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 linked to 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 is steadily decreasing, 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 connected to cancer risk that you can play a role in changing, including smoking, drinking alcohol, physical activity and diet.
Regarding diet, there is no single miracle food against cancer. It is important to consider your whole diet. We know that there is a connection between high consumption of ultra-processed food and cancer (as well as cardiometabolic diseases, such as heart disease and diabetes).
The reasons for this connection can be varied, but French researchers are moving on preservatives and their relationship with the risk of cancer, since they tend to be common in ultra-processed foods. They published their findings in the BMJ. Let’s break down what they found.
How Was This Study Done?
The researchers drew data from the French NutriNet-Santé cohort for the years 2009 to 2023; this study was designed to investigate the 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.
At enrollment and every six months, participants completed a series of three validated web-based 24-hour dietary records. In each period, dietary records were randomly assigned to three non-consecutive days over two weeks (two weekdays and one weekend day). Making days non-consecutive and including one weekend day helps provide a more accurate picture of his overall diet.
The researchers took the information from the dietary records of the participants and distributed the consumption 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 especially on preservatives. They then quantified participants’ consumption of both naturally occurring 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 physician committee validated each reported cancer event against official medical records. In addition, the NutriNet-Santé cohort was linked 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 31 December 2023; the only cancer not included was basal cell carcinoma of the skin.
What Did This Study Find?
The average follow-up time for the participants was almost eight years. This study found multiple associations between preservatives that are widely used in industrial food and beverages in both the American and European markets and higher incidences of general, breast and prostate cancer. In particular, these preservatives have been linked to a higher risk of cancer:
Most of the 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 is important to remember that because this study is observational, it can only draw connections—or associations—which does not mean causation. More research is needed to confirm these findings. Limitations of this study include self-reporting of participants’ food intake, which may introduce bias. The researchers also note that it was difficult to estimate some of the naturally occurring preservatives in some foods.
How Does This Apply to Real Life?
The preservatives analyzed in this study are currently categorized by the US Food & 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 be changed, however, as in the cases of Red No. 3 dye and brominated vegetable oil. Unfortunately, it can take years of research and evidence to finally ban an additive, and in the meantime, it 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 are 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 help 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 reducing the consumption of processed and red meat and avoiding alcohol.
There always seems to be a caveat with any recommendation, however. For example, with a higher consumption of produce can come a higher consumption of herbicides and pesticides, which can also increase the risk of cancer. This is not a reason, however, 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 cost of buying organic just isn’t feasible, that’s OK—try to wash your produce thoroughly before cooking or eating, and if you’re still concerned, remove the peel after washing.
While there is no single anti-cancer diet, a Mediterranean diet style of eating 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.
Take our expert
This study linked several commonly used preservatives to a higher risk of cancer. To lower your risk, stick to more whole foods, including fruits, vegetables, whole grains, legumes, nuts, seeds and lean proteins. The Mediterranean diet has got you covered, and has also been linked to a lower risk of other diseases, including heart disease and diabetes. However, this does not mean that you have to give up processed food altogether. If you are concerned, read the label closely and check to see if a product contains preservatives associated with cancer. Other lifestyle changes that can reduce your cancer risk include avoiding smoking and alcohol and engaging in regular physical activity.
Read the original article on EatingWell