A study reports that the consumption of processed foods containing nitrites and nitrates as preservatives is associated with an increased risk of breast and prostate cancer.
Nitrite and nitrate salts are preservatives widely used by the food industry, particularly in the process of manufacturing deli meats. These molecules, in particular nitrites, inhibit the growth of harmful microorganisms such as Clostridium botulinumthe bacteria responsible for botulism, and also improve the appearance of these foods by binding to myoglobin to form the compound (nitrosohaemochrome) which is responsible for the typical pinkish tint in deli meats.
Another chemical transformation of meat caused by nitrates and nitrites is the formation of so-called N-nitroso compounds (nitrosamines, for example). These molecules, produced by the interaction of nitrite with the amino acids of meat proteins, can be generated by cooking at high temperature (bacon, for example) or in an acid environment (as in the stomach).
The formation of these compounds is problematic, as numerous studies have shown that they possess a strong affinity for DNA and cause mutations that can trigger the development of cancer.
These carcinogenic compounds would therefore play a very important role in the increase in cancers of the digestive system (esophagus, stomach, colon) frequently observed in people who consume large quantities of cold cuts. It is for this reason that deli meats are now classified as group 1 carcinogens (proven carcinogens for humans) by the International Agency for Research on Cancer.
A French study suggests that the negative impact of nitrates and nitrites is not limited to the digestive system, but could also promote the development of the two main types of cancer affecting the population, namely those of the breast and the prostate1. In this study, the researchers analyzed the dietary habits of 101,056 participants to determine the total daily intake of nitrites and nitrates and followed, for a period of 7 years, the incidence of the various cancers affecting this population.
By associating the 3311 incident cases of cancer that were diagnosed during this period with the dietary intake of nitrates and nitrites, the researchers observed a 24% increase in the risk of developing breast cancer (premenopause) in women. who regularly consumed foods rich in nitrates compared to those who consumed little or none at all.
In men, it is the consumption of foods rich in nitrites which seems particularly harmful, with a 58% increase in the risk of prostate cancer which is observed.
The carcinogenic potential of nitrites and nitrates therefore seems to be widespread, even affecting organs that are not in direct contact with these compounds following their ingestion.
It should be noted that these increases in the risk of cancer are not observed for natural sources of nitrates and nitrites (fruits and vegetables, for example), which confirms that these molecules are not carcinogenic as such and that they are rather the N-Nitroso compounds, formed by their reaction with meat proteins, which are responsible for their negative impact on health.
There are therefore only advantages to reducing the consumption of processed products containing nitrites and nitrates. Reducing the intake of industrial cold cuts and products containing cold cuts (pizzas, sandwiches) is particularly important, because these products are the main source (more than 95%) of the carcinogenic nitrites and nitrates identified in the study.
1. Chazelas E et coll. Nitrites and nitrates from food additives and natural sources and cancer risk: results from the NutriNet-Santé cohort. Int. J. Epidemiol.published on March 18, 2022.