8 common food additives linked to high blood pressure and heart disease

The research, led by Dr. Mathilde Touvier, a distinguished research director at INSERM (the French National Institute for Health and Medical Research), and Anaïs Hasenböhler, a PhD student, both affiliated with the Nutritional Epidemiology Research Team at Université Sorbonne Paris Nord and Université Paris Cité, France, represents one of the most comprehensive human studies to date on this topic. Their findings contribute significantly to a growing body of evidence suggesting that the convenience offered by processed foods might come at an unforeseen cost to cardiovascular health.

Food preservatives are integral to the vast majority of industrially produced foods, serving multiple critical functions. They are primarily added to prevent the proliferation of harmful bacteria, yeasts, and molds, thereby safeguarding against foodborne illnesses and extending shelf life. Beyond microbial control, preservatives also play a crucial role in maintaining the sensory qualities of food products, preventing undesirable changes in color, flavor, and texture that can occur due to oxidation or enzymatic reactions. This multi-faceted utility has made them indispensable to the global food industry, facilitating widespread distribution, reducing food waste, and ensuring consumer access to a diverse array of products. However, despite their widespread use and regulatory approval, the long-term impact of chronic exposure to these chemical compounds on human health has remained a subject of intense scientific inquiry, particularly given the unprecedented levels of processed food consumption in contemporary societies.

Ms. Hasenböhler articulated the core motivation behind the study: "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." This statement underscores the critical gap in human epidemiological data that this research sought to address, moving beyond laboratory observations to assess real-world dietary patterns and health outcomes.

Tracking Diet and Heart Health in More Than 112,000 People: The NutriNet-Santé Cohort

The work was meticulously conducted as part of NutriNet-Santé, a large, ongoing, web-based prospective cohort study initiated in France in 2009. This ambitious research project is specifically designed to examine the intricate connections between nutrition and health within the general French adult population. The analysis for this particular study included an impressive cohort of 112,395 volunteers, all residing across France, providing a robust and geographically diverse sample size.

One of the significant strengths of the NutriNet-Santé study lies in its unusually detailed and rigorous method of dietary assessment. Rather than relying on less precise methods such as broad food frequency questionnaires, participants were asked to record everything they ate and drank during a three-day period, repeated every six months. This intensive data collection strategy provided researchers with an exceptionally granular and dynamic understanding of individual dietary habits over time. Such detailed information is crucial for accurately capturing the intake of specific food additives, which are often present in small quantities across numerous food items. The research team then undertook the painstaking task of examining the ingredients lists of all reported foods and beverages, meticulously identifying and quantifying the preservatives they contained.

Participants were subsequently followed for an average duration of seven to eight years. During this follow-up period, researchers diligently tracked the incidence of new-onset high blood pressure (hypertension) and a range of cardiovascular diseases (CVD), including serious events such as heart attack (myocardial infarction), stroke, and angina. This longitudinal design allowed for the observation of associations between dietary exposure to preservatives and the development of these chronic health conditions over a meaningful timeframe.

The sheer pervasiveness of food preservatives in modern diets was starkly evident in the baseline data: during the first two years of participation, an astonishing 99.5% of the volunteers consumed at least one food preservative. This near-universal exposure highlights the profound reach of these additives into the daily diets of the population and underscores the urgency of understanding their potential health impacts.

Higher Preservative Intake Linked to Higher Risk

The study’s findings revealed compelling and statistically significant associations, particularly among individuals with the highest levels of preservative consumption. The strongest links emerged when analyzing the intake of ‘non-antioxidant’ preservatives. Participants who consumed the largest amounts of these preservatives exhibited a 29% higher risk of developing hypertension compared to those consuming the lowest amounts. Furthermore, this group also faced a 16% higher risk of cardiovascular disease, a category encompassing severe events like heart attack, stroke, and angina.

Similarly, the analysis of ‘antioxidant’ preservatives also yielded concerning results. Individuals with the greatest intake of antioxidant preservatives were found to have a 22% higher risk of hypertension.

These two categories of preservatives function through distinct mechanisms to protect food. Non-antioxidant preservatives primarily target the prevention of microbial growth, including potentially harmful bacteria and molds, which are common causes of food spoilage and foodborne illness. Examples include nitrites, sorbates, and benzoates. In contrast, antioxidant preservatives work by slowing down oxidation, a chemical process that can lead to undesirable changes in food quality such as browning, the development of off-flavors, or rancidity, particularly in fats and oils. Common antioxidant preservatives include ascorbic acid, tocopherols, and sulfites. The distinct findings for each category suggest that the biological mechanisms linking these additives to cardiovascular health may vary.

Eight Common Preservatives Stood Out

Beyond broad categories, the researchers delved deeper, analyzing the specific effects of 17 of the preservatives most commonly consumed by the study participants. This detailed examination pinpointed eight particular preservatives that were specifically associated with a higher risk of high blood pressure:

1. Potassium sorbate (E202): A widely used antimicrobial agent found in cheese, yogurt, baked goods, and fruit products.
2. Potassium metabisulphite (E224): An antioxidant and antimicrobial agent commonly used in wine, dried fruit, and some processed potato products.
3. Sodium nitrite (E250): Predominantly used in cured meats like bacon, ham, and sausages, primarily for color fixation, flavor development, and prevention of Clostridium botulinum growth.
4. Ascorbic acid (E300): More commonly known as Vitamin C, it’s used as an antioxidant to prevent browning in fruits and vegetables and to improve dough in baked goods.
5. Sodium ascorbate (E301): The sodium salt of ascorbic acid, serving similar antioxidant functions.
6. Sodium erythorbate (E316): An isomer of sodium ascorbate, also used as an antioxidant and curing accelerator in meats.
7. Citric acid (E330): A natural acidulant and antioxidant found in many foods, from soft drinks to processed cheese.
8. Extracts of rosemary (E392): Natural antioxidants increasingly used in foods to delay lipid oxidation.

Remarkably, ascorbic acid (E300), despite its reputation as a beneficial vitamin, was also specifically associated with an increased risk of cardiovascular disease in this study. This particular finding warrants further investigation, as it suggests that the effects of compounds, even those considered healthful in other contexts, can be complex when used as food additives, possibly due to dose, form, or interactions within the food matrix.

Interpreting the Findings: Associations vs. Causation

It is crucial to emphasize that this research, being observational in nature, identifies statistical associations rather than proving direct causation. This means that while there is a clear link between higher preservative intake and increased risk of hypertension and CVD, the study cannot definitively state that the preservatives cause these conditions. There could be other confounding factors or lifestyle choices associated with high preservative intake that contribute to the observed risks.

However, the robustness of the NutriNet-Santé methodology, with its detailed dietary records and large cohort, significantly strengthens the credibility of these associations. Dr. Touvier acknowledged these inherent limitations while underscoring the study’s rigor: "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." These adjustments included accounting for factors such as age, sex, education level, family history of cardiovascular disease, smoking status, physical activity levels, and overall dietary quality (e.g., intake of fruits, vegetables, and whole grains). By controlling for these variables, the researchers aimed to isolate the independent effect of preservative intake as much as possible.

Dr. Touvier further highlighted the consistency of these human findings with existing preclinical research: "Experimental research in the literature consistently suggested that preservatives may cause oxidative stress in the body or affect the way the pancreas works." This convergence of evidence from both human epidemiology and experimental biology lends considerable weight to the hypothesis that food preservatives may indeed exert detrimental effects on cardiovascular health.

Why Preservatives Might Affect the Body: Unpacking the Mechanisms

The potential mechanisms through which food preservatives could contribute to hypertension and cardiovascular disease are complex and multifaceted. The research team is actively exploring several key pathways:

1. Oxidative Stress: This is a leading candidate. Oxidative stress occurs when there is an imbalance between the production of reactive oxygen species (free radicals) and the body’s ability to detoxify them through antioxidant defenses. These free radicals can damage cellular components, including DNA, proteins, and lipids. In the context of cardiovascular health, oxidative stress is known to contribute to endothelial dysfunction (damage to the inner lining of blood vessels), inflammation, and the development of atherosclerosis (hardening of the arteries), all of which are fundamental processes in the development of hypertension and CVD. Preservatives might either directly generate free radicals or impair the body’s natural antioxidant defenses.

2. Influence on Pancreatic Function: The pancreas plays a pivotal role in metabolic regulation, primarily through its production of insulin, a hormone essential for controlling blood sugar levels. Impaired pancreatic function can lead to insulin resistance, a condition where the body’s cells do not respond effectively to insulin. Insulin resistance is a central feature of metabolic syndrome, which significantly increases the risk of type 2 diabetes, hypertension, and cardiovascular disease. Some preservatives might directly affect pancreatic beta-cell function, leading to dysregulation of glucose and lipid metabolism, which in turn could contribute to increased blood pressure and adverse cardiovascular outcomes.

3. Inflammation: Chronic low-grade inflammation is now recognized as a key driver in the pathogenesis of numerous chronic diseases, including hypertension and atherosclerosis. Certain food additives might trigger inflammatory responses in the body, contributing to systemic inflammation that damages blood vessels and impairs organ function over time.

4. Metabolic Profile of the Blood: This refers to the levels of various metabolites (e.g., glucose, lipids, amino acids) circulating in the blood. Changes in these profiles can indicate metabolic disturbances. Preservatives could alter metabolic pathways, leading to unfavorable changes in blood lipids (e.g., increased LDL cholesterol, triglycerides) or glucose metabolism, thereby elevating cardiovascular risk.

5. Gut Microbiota Dysbiosis: The gut microbiota, the enormous and diverse community of bacteria and other microorganisms residing in the digestive tract, is increasingly recognized for its profound influence on human health, including metabolism, immune function, and cardiovascular health. A healthy gut microbiota contributes to nutrient absorption, synthesis of vitamins, and protection against pathogens. However, an imbalance (dysbiosis) in the gut microbiota, potentially induced by certain food additives, can lead to increased gut permeability ("leaky gut"), systemic inflammation, and the production of metabolites that negatively impact blood pressure and cardiovascular function. Preservatives, designed to inhibit microbial growth, could inadvertently disrupt the delicate balance of beneficial gut bacteria.

The team’s ongoing research is now actively investigating how food additives and ultra-processed foods (which are often rich in such additives) may influence these complex biological pathways. By examining the impact on inflammation, oxidative stress, the metabolic profile of the blood, and the gut microbiota, researchers hope to construct a more complete picture of why exposure to certain additives may be associated with a higher risk of disease and whether the preservatives themselves are directly contributing to these effects.

Implications for Public Health and Regulatory Action

The findings from the NutriNet-Santé study carry significant implications for public health and regulatory bodies worldwide. Dr. Touvier’s call for a re-evaluation is a powerful message: "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."

Current regulatory frameworks, such as those overseen by the European Food Safety Authority (EFSA) and the U.S. Food and Drug Administration (FDA), typically assess the safety of food additives based on acceptable daily intake (ADI) levels derived from toxicology studies, often in animal models. These assessments usually focus on individual additives and acute toxicity. However, the NutriNet-Santé study highlights the need to consider the cumulative effects of chronic, long-term exposure to multiple additives, as well as their interactions within the complex matrix of processed foods. The ADI might not adequately account for these real-world dietary patterns and potential subtle, long-term physiological disturbances.

In the interim, before any potential regulatory changes are implemented, these findings strongly reinforce existing public health recommendations. Dr. Touvier advises: "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 shift towards consuming fewer ultra-processed foods (UPFs) and prioritizing whole, unprocessed ingredients like fresh fruits, vegetables, whole grains, and lean proteins is a consistent message from nutrition experts. UPFs are typically characterized by being industrially formulated, ready-to-eat or heat, and containing numerous additives (including preservatives, artificial flavors, colors, and emulsifiers), as well as high levels of sugar, salt, and unhealthy fats, while being low in fiber and essential micronutrients. Preservatives are just one component of the "cocktail" of ingredients in UPFs that may contribute to adverse health outcomes.

The global burden of hypertension and cardiovascular disease is immense, representing leading causes of morbidity and mortality worldwide. Understanding and mitigating dietary risk factors is paramount. This study provides a compelling impetus for both consumers to make more informed food choices and for policymakers to critically reassess the long-term safety of food additives in the context of modern dietary patterns. As scientific understanding evolves, the balance between food safety, convenience, and optimal human health must be continuously re-evaluated.