Preservatives found in ‘healthy’ foods like yoghurts, bread and orange juice may increase high blood pressure and heart disease risk, study reveals

Food preservatives found in yoghurts, fruit juice, wholegrain bread and scores of other everyday products could significantly raise the risk of heart disease, research suggests. 

French scientists found people consuming the highest levels of preservatives were 16 per cent more likely to suffer heart disease, heart attacks and strokes.

They were also almost 30 per cent more likely to develop high blood pressure – the leading risk factor for stroke.

The researchers said eight of the 17 most commonly consumed preservatives appeared to directly raise blood pressure.

The study, published in the European Heart Journal, analysed the diets of nearly 112,400 people.

Anaïs Hasenböhler, of Université Paris Cité, said: ‘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.’

In the study, participants were followed for an average of seven to eight years, during which they completed a food and drink questionnaire every six months detailing what they had consumed over the previous three days. 

Almost all – 99.5 per cent – of the participants consumed at least one food preservative within the first two years of taking part, however the elevated heart risk was only seen in those who consumed the most.

The lowest consumers averaged about 156mg of preservatives a day, while the highest consumed more than 1g daily. 

The researchers did not publish detailed examples of what the highest consumers ate each day. 

However, they reported that the highest consumers ate far more ultra-processed food overall, with such products making up 21.4 per cent of their diet by weight, compared with 14.3 per cent among the lowest consumers.

They said the biggest sources of preservatives included processed meats, packaged breads and cereals, processed fruit and vegetables, alcoholic drinks and other packaged foods and drinks. 

The increased heart risk seemed to be driven by eight preservatives including potassium sorbate, potassium metabisulphite, sodium nitrite and ascorbic acid.

These preservatives – added to packaged foods to extend shelf life – are found in everything from baked goods to fruit juices, processed meats and ice cream. 

While the researchers could not pinpoint exactly why these additives may increase the risk of major heart problems, they said preservatives could trigger oxidative stress – a form of cellular damage linked to inflammation, ageing and disease. 

However, because this was an observational study, no firm conclusions could be drawn about cause and effect. 

The researchers concluded: ‘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 advice to favour fresh and minimally processed foods, such as fruit, vegetables, fish, legumes and fibre-rich foods, to help prevent high blood pressure and heart disease,’ the researchers said.

They added that doctors and healthcare professionals had an important role in helping the public understand the risks.

Independent experts welcomed the study but urged caution over its findings, stressing that it cannot prove preservatives directly caused heart disease.

Rachel Richardson, an expert in public health research who was not involved in the study, said people consuming more preservatives may also have had generally less healthy lifestyles.

‘The reason they experience more ill-health may be due to this, rather than the preservatives themselves,’ she said.

However, she added that the researchers had adjusted for major factors including age, BMI, smoking, physical activity and overall diet, meaning the findings ‘warrant further investigation’.

Richardson also noted the study was conducted in France and mainly involved women with healthier lifestyles than the general population, meaning the results may not fully apply to the UK.

Other experts said preservatives still play an important role in keeping food safe, extending shelf life and helping keep costs down.

In the UK, food additives are regularly reviewed by regulators and substances deemed unsafe can be removed from the market.

Professor Gunter Kuhnle, of the University of Reading, said research into additives was important, but warned studies must carefully separate the effects of preservatives from broader dietary habits that might be damaging to health.

High blood pressure affects around 14 million adults in the UK and is the leading cause of heart attacks and strokes.

Often dubbed a ‘silent killer’, the condition frequently causes no symptoms, meaning many sufferers are unaware they have it until serious complications develop.