Two major studies suggest that eating many certain food preservatives could increase the risk of type 2 diabetes and some types of cancer. The research was published in the medical journals Nature Communications and The BMJ and is based on long-term health data from France. Food preservatives are chemicals added to packaged foods to help them last longer.
They are commonly found in ultra-processed foods, such as ready meals, packaged snacks, processed meats, and soft drinks. Scientists say the findings could have significant public health implications due to the widespread use of these additives. Earlier lab studies showed that some preservatives can harm cells or damage DNA. However, there is a lack of strong evidence linking them to long-term diseases in people. These new studies sought to enhance our understanding of the potential links between preservatives and adult type 2 diabetes or cancer.
The research was based on a large set of data. Scientists used diet and health records collected over many years. The information was gathered between 2009 and 2023. More than 100,000 adults participated in the study.
All participants were volunteers. They were part of the French NutriNet-Santé research program. Participants regularly reported what they ate, allowing researchers to closely track preservative intake over many years. Scientists examined preservatives both as a group and one by one. In total, 17 different preservatives were studied. In the cancer study published in The BMJ, researchers found no overall link between total preservative intake and cancer.
They also found that 11 of the 17 preservatives showed no connection to cancer. However, people who consumed higher amounts of certain preservatives had a higher risk of developing some cancers compared with those who consumed little or none. For example, people who consumed more potassium sorbate had a 14% higher risk of cancer overall and a 26% higher risk of breast cancer. Sulphites, often used in wine and processed foods, were linked to a 12% higher risk of overall cancer. Sodium nitrite, commonly found in processed meats, was linked to a 32% higher risk of prostate cancer. Potassium nitrate was associated with higher risks of both overall cancer and breast cancer. Other preservatives, such as acetates and acetic acid, were also linked to increased cancer risk. Researchers explained that some preservatives may affect the body’s immune system or increase inflammation, which could help cancer develop over time.
The second study, published in Nature Communications, focused on type 2 diabetes. It found that people with the highest intake of preservatives had a much higher risk of developing the disease. Compared with those who consumed the least, the risk was 47% higher overall. Both antioxidant and non-antioxidant preservatives showed similar increases. Individual studies linked 12 of the 17 preservatives to a higher risk of type 2 diabetes. According to the researchers, the present is the first large study to directly examine the link between preservative intake and diabetes risk in humans.
The scientists stressed that both studies were observational, meaning they show links but cannot prove cause and effect. Other unknown factors could also have influenced the results. Still, the studies were large, long-term, and based on detailed food records, and their findings match earlier laboratory research. Experts assert that the elevated risks are moderate, yet even minor increases become significant when numerous individuals come into contact with them. Professor William Gallagher from University College Dublin said that, at a population level, these risks could have a real impact on public health. The researchers called on health agencies to review current rules on food preservatives. They also urged food companies to reduce unnecessary additives and encouraged consumers to choose fresh and minimally processed foods whenever possible.
