Ultra-processed foods linked to CVD death, diabetes, mental disorders

High consumption of ultra-processed foods appears to increase the risk of all-cause mortality, cardiovascular disease (CVD)-related mortality, common mental disorders, overweight and obesity, and type 2 diabetes (T2D), reveals the results of an umbrella review of epidemiological meta-analyses.

“These findings provide a rationale to develop and evaluate the effectiveness of using population-based and public health measures to target and reduce dietary exposure to ultra-processed foods for improved human health,” the researchers said.

This umbrella review obtained data from Medline, PsycINFO, Embase, and the Cochrane Database of Systematic Reviews, as well as reference lists from 2009 to June 2023. The researchers identified eligible systematic reviews and meta-analyses of cohort, case-control, and/or cross-sectional studies. The GRADE* framework was used to assess the quality of evidence.

Forty-five unique analyses, including 13 dose-response associations and 32 nondose-response associations (n=9,888,373), met the eligibility criteria. Overall, exposure to ultra-processed foods directly correlated with 32 (71 percent) health parameters, including mortality, cancer, and mental, respiratory, cardiovascular, gastrointestinal, and metabolic health outcomes. [BMJ 2024;384:e077310]

Based on convincing evidence (class I), higher exposure to ultra-processed foods had direct associations with increased risks of incident CVD-related death (risk ratio [RR], 1.50, 95 percent confidence interval [CI], 1.37‒1.63; GRADE=very low) and T2D (dose-response RR, 1.12, 95 percent CI, 1.11‒1.13; moderate), as well as prevalent anxiety outcomes (odds ratio [OR], 1.48, 95 percent CI, 1.37‒1.59; low) and combined common mental disorder outcomes (OR, 1.53, 95 percent CI, 1.43‒1.63; low).

Highly suggestive (class II) evidence also showed direct associations between higher exposure to ultra-processed foods and greater risks of incident all-cause death (RR, 1.21, 95 percent CI, 1.15‒1.27; low), heart disease-related death (hazard ratio [HR], 1.66, 95 percent CI, 1.51‒1.84k; low), T2D (OR, 1.40, 95 percent CI, 1.23‒1.59; low), and depressive outcomes (HR, 1.22, 95 percent CI, 1.16‒1.28; low), as well as prevalent adverse sleep-related outcomes (OR, 1.41, 95 percent CI, 1.24‒1.61; low), wheezing (RR, 1.40, 95 percent CI, 1.27‒1.55; low), and obesity (OR, 1.55, 95 percent CI, 1.36‒1.77; low).

“Evidence for the associations of ultra-processed food exposure with asthma, gastrointestinal health, some cancers, and intermediate cardiometabolic risk factors remains limited and warrants further investigation,” the researchers said.

Furthermore, 21 of the remaining 34 pooled analysis were graded as suggestive or weak strength (class III‒IV), and 13 were as no evidence (class V). Using the GRADE framework, 22 pooled analyses were found to be low quality, with 19 rated as very low quality and four as moderate quality.

Nutrition

Diets rich in ultra-processed foods have been shown to contain higher levels of added sugars, saturated fat, and sodium; higher energy density; and lower fibre, protein, and micronutrients. [Nutrients 2021;13:3390; Eur J Nutr 2022;61:1801-1812]

Moreover, ultra-processed foods often take the place of more nutritious foods in the table, such as fruits, vegetables and nuts, thus reducing consumption of beneficial bioactive compounds present in these healthful foods, including polyphenols and phytoestrogens. [Int J Food Sci Nutr 2023;74:338-349; Nutrients 2017;9:209]

“Coupled with existing population-based strategies, we recommend urgent mechanistic research and the development and evaluation of comprehensive population-based and public health strategies, including government-led policy frameworks and dietary guidelines, aimed at targeting and reducing dietary exposure to ultra-processed foods for improved human health,” the researchers said.

*Grading of Recommendations, Assessment, Development, and Evaluations