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The burden of ultra-processed foods

New research links consumption of ultra-processed foods to 10% of premature deaths in Brazil and accelerated cognitive decline

Ultra-processed foods are high in added sugar, fat, salt, and chemical compounds

Léo Ramos Chaves / Revista Pesquisa FAPESP

Two recent studies out of Brazil have found a significant statistical association linking excessive intake of ultra-processed foods to avoidable deaths and accelerated cognitive decline among Brazilian consumers. A paper recently published in the American Journal of Preventive Medicine estimates that in 2019 alone, at least 57,000 premature deaths in Brazil were attributable to overconsumption of ultra-processed foods. Another study, published in December 2022 in JAMA Neurology, suggests that too much intake of these foods leads to a 28% faster rate of overall cognitive decline.

Ultra-processed foods—a broad category of foods that are high in added sugar, fat, salt, or chemical compounds that enhance their shelf life or palatability—are typically poor in nutritional value compared to their original ingredients. Examples include processed meats like sausages and chicken nuggets, sandwich cookies, soft drinks, snacks, ice creams, and processed sweets. Ultra-processed foods are often high in calories. An 80-gram frozen hamburger, for example, provides 25% of the recommended daily intake of fat, while a can of soda contains 12% of the maximum amount of sugar recommended in any 24-hour period.

The World Health Organization (WHO) defines premature deaths as deaths occurring between the ages of 30 and 69 that are not solely attributable to old age. Car accidents, homicides, falls, and poisoning are among the most common causes of preventable deaths, along with noncommunicable diseases like heart problems, obesity, and cancer.

Using epidemiological modeling, the researchers estimated the number of nonnatural deaths linked to the consumption of ultra-processed foods in Brazil in 2019. “Intake of ultra-processed foods was modeled as a risk factor for premature deaths, and this data was compared with estimated all-cause risk and mortality based on international scientific literature,” explains biologist Eduardo Nilson, a researcher affiliated with the Center for Epidemiological Research in Nutrition and Health at the University of São Paulo (NUPENS-USP) and the Oswaldo Cruz Foundation (FIOCRUZ) in Brasília, and the lead author of the first study.

The research team used the Brazilian Institute of Geography and Statistics’ (IBGE) 2017–2018 Family Budget Survey to determine the levels of consumption of ultra-processed foods in the country. The survey estimated that ultra-processed foods represent between 13% and 21% of Brazilians’ daily diet, depending on the age and sex of respondents. These data, combined with information from the Brazilian Ministry of Health’s DataSUS database, supported an estimate of around 57,000 premature deaths in 2019 linked to the consumption of ultra-processed foods. This represents 10.5% of all premature deaths among Brazilians during that period. If only deaths from noncommunicable diseases were considered, then processed foods would account for a significantly larger share of deaths at 21.8%.

Léo Ramos Chaves / Revista Pesquisa FAPESPThe study found a 28% faster rate of cognitive decline in adults whose diet was more than one-fifth ultra-processed foodsLéo Ramos Chaves / Revista Pesquisa FAPESP

The study, conducted in collaboration with colleagues from the Federal University of São Paulo (UNIFESP) and the Catholic University of Chile, also modeled three scenarios in which Brazilians decrease their total average calorie intake from unhealthy processed foods. A 10% reduction by weight in the consumption of these items would prevent 5,900 premature deaths, while a 20% reduction would mean 12,000 fewer deaths. A more drastic reduction of 50% in ultra-processed food consumption would result in 29,300 lives saved per year.

The researchers recommend adopting measures to discourage the consumption of ultra-processed foods. A new set of regulations issued last October require food manufacturers to implement front-of-package labeling on food products to inform consumers of any high amounts of three nutrients: added sugars, saturated fats, and sodium (see Pesquisa FAPESP issue nº 319). Large manufacturers have 12 months to comply with the new regulations, while small producers have a two-year grace period. “Other health measures include regulating the marketing of foods in school and workplace settings, introducing subsidies for the production and sale of fresh local produce, and raising taxes on ultra-processed foods,” says Nilson.

Gunter Kuhle, a nutrition and food science professor at the University of Reading in the UK, who did not participate in the study, suggests that people who consume ultra-processed foods may have other risk factors, such as smoking or a lack of exercise, which also contribute to premature deaths. “We don’t know to what extent ultra-processed foods are responsible for health problems or whether they are just one of several markers of an unhealthy lifestyle,” Kuhle said in an interview with Pesquisa FAPESP.

The second study found an association between excessive consumption of ultra-processed foods and the more subtle problem of cognitive decline. The researchers investigated whether a diet high in processed foods could accelerate the decline in mental function, especially executive function—executive function is not only critical for reasoning and problem-solving abilities, but also for regulating skills required for autonomy, such as conscious control of actions, thoughts, and emotions.

The data for the study were collected between 2008 and 2017 as part of the Brazilian Longitudinal Study on Adult Health (ELSA), with funding from FAPESP and the Brazilian Ministry of Health. The researchers analyzed data on 10,775 individuals in six Brazilian cities—Porto Alegre, Salvador, and the capitals of all southeastern states. All volunteers were active or retired university staff over 35 years of age. The average age of all participants was 50.6 years. Each volunteer was followed for an average of eight years and evaluated at three different time points.

Léo Ramos Chaves / Revista Pesquisa FAPESP

Respondents first answered a questionnaire with 114 questions about their dietary habits. The questions were designed to determine the proportion of subjects’ diet that consisted of unprocessed foods (such as fruits, whole grains, and fresh vegetables), and ultra-processed foods. Respondents were then divided into four groups according to their level of intake of processed foods. The demographic group with the highest consumption of ultra-processed foods consisted mainly of younger volunteers, women, and Caucasians. This group tended to have higher education levels and lower rates of smoking and alcohol intake. They engaged in less physical activity and had a lower frequency of comorbidities, but a higher frequency of depressive symptoms.

“In the US, lower-income households typically consume more ultra-processed foods, which are very cheap there. In Brazil, in contrast, the higher people’s income, the higher their intake of ultra-processed foods,” says biologist Natália Gonçalves, the lead author of the study and a researcher in the Department of Pathology at the University of São Paulo (USP) School of Medicine.

Each group’s cognitive performance was tested via cognition assessments. Subjects who derived more than 20% of their daily calories from ultra-processed foods showed a 28% faster overall decline in cognition compared to those who consumed less than 20% of their energy from such foods. Furthermore, the decline in executive function, which is closely linked to a person’s ability to control thoughts and actions, was 25% faster in individuals who consumed a high amount of ultra-processed foods.

According to the researchers, the cognitive loss identified in the study can make tasks such as short-term information storage and retrieval, resuming an activity after a pause, or reading in a noisy environment slightly more challenging. Brain capacity, including executive function, naturally begins to decline, albeit slowly, from around the age of 25 and this decline becomes more pronounced with age. Gonçalves notes that “this is normal. What we are attempting to determine is whether a healthy diet with low intake of ultra-processed foods can prevent these effects from occurring prematurely.”

Studies exploring potential associations between two parameters, such as the consumption of ultra-processed foods and the occurrence of disease or deaths, have limitations. They indicate strong statistical correlations suggesting that changing one variable leads to changes in the other. In the current study, the amount of processed food consumed appears to influence the onset of diseases and the number of premature deaths. However, these studies are unable to demonstrate the underlying mechanism behind this apparent correlation.

Claudia Suemoto, a researcher at the USP School of Medicine, who coordinated the Elsa study on ultra-processed foods and cognitive performance, hopes to address this limitation soon. She plans to conduct brain imaging on volunteers to investigate whether high intake of ultra-processed foods can cause ischemic events or mild strokes that could impair cognitive function over time. “This will enable us to investigate the potential mechanisms behind the association from a structural perspective,” says Suemoto.

The determinants of healthy brain aging in the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil) (nº 20/09468-9); Grant Mechanism Thematic Project; Principal Investigator Alessandra Carvalho Goulart (USP); Investment R$4,202,332.88.

Scientific articles
NILSON, E. A. F. et al. Premature deaths attributable to the consumption of ultra-processed foods in Brazil. American Journal of Preventive Medicine. Vol. 64, no. Jan. 1, 2023.
GONÇALVES, N. G. et al. Consumption of ultra-processed foods and cognitive decline in the Elsa – Brasil study: A prospective study. JAMA Neurology. Dec. 5, 2022.