Nitrates (sodium and potassium nitrate) and nitrites (sodium and potassium nitrite) are commonly used as food additives for their antimicrobial effects, and their ability to maintain certain properties. Concerns about the contribution of these additives to the formation of nitrosamines which have been linked to colorectal cancer prompted a recent change in EU legislation. To inform an up-to-date understanding of the safety of these additives, the FSA commissioned RSM UK to conduct a rapid evidence assessment of relevant literature published between 2016 and 2024. The focus of the review was human health. Due to time and resource constraints and the reasonable availability of human data through epidemiological and in vitro models, animal studies, although identified in the literature search, were not included in the review. Results showed that dietary nitrates and nitrites are rapidly absorbed, nitrates are metabolised into nitrite, nitric oxide and N-nitroso compounds, and largely excreted in urine. Oral bacteria drive nitrate to nitrite conversion, influencing systemic nitrite exposure and nitrosation, and in the acidic environment of the stomach lead to the formation of N-nitroso compounds. There was inconclusive evidence for a relationship between the intake of these additives and health risks such as cancer. The review highlighted higher cooking temperatures, longer cooking times and curing with nitrite salts are associated with increased levels of nitrosamines and N-nitroso compounds. Studies consistently showed that plant-based foods contributed significantly to dietary nitrate intake, but processed meats are a major contributor to dietary nitrite intake, sometimes leading to consumers exceeding acceptable daily limits. The review explored alternatives to nitrate and nitrite food additives, with certain beneficial properties. However, inconsistencies in the testing methodologies and risks of these alternatives were noted. Future research should focus on elucidating the precise mechanisms by which different cooking methods and additives influence the formation of nitrosamines.
Kaur et al. (Wed,) studied this question.