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A study published in The BMJ looks at food additive preservatives and cancer risk.
Comments from the Science Media Centre Ireland:
Professor William Gallagher, School of Biomolecular and Biomedical Science, University College Dublin, comments:
“This is a large-scale observational study, which means there were no specific interventions, where dietary patterns were tracked over 24 hour periods, and then subsequent cancer incidence tracked in a long-term view (up to 14 years). Importantly, one cannot make causal links directly from this study, but it does make some interesting observations particularly in respect to an association between higher intake of non-antioxidant preservatives and higher rates of overall cancer, breast and prostate cancer. These higher rates of cancer are modest (e.g. 10-30% increased risk) but are significant when taken at a population-based level in terms of potential impact.
“From my perspective, the work stands out as it did not particularly focus on ultra-processed foods, but took a broader view of dietary intake of food additives, using brand-specific information rather than a generalised assessment. Indeed, only about a third of the additive preservatives examined in this study were from ultra-processed foods.
“Of interest, while a substantial number of study participants took part (>100,000), nearly 80% of them were women, tended to be older and ate less processed meat. This suggests a slight bias to the study, but it looks like they tried their best to control for this.
“This work is unique in its scale of assessment of food additives in a large number of study participants, and also puts added focus on the recognition by the International Agency for Research on Cancer (IARC) that food additive nitrites and nitrates are probably carcinogenic.
“The challenge for a lot of these studies is the lack of direct causal link, although there are some other, separate studies which have examined the direct impact of these sort of additives on tumour behaviour in model systems (cell cultures from humans and animal models).
“I believe the study to be an important piece of work, which is challenging to do, especially at this scale and over the time duration studied. It has potentially important public health implications.”
Declarations of interest: I don’t have any relevant conflict of interests. For full disclosure, I am part time Chief Scientific Officer of OncoAssure, a molecular diagnostics company. I don’t have any links with the food industry.
Professor Mark Lawlor, Professor of Digital Health, Queen’s University Belfast and Academic Lead of the Peace Plus Digital ONEHEALTH Hub, comments:
“Increasingly, we are recognising that a OneHealth approach, embracing not just the health of the individual but also the health of the food that we eat, the water that we drink and the air that we breathe, is critical to ensuring our collective health and wellbeing. This current study, a detailed analysis on a cohort of over 105,000 individuals, shows the importance of balancing the use of food preservatives to extend shelf life with the risk of a number of these food additives contributing to the development of cancer.
“Some of the increased risks observed by the researchers give cause for concern, for example potassium sorbate was associated with a 26% increased risk of developing breast cancer, while sodium nitrite was associated with a 32% increased risk of prostate cancer development. These data highlight the importance of pursuing a holistic OneHealth approach and ensuring that regulatory agencies consider both the negative and the positive effects of food additives when making decisions on the food that we eat.”
Declarations of interest: “no relevant declarations of interest”
Dr Gavin Stewart, Reader in Interdisciplinary Evidence Synthesis, Evidence Synthesis group, Newcastle University, said:
“The authors highlight the uncertainty associated with analysis of observational data appropriately. The conclusion that calls for future re-evaluation of the safety of these food additives considering the balance between benefit and risk for food preservation is warranted. However, any calls for changes in consumer behaviour would be premature given the uncertainty surrounding analysis of multiple subgroups and the potential for false-positive errors. Even if future evidence can confidently demonstrate health benefits of avoiding preserved food, that may still be outweighed by the costs for some consumers.”
Prof Tom Sanders, Professor emeritus of Nutrition and Dietetics, King’s College London, said:
“This latest publication from France shows an association between some food additives and risk of cancer. The participants who consumed most of these additives differed in several respects from those with low intakes: they consumed more processed meat, sugar, and salt, and less fruit and vegetables, and more women were taking oral contraceptives. Although the investigators tried to adjust for these differences in their statistical analysis, the marginally higher risk (13 percent) of cancer at age 60 could be due to an inability to completely correct for other factors already known to contribute to risk as suggested in the accompanying editorial. It is already well established that processed meat products are associated with increased risk of cancer. Alcohol intake is strongly linked to risk of cancer and the association with sulphite intake noted may simply be an association between wine consumption and risk (sodium metabisulphite is used to kill yeast in winemaking).
“It is worth stressing that the additives most strongly related to risk were nitrites/nitrates which are used to cure ham and bacon and also some types of sausages (in the UK most sausages no longer use nitrites, the exception being frankfurters). Bacon can also be produced without nitrites but it is more expensive. Both industrially produced ham as well as traditionally made ham contain nitrates/nitrite. Salt petre (potassium nitrate) has been used for centuries to produce ham: it preserves the meat by reacting with haemoglobin and myoglobin causing the meat to be pink and prevents the growth of the deadly bacteria Clostridium botulinum. The nitrate is converted to nitrite on curing but it also leads to the formation of nitrosamines and nitrosamides which are proven carcinogens. Banning the use of nitrates/nitrites would make these ham products unavailable. An alternative would be to label foods that use nitrates/nitrites with a health warning.”
Rachel Richardson, Methods Support Unit Manager, The Cochrane Collaboration, said:
“As observational studies go, this has many strengths, including a large sample and robust methods for assessing peoples’ diets and quantifying their exposure to various food preservatives over time. The authors acknowledge that the sample is not necessarily representative of the general population, being mostly made up of women (78.7%) with healthier than average lifestyles. It is also likely that the people who contribute to the database used have a greater than average interest in food and health, which again means that this may not be a representative sample.
“As with all observational studies, there is the risk of confounding when a factor influences both the exposure and the outcome. The authors of the editorial accompanying this article highlight a potential confounder: the correlation between preservatives and their food vectors. For example, people who consumed sulphites did this predominantly through alcoholic beverages. However, there are other potentially carcinogenic compounds in alcohol, for example acetaldehyde.
“It is important to set the headline of the press release in context: a higher intake of SOME food preservatives is linked to increased cancer risk. Further down the press release it is stated that, ‘of the 17 individually studied preservatives, 11 were not associated with cancer incidence, and no link was found between total preservatives and cancer incidence’.
“It’s also worth pointing out that the associations found were generally modest and the margins of error mean that the true effect could be very small. For example, the increased risk of any cancer with a higher consumption of acetic acid was 12%, but at the lower limit of the confidence interval, the estimate would be 1% (in technical terms the hazard ratio was 1.12, but the 95% confidence interval stretched from 1.01 to 1.25). Of course, even a difference of 1% could be significant at a population level.
“In summary, this study will make an important contribution to research in this field, but will need to be taken in context and assessed alongside other work.”
Prof Gunter Kuhnle, Professor of Nutrition and Food Science, University of Reading, said:
“This is a study that investigates the potential health effects of food preservatives, but the data used in this study is not sufficient to do so.
“In order to be able to investigate the health effects of preservatives, it is crucial to know how much preservatives individual study participants consume. Unfortunately, this information is not available.
“Manufacturers are not required to provide detailed food composition data to researchers, and the use of preservatives – and other additives – changes constantly depending on the quality of raw products, consumer preferences and other factors.
“NutriNet-Santé has published several papers investigating the health effects of additives, but detailed methodological data are not easily available. A small number of foods has been analysed for some additives, but information on which foods and which additives have been included in these analyses are difficult to find. Moreover, several additives also occur naturally and it is difficult to distinguish between naturally occurring and added compounds.
“The unreliability of the data is highlighted by the results which disagree with most other data: for example the adverse health effect of nitrite is well established and higher intake results in a higher disease risk. However, the current study suggests that only moderate – but not high – intake is associated with higher risk of cancer.
“Similarly, in this study moderate intake of ascorbic acid – more commonly known as Vitamin C – is associated with higher cancer risk, but not low or high intake.
“In the UK and the EU, all permitted food additives are regularly reviewed for their impact on health. Regulators such as the UK’s Food Standard Agency (FSA) or the European Food Safety Authority (EFSA) review toxicological and other scientific data to ensure that potential risks are identified. While some members of the public might be concerned about the safety of food additives following this study, in my view the study does not contain any data that justify such concerns.”
‘Intake of food additive preservatives and incidence of cancer: results from the NutriNet-Santé prospective cohort’ by Anaïs Hasenböhler et al. was published in the BMJ at 23:30 UK time on Wednesday 7 January 2026.
DOI: 10.1136/bmj-2025-084917
Declared interests
Dr Gavin Stewart: “I have no conflicts of interest to declare.”
Prof Tom Sanders: “I was Chair of the British Nutrition Foundation Report on Nutrition and Development: Short and Long term consequences for Health.
I have received grant funding for research on vegans in the past. I have been retired for 10 years but during my career at King’s College London, I formerly acted as consultant for companies that made artificial sweeteners and sugar substitutes.
I am a member of the Programme Advisory Committee of the Malaysia Palm Oil Board which involves the review of research projects proposed by the Malaysia government.
I also used to be a member of the Scientific Advisory Committee of the Global Dairy Platform up until 2015.
I did do some consultancy work on GRAS affirmation of high oleic palm oil for Archer Daniel Midland more than ten years ago.
My research group received oils and fats free of charge from Unilever and Archer Daniel Midland for our Food Standards Agency Research.
I was a member of the FAO/WHO Joint Expert Committee that recommended that trans fatty acids be removed from the human food chain.
Member of the Science Committee British Nutrition Foundation. Honorary Nutritional Director HEART UK.
Before my retirement from King’s College London in 2014, I acted as a consultant to many companies and organisations involved in the manufacture of what are now designated ultraprocessed foods.
I used to be a consultant to the Breakfast Cereals Advisory Board of the Food and Drink Federation.
I used to be a consultant for aspartame more than a decade ago.
When I was doing research at King’ College London, the following applied: Tom does not hold any grants or have any consultancies with companies involved in the production or marketing of sugar-sweetened drinks. In reference to previous funding to Tom’s institution: £4.5 million was donated to King’s College London by Tate & Lyle in 2006; this funding finished in 2011. This money was given to the College and was in recognition of the discovery of the artificial sweetener sucralose by Prof Hough at the Queen Elizabeth College (QEC), which merged with King’s College London. The Tate & Lyle grant paid for the Clinical Research Centre at St Thomas’ that is run by the Guy’s & St Thomas’ Trust, it was not used to fund research on sugar. Tate & Lyle sold their sugar interests to American Sugar so the brand Tate & Lyle still exists but it is no longer linked to the company Tate & Lyle PLC, which gave the money to King’s College London in 2006.”
Rachel Richardson: “I have no interests to declare.”
Prof Gunter Kuhnle:
“• Current funding: BBSRC Transforming UK Food System (FoodSEqual);