These foods are guilty of increasing the risk of obesity, high blood pressure, high cholesterol and some types of cancer.
Two large European studies published by 'BMJ' find positive associations between consumption of highly processed ('ultraprocessed') foods and the risk of cardiovascular disease and death. Researchers say more work is needed to better understand these effects, and a direct (causal) link has not yet been established, but they require policies that promote consumption of fresh or minimally processed foods rather than highly processed foods.
Ultra-processed foods include baked goods and packaged snacks, soft drinks, sweetened cereals, prepared foods containing food additives, dehydrated vegetable soups, and reconstituted meat and fish products, which often contain high levels of added sugar, fat and/or salt, but lack vitamins and fibre. They are believed to account for about 25-60 percent of daily energy intake in many countries. Previous studies have linked ultraprocessed foods, which are blamed for increasing all-cause mortality, to increased risks of obesity, high blood pressure, high cholesterol and some cancers, but firm evidence is still scarce.
In the first of these new studies, researchers based in France and Brazil assessed possible associations between ultraprocessed foods and the risk of cardiovascular and cerebrovascular disease (conditions that affect the blood supply to the heart and brain). Their findings are based on 105,159 French adults (21 percent men and 79 percent women), with an average age of 43, who completed an average of six 24-hour dietary questionnaires to measure regular intake of 3,300 different foods as part of the 'NutriNet.-Santé' study. Foods were grouped according to degree of processing and disease rates were measured during a maximum follow-up of 10 years (2009-2018). The results showed that a 10 percent absolute increase in the proportion of ultraprocessed foods in the diet was associated with significantly higher rates of overall cardiovascular disease, coronary heart disease and cerebrovascular disease (12 percent, 13 percent and 11 percent increase, respectively). In contrast, the scientists found a significant relationship between minimally processed or unprocessed foods and the lowest risks of all reported diseases.
60% higher risk from all causes
In the second study, researchers from the Department of Preventive Medicine and Public Health of the University of Navarra evaluated the possible associations between the intake of ultraprocessed food and the risk of death from any cause ("all-cause mortality"). Their findings are based on 19,899 Spanish university graduates (7,786 men and 12,113 women) with an average age of 38 who completed a 136-item dietary questionnaire as part of the University of Navarra (SUN) Follow-up Study. Again, foods were grouped according to degree of processing and deaths were measured over an average of 10 years.
The results showed that higher consumption of ultraprocessed foods (more than 4 servings per day) was associated with a 62 percent higher risk of all-cause mortality compared to lower consumption (less than two servings per day). For each additional daily serving of ultraprocessed food, the mortality risk increased by a relative 18 percent (a dose-response effect). Both studies are observational, so they cannot establish causality, and there is a possibility that some of the observed risks may be due to unmeasured confounding factors. However, both papers took into account known lifestyle risk factors and dietary quality markers, and the findings support other research linking highly processed foods to poor health. As such, both research teams say policies that limit the proportion of ultraprocessed foods in the diet and promote consumption of unprocessed or minimally processed foods are needed to improve global public health. This view is supported by Australian scientists in a related editorial, who say the dietary advice is relatively simple: eat less ultraprocessed foods and more unprocessed or minimally processed foods.
They say that future research should explore the relationships between ultraprocessed foods and health damage in different populations around the world, and examine how the damage occurs (for example, by changing the intestinal microbiome in ways that could disrupt the energy balance). Meanwhile, they believe that policymakers "should shift their priorities from food reformulation, which risks positioning ultraprocessed foods as a solution to dietary problems, to a greater emphasis on promoting the availability, affordability and accessibility of unprocessed or minimally processed foods.