A team in France worked with more than 44,000 people in a study running from 2009 called NutriNet-Santé. The Guardian reports they looked at how much of their diet – and calories – was made up of “ultra-processed” foods – those made in factories with industrial ingredients and additives, such as dried ready meals, cakes and biscuits.
Over seven years of follow-up, there were 602 deaths, of which 219 were from cancer and 34 from cardiovascular disease. The report says they found that deaths were more likely to occur in those who ate more ultra-processed food. The link was clear even after taking into account the greater likelihood of deprivation, smoking, obesity and lower educational background among those who ate ultra-processed food, the researchers say.
Ultra-processed foods tend to be high in sugar, salt and saturated fat. France consumes less of such packaged foods and ready meals than many other countries, at around 14% of the diet. More than half the UK diet is ultra-processed food.
Other scientists were unsure whether the study proved a link between ultra-processed food and an early death, but, the report says, agreed it was more evidence that a junk food diet was bad for health. “The case against highly processed foods is mounting up, with this study adding importantly to a growing body of evidence on the health harms of ultra-processed foods,” said Professor Nita Forouhi, of the MRC Epidemiology Unit at the University of Cambridge. She said more evidence was needed, “yet we would ignore these findings at public health’s peril”.
“A vital takeaway message is that consumption of highly processed foods reflects social inequalities – they are consumed disproportionately more by individuals with lower incomes or education levels, or those living alone,” Forouhi said in the report. “Such foods are attractive because they tend to be cheaper, are highly palatable due to high sugar, salt and saturated fat content, are widely available, highly marketed, ready to eat, and their use-by dates are lengthy, so they last longer. More needs to be done to address these inequalities.”
Other scientists said it was difficult to draw firm conclusions from the study, partly because the “ultra-processed” foods category was so large, ranging from packet soups to chocolate bars.
“This is a large, carefully conducted prospective study of healthy middle-aged and older French people, in which a statistically significant association between death from any cause and a relatively higher consumption of ‘ultra-processed foods’ has been identified,” said Dr Ian Johnson, nutrition researcher and emeritus fellow at the Quadram Institute Bioscience in the report.
“To put things into perspective, although the risk of dying over the seven-year period of investigation was about 15% higher among those consuming more of these foods, the background risk across the whole group was low.”
Importance: Growing evidence indicates that higher intake of ultraprocessed foods is associated with higher incidence of noncommunicable diseases. However, to date, the association between ultraprocessed foods consumption and mortality risk has never been investigated.
Objective: To assess the association between ultraprocessed foods consumption and all-cause mortality risk.
Design, Setting, and Participants: This observational prospective cohort study selected adults, 45 years or older, from the French NutriNet-Santé Study, an ongoing cohort study that launched on May 11, 2009, and performed a follow-up through December 15, 2017 (a median of 7.1 years). Participants were selected if they completed at least 1 set of 3 web-based 24-hour dietary records during their first 2 years of follow-up. Self-reported data were collected at baseline, including sociodemographic, lifestyle, physical activity, weight and height, and anthropometrics.
Exposures: The ultraprocessed foods group (from the NOVA food classification system), characterized as ready-to-eat or -heat formulations made mostly from ingredients usually combined with additives. Proportion (in weight) of ultraprocessed foods in the diet was computed for each participant.
Main Outcomes and Measures: The association between proportion of ultraprocessed foods and overall mortality was the main outcome. Mean dietary intakes from all of the 24-hour dietary records available during the first 2 years of follow-up were calculated and considered as the baseline usual food-and-drink intakes. Mortality was assessed using CépiDC, the French national registry of specific mortality causes. Hazard ratios (HRs) and 95% CIs were determined for all-cause mortality, using multivariable Cox proportional hazards regression models, with age as the underlying time metric.
Results: A total of 44 551 participants were included, of whom 32 549 (73.1%) were women, with a mean (SD) age at baseline of 56.7 (7.5) years. Ultraprocessed foods accounted for a mean (SD) proportion of 14.4% (7.6%) of the weight of total food consumed, corresponding to a mean (SD) proportion of 29.1% (10.9%) of total energy intake. Ultraprocessed foods consumption was associated with younger age (45-64 years, mean [SE] proportion of food in weight, 14.50% [0.04%]; P < .001), lower income (<€1200/mo, 15.58% [0.11%]; P < .001), lower educational level (no diploma or primary school, 15.50% [0.16%]; P < .001), living alone (15.02% [0.07%]; P < .001), higher body mass index (calculated as weight in kilograms divided by height in meters squared; ≥30, 15.98% [0.11%]; P < .001), and lower physical activity level (15.56% [0.08%]; P < .001). A total of 602 deaths (1.4%) occurred during follow-up. After adjustment for a range of confounding factors, an increase in the proportion of ultraprocessed foods consumed was associated with a higher risk of all-cause mortality (HR per 10% increment, 1.14; 95% CI, 1.04-1.27; P = .008).
Conclusions and Relevance: An increase in ultraprocessed foods consumption appears to be associated with an overall higher mortality risk among this adult population; further prospective studies are needed to confirm these findings and to disentangle the various mechanisms by which ultraprocessed foods may affect health.
Laure Schnabel; Emmanuelle Kesse-Guyot; Benjamin Allès; Mathilde Touvier; Bernard Srour; Serge Hercberg; Camille Buscai; Chantal Julia