Limit intake of ultra-processed food to prolong life: study

Individuals who regularly eat ultra-processed foods are at greater risk of death, which is driven by causes other than cancer and cardiovascular diseases (CVD), reports a study.

“The associations varied across subgroups of ultra-processed foods, with meat/poultry/seafood-based ready-to-eat products showing particularly strong associations with mortality,” according to the investigators, led by doctoral student Zhe Fang, Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, US.

Fang and colleagues performed this population-based cohort study involving female registered nurses from 11 US states in the Nurses’ Health Study (1984‒2018) and male health professionals from 50 US states in the Health Professionals Follow-up Study (1986‒2018). A total of 74,563 women and 39,501 men with no history of cancer, CVD, or diabetes at baseline were included in the analysis.

Using multivariable Cox proportional hazard models, the investigators estimated the hazard ratios (HR) and 95 percent confidence intervals (CI) for the association of ultra-processed food intake, measured by semiquantitative food frequency questionnaire every 4 years with all-cause and cause-specific mortality (eg, cancer, CVD, respiratory, and neurodegenerative causes).

Of the participants, 30,188 women and 18,005 men died during a median follow-up of 34 and 31 years, respectively. [BMJ 2024;385:e078476]

Participants with the highest consumption of ultra-processed foods had a 4-percent higher all-cause mortality (HR, 1.04, 95 percent CI, 1.01‒1.07) and 9-percent higher mortality from causes other than cancer or CVD (HR, 1.09, 95 percent CI, 1.05‒1.13) than those with the lowest intake. No associations were observed for mortality due to cancer or CVD.

The all-cause mortality rates in the lowest and highest quarter were 1,472 and 1,536 per 100,000 person-years, respectively.

Consistently, ready-to-eat foods such as processed meat were strongly associated with mortality outcomes (HRs ranging from 1.06‒1.43). Likewise, sugar- and artificially sweetened beverages (HR, 1.09, 95 percent CI, 1.07‒1.12), dairy-based desserts (HR, 1.07, 95 percent CI, 1.04‒1.10), and ultra-processed breakfast food (HR, 1.04, 95 percent CI, 1.021‒1.07) correlated with higher all-cause mortality.

“No consistent associations between ultra-processed foods and mortality were observed within each quarter of dietary quality assessed by the Alternative Healthy Eating Index-2010 score, whereas better dietary quality showed an inverse association with mortality within each quarter of ultra-processed foods,” Fang said.

Previous studies also reported the association of ultra-processed food intake with mortality. In a meta-analysis of prospective cohorts, the highest ultra-processed food consumption correlated with greater all-cause mortality than the lowest consumption (HR, 1.21, 95 percent CI, 1.13‒1.30). [Nutrients 2021;14:174]

In contrast, earlier studies reported the inverse association between CVD and consumption of nuts and dark chocolate. In particular, dark chocolate correlated with lower mortality. [J Am Coll Cardiol 2017;70:2519-2532; Eur J Nutr 2020;59:389-397]

“The findings provide support for limiting consumption of certain types of ultra-processed food for long-term health,” Fang said. “Future studies are warranted to improve the classification of ultra-processed foods and confirm our findings in other populations.”