Nearly everyone eats them: These 8 food preservatives may be tied to high blood pressure, large French study finds

Almost no one avoids food preservatives. In a new French study, 99.5% of participants consumed at least one of them during their first two years of tracking. That near-universal exposure is why researchers wanted to know what they might be doing to the cardiovascular system over time. Their answer, published in the European Heart Journal, is a warning, though not a verdict.

The study was observational. It found statistical associations between preservative intake and health outcomes, but it cannot prove the additives caused them. Eating one of these ingredients does not mean you will develop high blood pressure or heart disease.

The research sits within NutriNet-Santé, a long-running French project on nutrition and health. It included 112,395 volunteers across France. Every six months, each participant logged everything they ate and drank over a three-day period, which gave the team more precise dietary data than broad consumption estimates would. Researchers then examined the ingredients in those foods and drinks, including their preservatives. They followed participants for an average of seven to eight years, watching for hypertension and for cardiovascular events such as heart attack, stroke and angina.

The work was led by Dr. Mathilde Touvier, a research director at INSERM (the French National Institute for Health and Medical Research), and Anaïs Hasenböhler, a PhD student. Both are part of the Nutritional Epidemiology Research Team at Université Sorbonne Paris Nord and Université Paris Cité.

The clearest signals came from people who ate the most of certain preservatives, compared with those who ate the least:

The two groups work differently. Non-antioxidant preservatives generally stop bacteria and mold from growing. Antioxidant preservatives slow oxidation, the chemical process that browns foods, gives them off flavors or turns them rancid.

The team looked closely at 17 of the preservatives participants consumed most often. Eight were specifically associated with a higher risk of high blood pressure:

Ascorbic acid (E300) was also specifically associated with cardiovascular disease.

One possibility is oxidative stress, which occurs when reactive molecules accumulate faster than the body's defenses can neutralise them, potentially damaging cells and tissues over time. Researchers are also looking at whether preservatives affect the pancreas, which plays a central role in regulating blood sugar and metabolism.

Hasenböhler, as quoted by Science Daily, stressed how new this line of evidence is: "Food preservatives are used in hundreds of thousands of industrially processed foods. Experimental studies suggest that some preservative food additives may be harmful to cardiovascular health, but we have not had enough evidence on the impact of these ingredients in humans. As far as we know, this is the first study of its kind to investigate the links between a wide range of preservatives and cardiovascular health."

Touvier acknowledged the design's limits while defending the data: "This study has some limitations inherent to its observational design. However, the findings are based on highly detailed data, and we have taken account of other factors that can increase or lower the risk of cardiovascular disease. Experimental research in the literature consistently suggested that preservatives may cause oxidative stress in the body or affect the way the pancreas works.

"These results suggest we need a re-evaluation of the risks and benefits of these food additives by the authorities in charge, such as the EFSA in Europe and the FDA in the USA, for better consumer protection. In the meantime, these findings support existing recommendations to favor non-processed and minimally processed foods, and avoid unnecessary additives. Doctors and other healthcare professionals play a key role in explaining these recommendations to the public."

The team is now studying how food additives and ultra-processed foods may influence inflammation, oxidative stress, the metabolic profile of the blood, and the gut microbiota, the community of bacteria and other microorganisms in the digestive tract that is increasingly studied for its links to metabolism, immune function and cardiovascular health. The goal is to understand why exposure to certain additives is associated with higher disease risk, and whether the preservatives themselves contribute to it.