Health effects of nitrates and nitrites, a review

In this presentation the acceptable daily intake (ADI) of nitrate is discussed together with the effects of nitrate and nitrite as found in toxicological studies. The toxicity of nitrate per se is low but in humans 5-10 % of nitrate is converted into the more toxic nitrite by salivary or gastrointestinal reduction. The toxic effects of nitrite are methaemoglobinaemia and fall of blood pressure. Nitrite - induced hypertrophy of the adrenal zona glomerulosa is considered as a physiological adaptation to repeated episodes of low blood pressure and not as a toxic effect. There is no evidence that nitrite is carcinogenic. It is concluded that the current recommendations for nitrate intake pose no threat for human health. Incidental intake exceeding the ADI causes negligible risk. However, high nitrate intake for a prolonged period should be avoided.