Nitrites and Nitrates Associated With Increased Cancer Risk

Nathalie Barrès

April 19, 2022

This article was originally published in French on Univadis.

Key Takeaways

  • A French study investigated the relationship between intake of nitrites and nitrates (all sources combined) and the risk of cancer.

  • Data from more than 100,000 individuals were analyzed, with the results showing an increase of close to 25% in the risk of breast cancer among those who frequently consumed nitrate-containing products in their diet and an increase of close to 60% in the risk of prostate cancer among those who frequently consumed nitrite-containing food products.

  • No association was demonstrated with regard to exposure to natural sources of nitrites and nitrates.

Why Is This Important?

Nitrites and nitrates occur naturally in water and soils, but they are also used as preservatives in processed meats. Although the results need to be confirmed by other large-scale prospective studies, they certainly add new food for thought in the lively debate on a potential precautionary ban on the use of these additives. Various international public health authorities already recommend limiting consumption of foods containing controversial additives.


The study included adults from the ongoing NutriNet-Santé cohort, which began in 2009 (median follow-up, 6.7 years).

Exposure to nitrites and nitrates was analyzed on the basis of participants' consumption over 24 hours, which was determined using a food composition database and the trade names and brands of the industrial products in question.

Main Findings

Of the 101,056 adults enrolled, 78.5% were women, and the mean age at enrollment was 42.3 years. The mean number of 24-hour consumption records was 5.5 per individual.

In the full cohort, 3311 incident cases of cancer were diagnosed during follow-up. Compared with those who did not consume foods containing nitrates in the form of food additives, the largest consumers of these products had a 24% higher risk of developing breast cancer, particularly before menopause (hazard ratio [HR], 1.24; 95% CI, 1.03 – 1.48; P = .02), especially in the case of exposure to potassium nitrate.

The risk of prostate cancer was increased by 58% (HR, 1.58; 95% CI, 1.14 – 2.18; P = .008), particularly for sodium nitrite exposure.

The risk of developing colorectal cancer was not significantly increased by these two families of additives. The authors hypothesized that the study lacked statistical power for these latter analyses.

No association was demonstrated between consumption of nitrites or nitrates from natural sources and the development of cancer.

The authors suggest that these preservatives may lead to the formation of N-nitroso compounds, which are potentially carcinogenic substances for humans.

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