Study Links Highly Processed Foods to Premature Death

Study Links Highly Processed Foods to Premature Death
A new study from Brazil found an association between ultra-processed foods and an increased risk of premature death. | Image by Oscar Wong/Getty Images

Highly processed foods, like pizza, sugar-sweetened beverages, and ice cream, contribute to premature death, according to a study published in the American Journal of Preventive Medicine on November 7.

The authors suggested a direct link between ultra-processed foods and the deaths of roughly 57,000 individuals aged 30 through 69 in Brazil in 2019. This means that over 10% of annual premature deaths occurring in that age group nationwide were allegedly tied to their consumption practices.

While other studies have uncovered a correlation between processed foods and conditions like heart disease, cancer, diabetes, and cognitive decline, according to the authors, this is the first-time researchers have attempted to quantify the impact on overall longevity.

According to Katherine D. McManus, a registered dietician and teaching affiliate of Harvard Medical School, foods are considered ultra-processed when they undergo multiple processes, such as extraction and milling. These foods often contain additives like artificial colors and stabilizers. In contrast, unprocessed or minimally processed foods, like fruit and nuts, maintain their original nutritional profile.

“The food is in its natural (or nearly natural) state. These foods may be minimally altered by removal of inedible parts, drying, crushing, roasting, boiling, freezing, or pasteurization, to make them suitable to store and safe to consume,” explained McManus.

The researchers involved in the latest study leveraged previously established calculations from a British Journal of Nutrition paper published last year. This study compared the relative risk of premature death for individuals consuming large quantities of ultra-processed foods versus those who consume a very low amount. The same model was subsequently applied to Brazilian data and adjusted for the country’s consumption levels.

The authors discovered that if highly processed foods comprised less than 23% of Brazilian diets, the country could see premature deaths fall by approximately 20,000 a year. While noting that most Brazilians already eat like this, they pointed out that 25% of the adult population still obtain half their daily calories from ultra-processed foods, like cookies, mass-produced bread, cakes, and margarine.

In the United States, the proportion is even higher. On average, 57% of American calories are ultra-processed. As a result, a nutrition researcher at the University of São Paulo and the study’s lead author, Eduardo Nilson, theorizes that the U.S. could see an even greater reduction in premature deaths if fewer processed foods were eaten.

Nilson suspects “that heart disease is among the main factors” driving these premature deaths, with diabetes, cancer, obesity, and chronic kidney disease also contributing.

While the findings are concerning — and potentially valuable — Maura Walker, an assistant professor of nutrition at Boston University, cautioned that they are also inconclusive. The authors have uncovered a correlation, but they have not verified causation, she suggested.

Walker suspects “ultra-processed foods are just one factor that’s leading to things like hypertension, poor blood lipids, higher waist circumferences, and that’s actually how they’re linked to mortality.”

While further research is required to establish how substantial a role processed foods play in longevity, experts agree that reducing their intake is likely wise.

Dr. Walter Willett, a professor of epidemiology and nutrition at the Harvard T.H. Chan School of Public Health, is convinced diets need to change. “In general, there’s no question that Brazilians and Americans and a lot of other people are eating way too much junk food… Collectively, they add up to a big chunk of preventable mortality,” according to Willett.

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