSA for a scientific opinion on the risks to animal health related to nitrite and nitrate in feed. For nitrate ion, the EFSA Panel on Contaminants in the Food Chain ( CONTAM Panel) identified a BMDL 10 of 64 mg nitrate/kg body weight (bw) per day for adult cattle, based on methaemoglobin (MetHb) levels in animal's blood that would not induce clinical signs of hypoxia. The BMDL 10 is applicable to all bovines, except for pregnant cows in which reproductive effects were not clearly associated with MetHb formation. Since the data available suggested that ovines and caprines are not more sensitive than bovines, the BMDL 10 could also be applied to these species. Highest mean exposure estimates of 53 and 60 mg nitrate/kg bw per day in grass silage‐based diets for beef cattle and fattening goats, respectively, may raise a health concern for ruminants when compared with the BMDL 10 of 64 mg nitrate/kg bw per day. The concern may be higher because other forages might contain higher levels of nitrate. Highest mean exposure estimates of 2.0 mg nitrate/kg bw per day in pigs’ feeds indicate a low risk for adverse health effects, when compared with an identified no observed adverse effect level ( NOAEL ) of 410 mg nitrate/kg bw per day, although the levels of exposure might be underestimated due to the absence of data on certain key ingredients in the diets of this species. Due to the limitations of the data available, the CONTAM Panel could not characterise the health risk in species other than ruminants and pigs from nitrate and in all livestock and companion animals from nitrite. Based on a limited data set, both the transfer of nitrate and nitrite from feed to food products of animal origin and the nitrate‐ and nitrite‐mediated formation of N‐nitrosamines and their transfer into these products are likely to be negligible.

Determination of Nitrate and Nitrite in Swiss Chard (Beta vulgaris L. subsp. vulgaris) and Wild Rocket (Diplotaxis tenuifolia (L.) DC.) and Food Safety Evaluations

“…More recently, the European Food Safety Authority (EFSA) released two scientific opinions regarding nitrite/nitrate levels in food and feed and their implications for human health [ 7 , 8 ]. The undesired presence of nitrite in animal feed was also discussed by the EFSA in a scientific opinion published in 2009 [ 9 ]. This last document identified, other than the well-known methemoglobinemia concern [ 10 ], two other toxicological endpoints related to nitrite toxicity, namely the equivocal evidence for carcinogenesis in female mice and the adrenal zona glomerulosa hypertrophy in rats.…”

“…Vegetables, particularly leafy vegetables, are characterized by high nitrate concentration, so that a great part of nitrate daily intake derives from vegetable consumption [ 9 , 20 ]. This nitrate accumulation, which takes place especially in the leaves, is mainly due to the increasing use of nitrogen fertilizers in agriculture [ 21 ], with the residual levels depending on many factors, such as the plant genotype, temperature, light exposure, cultivation system [ 22 , 23 ] water relations, carbon dioxide concentration, soil type, and contemporary use of herbicides [ 24 , 25 ].…”

Impact of calcium nitrate supplementation on the oxygen-carrying capacity of lactating sows and their offspring

“…Although swine production feeding practices vary, it can be said that swine are exposed to nitrate through various feedstuffs. Conclusions from a recent comprehensive weight-of-evidence evaluation on the existing literature corroborated EFSA’s safety benchmark value for nitrate of 410 mg/kg-bw/d ( EFSA, 2020 ) in swine as protective of concerns for MetHb as well as for adversity related to vitamin A depletion, growth, and reproductive performance. Moreover, the application of the weight-of-evidence evaluation provided moderate-to-high confidence that the no-observed-adverse-effect level (NOAEL) is likely above EFSA’s value and between 674 and 870 mg/kg-bw/d (~600 to 800 mg/kg-bw/d; Doepker et al, 2021 ).…”

Saliva nitrite is higher in male children with autism spectrum disorder and positively correlated with serum nitrate

“…Nitrite and nitrate have been recognized as an endogenous reservoir of NO, but nitrate is reported to exercise its function always via conversion to nitrite [ 47 ]. Intake food or drinks has a direct impact on oral nitrate levels [ 48 ], with 60–80% dietary source from vegetables, 15–20% from drinking water and 10–15% from cured meat [ 49 ]. As for nitrite in human, exogenous dietary sources plays a minor role in endogenous nitrite levels, for oral nitrite is mainly converted by oral commensal bacteria from nitrate that is reabsorbed and concentrated in saliva glands [ 50 ].…”