Unsurprisingly, ultra-processed foods are bad for us. However, two comprehensive studies on the effects of these types of foods have found positive associations between their consumption and risk of cardiovascular disease and death.
The two large European studies were published in the BMJ.
What are the main findings?
While there is no conclusive evidence that ultra-processed foods lead to a higher risk of high blood pressure, cholesterol, obesity, and some cancers, several studies have found strong causal links. These new studies add to an already large, growing literature.
The first study, carried out by scientists in France and Brazil, specifically analyzed the potential associations between ultra-processed foods and heart and brain conditions. 105,159 French adults, with an average age of 43, were tested. They completed, on average, six daily dietary questionnaires to have their intake of different types of foods measured.
Foods were grouped according to how processed they were, while rates of disease were then followed for ten years of the subjects' lives (from 2009-2018).
The research showed that as little as a 10% increase in the proportion of ultra-processed foods was associated with more than 10% increases in the risk of cardiovascular disease, coronary heart disease, and cerebrovascular disease. Meanwhile, those who ate more unprocessed foods had a significantly lower risk of all of these diseases.
The second study, carried out in Spain, saw researchers study possible associations between the eating of ultra-processed foods and risk of death from any cause ("all cause mortality").
19,899 Spanish university graduates were studied, with an average age of 38. They completed a 136-item dietary questionnaire. Again, foods were grouped according to how processed they were. Deaths were measured over a ten year period.
Similarly, those who consumed more than 4 servings per day of ultra-processed foods led to as much as a 62% increase in mortality.
What is an ultra-processed food?
Processed foods have typically been altered to make them taste better or have a longer shelf life, usually by adding salt, oil, fermentation or sugar.
Ultra-processed foods, however, have been through lengthy industrial processing and typically have long ingredient lists on the packaging, with added preservatives, color enhancers, sweeteners, and other chemical additives. Examples include fizzy drinks, mass-produced bread, ready meals, sausages, and hamburgers.
Both studies are observational meaning they can't establish a conclusive causality. There is a possibility that some of the observations may be due to unmeasured confounding factors.
Despite this, the researchers have rightly stated that both studies add to a growing number of studies finding a strong causality between consumption of these foods and major health risks. They have called for policymakers to promote the availability, accessibility, and affordability of unprocessed foods.