Many of the foods we eat every day contain preservatives. These substances help food last longer, keep its color, and prevent the growth of bacteria or mold.
They are especially common in packaged and processed foods such as cured meats, ready-made meals, snacks, and drinks. For a long time, preservatives have been considered safe when used in approved amounts.
However, two large new studies from France suggest that regularly eating foods with certain preservatives may be linked to a slightly higher risk of developing cancer or type 2 diabetes over time.
The studies were published in two respected scientific journals, BMJ and Nature Communications. Both studies are part of a large ongoing research project that has followed the eating habits and health outcomes of more than 100,000 adults in France.
Participants regularly filled out detailed questionnaires about what they ate and drank, allowing researchers to track long-term patterns rather than short-term effects.
In the first study, published in BMJ, researchers found links between several commonly used food preservatives and higher rates of cancer. The strongest links were seen for cancers overall, as well as breast cancer and prostate cancer.
The preservatives that stood out most were nitrites and nitrates. These are chemicals often added to processed meats such as ham, bacon, sausages, and other cured meat products. They help prevent bacterial growth and give meat its familiar pink color.
The study found that people who consumed more sodium nitrite had about a one-third higher risk of developing prostate cancer compared with those who consumed less. While this increase may sound worrying, the researchers emphasized that the overall risk increase was still moderate.
For example, heavy smoking increases the risk of lung cancer more than fifteen times, which is far greater than the increase linked to preservatives. Still, even a moderate increase can matter when large numbers of people are exposed over many years.
The second study, published in Nature Communications, focused on type 2 diabetes. It also found links between certain food additives and a higher risk of developing the disease.
One preservative in particular, potassium sorbate, was associated with roughly double the risk of diabetes. Potassium sorbate is widely used to stop mold and bacteria from growing in foods such as baked goods, cheese, and drinks.
Both studies were supervised by French epidemiologist Mathilde Touvier. She stressed that eating foods with preservatives does not mean a person will suddenly develop cancer or diabetes. These diseases develop slowly and are influenced by many factors, including genetics, overall diet, physical activity, and lifestyle. However, she explained that repeated exposure over many years may increase risk, especially when combined with other unhealthy habits.
Her advice to the public was simple and practical. She encouraged people to limit how much processed food they eat and to choose less processed options when shopping. Fresh foods such as fruits, vegetables, grains, and minimally processed meats generally contain fewer additives and preservatives.
Outside experts praised the large size and careful design of the studies but also urged caution. Because these were observational studies, they cannot prove that preservatives directly cause cancer or diabetes. They can only show that people who eat more of these additives also tend to have higher rates of certain diseases. Other factors may be involved.
For example, nutrition expert Tom Sanders from King’s College London pointed out that processed meat and alcohol are already strongly linked to cancer risk.
This means that it may be difficult to fully separate the effects of preservatives from the effects of the foods and drinks that contain them. In one example, he suggested that a preservative used in wine might appear linked to cancer when the real risk comes from drinking alcohol itself.
Even so, Sanders suggested that one possible step could be clearer warning labels on foods that use nitrates or nitrites, allowing consumers to make more informed choices.
These findings come at a time when governments are paying closer attention to diet and health. Just days before the studies were published, the United Kingdom announced a ban on daytime television, radio, and online advertising for unhealthy foods high in fat, salt, and sugar. This shows growing concern about how modern diets affect long-term health.
Looking at the findings overall, these studies do not suggest panic or drastic changes. Instead, they add to a growing body of evidence that highly processed foods may carry hidden risks when eaten often and over long periods.
The results support existing public health advice to eat a balanced diet with more whole and minimally processed foods. While more research is needed to confirm these links and understand the exact role of preservatives, the studies highlight the importance of moderation, awareness, and informed food choices.
If you care about diabetes, please read studies about diabetes and vitamin B12, and the right diet for people with type 2 diabetes.
For more health information, please see recent studies about how to eat smart with diabetes, and turmeric and vitamin D: a duo for blood pressure control in diabetic patients.
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