Reviewed by Dietitian Madeline Peck, RDN, CDN
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Key points
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Food preservatives can be natural or synthetic and extend the shelf life of food.
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Some common preservatives have been associated with an increased risk of cancer.
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Focusing on whole foods when possible can reduce the risk of cancer.
While the risk of dying from cancer has steadily declined, cancer rates continue to rise, with more than 2 million new cases expected to be diagnosed in 2026. Many factors can increase your risk of cancer, including genetics. And while genetics is out of your control, there are several lifestyle areas related to cancer risk that you can play a role in changing, including smoking, alcohol consumption, physical activity, and diet.
When it comes to nutrition, there is no such thing as a miracle anti-cancer food. It’s important to consider your entire diet. We know there is a link between high consumption of ultra-processed foods and cancer (as well as cardiometabolic diseases such as heart disease and diabetes).
The reasons for this connection may be varied, but the French researchers are focusing on preservatives and their relationship to cancer risk, as they tend to be common in ultra-processed foods. They published their findings in BMJ. Let’s break down what they found.
How was this study conducted?
The researchers extracted data from the French NutriNet-Santé cohort for the years 2009 to 2023; this study was designed to investigate associations between nutrition and health. There were more than 105,000 participants, almost 80% of them women, with an average age at baseline of 42 years.
At enrollment and every six months, participants completed a series of three web-validated 24-hour food records. At each period, dietary records were randomly assigned to three non-consecutive days over two weeks (two weekdays and one weekend day). Doing non-consecutive days and including a weekend day helps provide a more accurate picture of your overall diet.
The researchers took information from the participants’ dietary records and broke down their intake of nutrients, including vitamins C and E, which can be used as preservatives in some foods. In addition, using brand-specific data, the researchers also broke down food additives, focusing in particular on preservatives. They then quantified participants’ intake of both natural preservatives (including acetic and citric acids, nitrites, nitrates and sulfites) and added preservatives. In total, 58 preservatives were investigated.
Participants reported any health-related incidents, including cancer diagnoses, during the study period, either in their biannual health questionnaires or at any time through their connected health portal. To ensure the accuracy of participant reporting, an expert committee of physicians validated each reported cancer event against official medical records. In addition, the NutriNet-Santé cohort was connected to the database of the national health insurance system to collect additional information on medical treatments and consultations.
The cohort was also linked to the French national mortality registry to identify deaths and causes of death. For this study, incident cancer included all primary cancers diagnosed between study enrollment and December 31, 2023; the only cancer not included was basal cell carcinoma of the skin.
What did this study find?
The average follow-up time for participants was nearly eight years. This study found multiple associations between preservatives that are widely used in industrial foods and beverages in both the US and European markets and higher incidences of overall, breast and prostate cancer. In particular, these preservatives have been linked to a higher risk of cancer:
The most associations were observed for non-antioxidant preservatives. Among the antioxidant preservatives, only total erythorbates and specific sodium erythorbate were found to be associated with a higher incidence of cancer. It’s important to remember that because this study is observational, it can only establish connections — or associations — which does not mean causation. More research needs to be done to confirm these findings. Limitations of this study include participants’ self-reporting of dietary intake, which may introduce bias. The researchers also note that it was difficult to estimate some of the natural preservatives in some foods.
How does this apply in real life?
The preservatives that were analyzed in this study are currently classified by the US Food and Drug Administration as generally recognized as safe (GRAS). This means that to date, the FDA does not have enough evidence to ban them. This can change, however, as with the Red dye no. 3 and brominated vegetable oil. Unfortunately, it can take years of research and evidence to finally ban an additive, and in the meantime, they can affect your health.
Preservatives are often found in foods such as alcoholic beverages, processed meats, refined grains, processed fruits and vegetables, and breakfast cereals. Anything that is shelf stable will likely contain preservatives.
If you’re trying to reduce your cancer risk, the American Cancer Society recommends being physically active, limiting sedentary time, and reaching and maintaining a healthy weight to reduce your cancer risk. They suggest eating more plants, including fruits, vegetables, legumes, and whole grains, and less sugar-sweetened beverages, highly processed foods, and refined grains — which also means aiming for less added sugar overall. They also recommend cutting back on processed and red meat and avoiding alcohol.
However, it seems there is always a caveat with any recommendation. For example, with higher produce intake may come higher consumption of herbicides and pesticides, which may also increase the risk of cancer. However, this is not a reason to avoid fruits and vegetables. Instead, you can buy organic produce, especially the fruits and vegetables on the Environmental Working Group’s Dirty Dozen List. If the expense of buying organic isn’t feasible, that’s okay—try to wash your produce well before cooking or eating it, and if you’re still concerned, remove the peel after washing.
Although there is no such thing as an anti-cancer diet, a Mediterranean diet covers all the bases recommended by the American Cancer Society. If you’re new to this way of eating and want to give it a try, try our 5-Day Mediterranean Diet Meal Plan for Beginners. For those of you further along in your journey, try our 30-day sugar-free Mediterranean diet meal plan.
Our expert
This study linked several commonly used preservatives to a higher risk of cancer. To lower your risk, stick mostly to whole foods, including fruits, vegetables, whole grains, legumes, nuts, seeds, and lean protein. The Mediterranean diet has you covered and has also been associated with a lower risk of other diseases, including heart disease and diabetes. However, that doesn’t mean you have to give up processed foods completely. If you’re concerned, read the label carefully and look to see if a product contains preservatives linked to cancer. Other lifestyle changes that can reduce your risk of cancer include avoiding smoking and alcohol and engaging in regular physical activity.
Read the original article on EatingWell