The comments come after two major studies published in the BMJ found links between the regular consumption of processed foods such as ready meals and an increased risk of heart attacks, stroke and dying young.
Professor Julian Cooper, chair of the Institute of Food Science and Technology Scientific Committee described the reference to ‘ultra-processed foods’ as very unclear and confusing and “deemed by many experts to require further research due to significant limitations”.
The studies
The first study of 105,159 French adults found that for every 10% rise in the proportion of ultra-processed food eaten, a person’s risk of cardiovascular disease, coronary heart disease and conditions affecting blood supply to the heart and the brain rose by 12%, 13% and 11% respectively.
Separate research on 19,899 Spanish university students, who were also tracked for ten years, discovered that higher consumption of ultra-processed foods – more than four servings per day – was associated with a 62% higher chance of dying compared to eating fewer than two servings a day.
The researchers said further studies were needed to better understand these effects and concluded a direct link remained to be established, but called for policies that promote consumption of fresh or minimally processed foods.
Studies’ limitations
“It’s important to remember that observational studies like these can only show an association,” Victoria Taylor, senior dietitian at the British Heart Foundation, said.
“They cannot tell us what is behind this. The classification of ultra-processed foods used by the researchers is very broad, so there could be a number of reasons why these foods are being linked to increased risk to our health, for example nutritional content, additives in food or other factors in a person’s life. Before we consider making any changes to advice or policy it is important to understand this thoroughly.”
Dr Gunter Kuhnle, associate professor in nutrition and health, at the University of Reading, described the focus on “ultra-processed foods” as the one “major limitation” of the studies.
‘Neither specific nor useful’
“While the term is convenient to create the image of ‘unhealthy food’, it is neither specific nor useful to inform public health or give dietary advice,” he said.
Dr Kuhnle added that ultra-processed food was commonly assumed to be food that is extensively processed.
He cited preservatives, stabilisers, emulsifiers, solvents, binders, bulkers; sweeteners, sensory enhancers, colours and flavours; processing aids and other additives as examples.
But he also pointed out food which undergoes few processing steps, such as hamburgers, crisps or chips, or contains preservatives that have been used for centuries such as preserves, falls under this remit.
Inconsistencies
“It is also not obvious why salami is considered to be ultra-processed, yet cheese, which often requires considerably more processing steps and additives, is not,” Dr Kuhnle continued. “The classification combines a wide range of foods with very different potential impacts on health, which limits its usefulness as a basis for recommendations.”
Previous studies have linked ultra-processed foods to higher risks of obesity, high blood pressure, high cholesterol, and some cancers, but firm evidence is still scarce.
Professor Mark Lawrence of the Institute for Physical Activity and Nutrition at the Deakin University in Australia said future research priorities should explore associations between ultra-processed food and health harms in different populations around the world.
‘Shift emphasis away from reformulation’
“Policy makers should shift their priorities away from food reformulation—which risks positioning ultra-processed food as a solution to dietary problems—towards a greater emphasis on promoting the availability, affordability, and accessibility of unprocessed or minimally processed foods,” he wrote in a linked editorial to the BMJ research.
Professor Cooper added that snacks, desserts and some meats, prepared by food manufacturers, enabled consumers to have convenient, safe and shelf stable choices, which are packaged for protection during distribution.
“Approved food additives perform a wide variety of functions in foods, for example preservatives, acidity regulators and antioxidants which keep food in a good condition, thus reducing waste, whilst preserving the nutritional quality,” he said. “Colours, sweeteners, emulsifiers and stabilisers contribute to the product quality and improve the eating experience. We look forward to hearing Professor Mike Gibney’s views on the subject at the IFST Annual Lecture on 2 July.”
