Do ultra-processed foods increase heart attack risk?

Ultra-processed foods (UPFs) are never far from the headlines and you may have noticed reports linking them with an increased risk of having a heart attack or stroke. But how reliable are these claims?

These latest news stories have been sparked by a study published in JACC: Advances.

The United States study investigated the effects of eating UPFs, like crisps, fried chicken and ice cream, on the long-term likelihood of having a cardiovascular event such as a heart attack or stroke.

The researchers found the more UPFs people ate, the greater their risk of having a cardiovascular event.

Eating more than 9 servings a day was linked to a 67 per cent increased risk compared to having just 1 serving per day.

Overall, the findings back up what we already know about the link between UPFs and cardiovascular disease (CVD).

But unlike most previous studies, this study included people of different ethnicities.

It found that UPFs consumption had a stronger effect on CVD risk in Black Americans than in other racial or ethnic groups. 

What are ultra-processed foods?

UPFs are foods that have ingredients not typically found in a home kitchen, such as emulsifiers, preservatives and artificial flavours.

Many come in packages or would be considered convenience foods. Examples include:

• processed meats like ham and sausages
• fried chicken
• pizza
• mass-produced bread
• breakfast cereals
• instant soups
• crisps
• biscuits
• ice cream
• fruit-flavoured yogurts
• sugary drinks. 

What did the researchers investigate?

Earlier studies carried out in Europe and the US had shown a link between eating UPFs and developing CVD.

But they had not looked closely at the link in people of different ethnicities, sex or with varying life circumstances (socio-economic status).

So the researchers led by the University of Texas used data from a research project called the Multi-Ethnic Study of Atherosclerosis (MESA) to investigate these factors.

Their study included 6,814 US adults aged between 45 and 84 years, who did not have CVD when they joined the research project.

The sample included 39 per cent White participants, 12 per cent Chinese, 27 per cent Black, and 22 per cent Hispanic.

They all filled in a survey which asked how often they ate 120 different foods, of which 36 were UPFs including: sausages, cereals, muffins, fried chicken, sugary drinks and pizza.

And how much they ate each time – either small, medium or large servings. 

The researchers then sorted the participants into groups depending on how many UPFs they consumed.

They then compared those who ate the most to those that ate the least per day:

• 9.3 servings daily – this group ate the most
• 1.14 servings daily – this group ate the least.

And looked at how many participants had a major cardiovascular event – died from coronary heart disease or stroke or had a non-fatal heart attack or stroke – over a period of more than 15 years.

The study found people who ate more than 9 servings of UPFs per day on average were 67 per cent more likely to have a major cardiovascular event compared with people who ate 1 serving per day.

Each extra daily serving was linked with a 5.1 per cent increased risk of having an event.

Black participants had the highest percentage of UPFs in their diet, when compared with White, Chinese and Hispanic people.

And the researchers found the link between eating UPFs and cardiovascular events was particularly strong in Black Americans.

They had a 6.1 per cent increase in risk with every extra UPFs serving, compared with a 3.2 per cent increased risk among non-Black participants.

Almost a third of participants had an annual family income of less than $25,000 (£18,875) and approximately half were women.

But sex or income levels seemed to have no effect on the link between UPFs and CVD.

• Read more about ultra-processed foods and how they're categorised.

What do the researchers say?

The study supports previous research findings that diets higher in UPFs are linked to a greater risk of having a cardiovascular event, but it also shows how this link differs across ethnicities.

Researchers say food companies often target Black and Hispanic customers with marketing for unhealthy products, like sweets and sugary drinks, which might partly explain why UPFs appear to have a greater effect on CVD risk in Black Americans.

This targeted marketing is on top of the existing health inequalities that disproportionately affect Black Americans.

The researchers stress they do not know how UPFs might influence cardiovascular health.

But they suggest it's likely to be a combination of factors, including the irresistible makeup of UPFs (hyper-palatability) that encourage people to eat extra calories, which can lead to obesity.

They found those who ate more UPFs in this study also tended to eat more overall calories and had higher waist-to-height ratios (which can be a sign of carrying more fat around the abdomen).

How good is the research?

This is thought to be the first study to look at UPFs and cardiovascular risk in a large group of people from different ethnicities.

However, this was an observational study, so researchers could not say that eating UPFs caused cardiovascular events, only that the two were linked.

In addition, the study relied on people giving details about their own diets, and it's possible they could have underestimated or not accurately remembered how many UPFs they were eating.

How good was the media coverage?

The Sun and The Independent covered the story, with both explaining the study clearly with the correct findings.

But the reports did not highlight differences in the US's population mix and dietary practices with the UK's, which might mean the findings are not relatable.

For instance, the US has different dietary guidelines to recommendations in the UK.

The reports also failed to mention several of the study’s limitations, including that participants could have unintentionally under-reported what they ate.

The BHF’s verdict

This study on UPFs and cardiovascular health adds to a growing body of research suggesting diets high in UPFs are linked with a range of negative health effects, including weight gain.

These findings reflect a recent European Society of Cardiology consensus statement, which highlights UPFs as a global public health concern and urges cardiologists to discuss intake with patients.

Currently, we do not have enough research to know whether there is something specific within UPFs which is causing these issues, such as food additives.

Or whether the processing of the food itself alters the way our bodies respond to it (compared to fresh foods).

We do know that UPFs are often high in salt, sugar and saturated fat so it’s best to limit the amount you eat.

A good place to start is cutting back on foods like cakes, biscuits and ready‑made snacks, and cooking more meals from scratch – steps we already know can help improve diet quality and support better heart health.

If in doubt, turn to the NHS Eatwell Guide for an evidence-based approach to eating a healthy diet. 

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