Consumption of highly processed foods linked to increased risk of death

A new study found that older adults who reported consuming greater amounts of ultra-processed foods (as defined by the NOVA classification system) were about 10% more likely to die than those who consumed less processed foods over an average follow-up of 23 years.

The findings are based on a large study that followed more than half a million adults in the United States for nearly three decades. According to the results, higher consumption of ultra-processed foods was associated with a slight increase in deaths from all causes, and particularly deaths related to heart disease or diabetes. However, no association was found for cancer-related deaths.

“Our study results support a larger body of literature, including observational and experimental studies, that suggests that consuming ultra-processed foods negatively impacts health and life expectancy,” said Erikka Loftfield, Ph.D., Stadtman Investigator at the National Cancer Institute. “However, there is still much we don’t know, including which aspects of ultra-processed foods pose potential health risks.”

Loftfield presented the findings at NUTRITION 2024, the flagship annual meeting of the American Society for Nutrition, held June 29-July 2 in Chicago.

The study used data from more than 540,000 people who provided information about their eating habits and health in the mid-1990s, when they were between 50 and 71 years old.

More than half of the participants have since died. The researchers analyzed the overall death rate among those who were in the 90th percentile for consumption of ultra-processed foods at baseline compared to those in the 10th percentile and also examined associations with specific foods and specific diseases.

“We found that ultra-processed meat and soft drinks are among the subgroups of ultra-processed foods most strongly associated with the risk of death. Diets low in these foods are already recommended for disease prevention and health promotion,” Loftfield said. The Dietary Guidelines for Americans recommend limiting sugar-sweetened beverages and processed meats such as hot dogs, sausages and deli meats.

For this study, researchers used several strategies to classify the level of processing of different foods. These included breaking down food frequency questionnaire data by specific food and ingredient types and incorporating expert consensus to categorize food components using a rubric known as the NOVA classification system.

The researchers also took into account other factors that can increase a person’s risk of death, such as smoking and obesity. They found that people who consumed more ultra-processed foods also had a higher body mass index and a lower Healthy Eating Index (a measure of diet quality based on how well a person’s diet meets the Dietary Guidelines for Americans).

However, the analysis showed that the associations between consumption of ultra-processed foods and increased mortality could not be explained by these variables, as the associations between higher intake of ultra-processed foods and risk of death persisted both in people with better and worse diet quality and in people with normal weight and obesity.

One caveat is that the study design did not allow researchers to establish causality. In addition, Loftfield noted that American food supply and dietary habits have changed significantly since the study’s baseline data were collected in the mid-1990s, underscoring the importance of further research to further elucidate the links between food processing and human health.

Please note that abstracts presented at NUTRITION 2024 have been evaluated and selected by a panel of experts, but have generally not undergone the same peer review process required for publication in a scientific journal. Therefore, the results presented should be considered preliminary until a peer-reviewed publication is available.