- A new study involving more than 100,000 participants concludes that certain food preservatives could harm cardiovascular health.
- The researchers identify eight preservatives that are linked to hypertension (high blood pressure).
- They also concluded that one additive was specifically associated with cardiovascular disease.
- While worrying, the study design means that the results cannot conclusively prove causation.
The results of a recent study published in the European Heart Journal suggest that certain common preservatives in food may increase hypertension and cardiovascular risk
Because this observational study cannot prove causation — other factors may explain the link — the authors call for further research
They also call for a re-evaluation of the risks by the relevant bodies, including the Food and Drug Administration (FDA) and the European Food Safety Authority (EFSA)
The rise of preservatives in food
With ultra-processed foods (UPFs) making headlines on a weekly basis, the scientific community and public at large are more focused on the potential health effects of food additives than ever before
Preservatives, as the name suggests, prevent food from spoiling and pathogen invasion. They both improve food safety while increasing profits by extending shelf life. In 2019, roughly one-third of products purchased in the United States contained at least one preservative
To be used in a product in the U.S., the United Kingdom, Europe, and many other regions, these additives are tested for safety. However, some believe that this testing is not thorough enough
Interestingly, certain preservatives naturally occur in foods, such as ascorbic acid (vitamin C) and alpha-tocopherol (vitamin E). Consumption of these compounds within whole foods is associated with better cardiovascular health
However, some early research suggests that their impact may be harmful
when consumed outside of whole foods, at least for some populations
According to the authors of the new study, little research has been conducted on the cardiovascular effects of preservatives, so this study provides fresh insights
Some preservatives linked to type 2 diabetes, cancer
The current study uses data from the largest nutrition study of its kind, called NutriNet-Santé
The project began in France in 2009 and now involves more than 100,000 participants who regularly submit dietary data. The researchers also have access to blood samples and stool samples to assess participants’ gut microbiome
In recent years, the group has focused on the impact of ultra-processed foods and additives on health. Earlier this year, for instance, they published research looking at the links between preservatives, type 2 diabetes, and cancer
They concluded that preservative intake was associated with an increased incidence of type 2 diabetes and some cancers. Now, they are focusing on the association between these additives, hypertension, and cardiovascular disease
Quick note: In this study, the statistical term “incidence” measures the number of new cases of hypertension or cardiovascular disease that occurred during the study’s follow-up
Which preservatives are most common in food?
In total, the analysis included data from 112,395 people, more than two-thirds of whom were female, with an average age of 42.8. These individuals were followed for an average of 7.9 years
The scientists identified 58 different preservatives that were consumed by participants. Of these, 17 were consumed by at least 10% of participants, so the researchers focused on these compounds and their associations with cardiovascular disease and hypertension
The most common 10 preservatives were:
- Citric acid:Consumed by 91.3% consumers (largely from processed fruit and vegetables).
- Lecithins:86.4%.
- Total sulphites:83.5% (mostly from alcoholic drinks).
- Ascorbic acid:83.0% (largely from processed fruit and vegetables).
- Sodium nitrite:73.3% (largely from processed meat products).
- Potassium sorbate: 65.3%.
- Sodium erythorbate: 52.5% (largely from processed meat products).
- Sodium ascorbate: 49.7%.
- Potassium metabisulfite: 44.2%.
- Potassium nitrate: 32.3% (largely from processed meat products).
Unearthing new links between preservatives and heart health
As part of their analysis, the scientists accounted for a range of variables, including age, sex, height, body mass index (BMI), physical activity, smoking status, educational level, and family history of cardiometabolic disorder and hypertension
Their analysis also controlled for macronutrient consumption, how much fruit and vegetables they ate, and their intake of alcohol, salt, meat products, and dairy
Even after adjusting for these factors, they found that higher intakes of total non-antioxidant preservatives were associated with a higher incidence of cardiovascular disease and coronary heart disease
Similarly, higher intakes of these preservative types were associated with a higher incidence of hypertension:
- total preservatives:24% higher
- total non-antioxidant preservatives: 29% higher
- total antioxidant preservatives:22% higher
Antioxidant preservatives prevent chemical spoiling, whereas non-antioxidant preservatives work by killing microbes
When the scientists drilled down into specific compounds, greater intakes of these preservatives were associated with a higher incidence of hypertension:
- total sorbates:39% higher
- potassium sorbate:39% higher
- citric acid: 25% higher
- potassium metabisulfite: 16% higher
- total nitrites:16% higher
- sodium nitrite: 16% higher
- ascorbic acid: 14% higher
- sodium erythorbate: 14% higher
- total ascorbates:13% higher
- total erythorbates: 13% higher
- sodium ascorbate: 12% higher
- total sulphites: 11% higher
- extracts of rosemary: 10% higher
When assessing which individual preservatives were associated with a higher incidence of cardiovascular disease, only one remained significant:
- ascorbic acid: 15% higher
Importantly, the researchers found no statistical interaction between diet quality or intake of UPFs. This means the effect is not solely because people who consumed more preservatives had an overall poorer diet
Limitations and the future
The current study has limitations. Because it is an observational study, it cannot prove causation. It is still possible that some other factor is responsible for the relationship between preservatives and heart health
However, the authors end their paper with a call to arms: “This study provides new insights for revisiting the evaluation of the safety of these food additives, which should consider the benefit/risk balance between food preservation with these additives and their potential impact on cardiovascular health.”
As evidence mounts that food additives may cause harm, many are looking to reduce their intake
Medical News Todaycontacted Dr. Federica Amati, a research fellow at Imperial College London in the United Kingdom. Amati also works clinically as a registered nutritionist.
We asked how people could reduce their intake of preservatives. “In the U.S., [around 57%] of foods are ultraprocessed, and the majority of these products contain preservatives. It’s virtually impossible to reduce your preservative intake to zero, but cutting down on UPFs is a great place to start.”
When possible, she suggested we should prioritize whole foods, which will naturally have fewer cosmetic commercial additives. “As a double benefit,” she explained, “these foods, which include fruit, whole grains, veg, nuts, seeds, herbs, and spices, are rich in fiber.”
This is particularly important in this case, she explained, as “we know that fiber is an essential nutrient that supports good gut health, immune function, and heart health.”
“If you want to start small, focus on reducing some of the worst offenders first,” she suggested. “Processed meat products, which often contain nitrate and nitrite preservatives, are also associated with poorer health if eaten regularly, so try to replace these with unprocessed white meats when possible.”
Sodas also often contain preservatives, and like processed meat products, are associated with poorer health when consumed regularly. So, “Try to replace these with water, unsweetened tea and coffee, or fermented products like kombucha or kefir,” she told us.
“However, remember to read the labels and check for products that include live cultures and a short ingredient list — not all fermented beverages are created equal.”
