Eating ultra-processed foods (UPFs) may be less important to your lifespan than the quality of your overall diet, according to a three-decade-long Harvard University study.
The research claims that consuming a high number of ultra-processed foods is associated with a four per cent higher risk of death from all causes. However, certain UPFs can have a more negative impact on your health than others. UPFs often include additives like colouring and flavours and are typically high in energy, sugar, fat, and salt – without the benefits of vitamins or fibre.
The worst of these, according to the study? Ready-to-eat meat, poultry and seafood products – plus fizzy drinks, dairy-based desserts, and highly processed breakfast foods (like sugary cereals). The researchers say that you don’t need to restrict all UPFs from your diet, but restricting these ones could improve your long-term health.
Do ultra-processed foods increase your risk of death?
While we know that UPFs can increase your risk of obesity, heart disease including heart attacks, and diabetes, it's been previously unclear exactly how UPFs increase your risk of death.
To find out, the research – published in The British Medical Journal – tracked the health of nearly 75,000 women and nearly 40,000 men in the USA for over 34 years. Participants were all health professionals, with no history of cancer, cardiovascular diseases or diabetes at the start of the study.
Every two years, these people reported on their health – and every four years completed a detailed diet questionnaire. The team then split the participants into four quarters depending on their UPF consumption: the lowest quarter consumed about three UPF servings per day while the highest quarter ate seven UPFs per day.
The results? Those in the top quarter had a four per cent higher risk of all deaths. There was also a nine per cent higher risk of death by specific causes, such as an eight per cent higher risk of death caused by neurodegenerative diseases (like dementia).
Crucially, the study found that the link between UPF consumption and death was weakened when they factored in overall diet. This means a higher quality of diet (for example, one containing lots of vegetables, fruits, legumes and wholegrain items) may be more important than the quantity of UPFs you eat.
Dietitian Dr Duane Mellor, who was not involved in the study, said that this appears to suggest that “it might not be as simple as that those who ate more ultra-processed foods were more likely to die earlier – it is quite possible that these foods might displace healthier foods from the diet.”
Surprisingly, the study also did not find any association between UPFs and cause-specific deaths from cardiovascular diseases, cancer, or respiratory diseases.
“The results of the study are interesting and show that high UPF intake is not always associated with higher disease risk,” said Gunter Kuhnle, professor of nutrition and food science at the University of Reading, who was also not involved in the study.
The researchers acknowledged that, as an observational study, the research does not draw firm conclusions – especially since the participant pool was predominantly white and restricted to the same profession.
Kuhnle added that “the results of this study should be treated with a lot of caution.”
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