New study reveals that the type of ultra-processed food you eat could make all the difference in your heart health, some may be worse than others, while a few might surprise you.
Study: Ultra-processed foods and cardiovascular disease: analysis of three large US prospective cohorts and a systematic review and meta-analysis of prospective cohort studies. Image Credit: Rimma Bondarenko / Shutterstock
In a recent study published in the journal The Lancet Regional Health – Americas, a group of researchers conducted a comprehensive evaluation of the link between ultra-processed food (UPF) intake and coronary heart disease (CHD), cardiovascular disease (CVD), and stroke in the United States (U.S.) cohorts, supported by a systematic review and meta-analysis.
Background
UPF are products with ingredients that enhance profitability, taste, and shelf-life, often including additives like stabilizers, sweeteners, and emulsifiers. In the U.S., UPF accounts for 57% of adults' energy intake and is linked to CVD their high content of excess calories, unhealthy fats, added sugars, and sodium. UPF also contains harmful compounds produced from processing and packaging, contributing to inflammation, diabetes, and atherosclerosis (hardening and narrowing of arteries due to plaque buildup). Despite evidence linking UPF to CVD, gaps remain, especially regarding the impact of different types of UPF on cardiovascular health. Further research is needed to clarify the differential effects of various types of UPF on cardiovascular health and to address gaps in diverse population studies.
About the study
The present study involved three prospective cohorts: the Nurses' Health Study (NHS), which began in 1976 with 121,701 female nurses aged 30-55 years; the Nurses' Health Study II (NHSII), initiated in 1989 with 116,340 women aged 25-42 years; and the Health Professionals Follow-Up Study (HPFS), which started in 1986 with 51,529 men aged 40-75 years. Participants were excluded if they only completed the baseline questionnaire, had a history of CVD or cancer at baseline, or had a body mass index (BMI) outside the 15-50 kg/m² range. After exclusions, the analyses included 75,735 participants from NHS, 90,813 from NHSII, and 40,409 from HPFS.
Dietary intake was assessed every 2-4 years using validated food frequency questionnaires linked to the Harvard nutrient content database. Foods were categorized into four groups using the Non-communicable diseases, Overweight, and Vulnerability to food insecurity Analysis (NOVA) classification. UPF were further divided into ten groups based on nutritional composition. Daily energy and UPF intake were calculated, with the latter expressed as a percentage of total energy intake and divided into quintiles. The study also used the Alternative Healthy Eating Index (AHEI) and a modified version to assess diet quality.
The primary outcomes included incident CHD, stroke, and a composite CVD outcome. Non-fatal cases were identified through self-reports on biennial questionnaires, with physicians confirming cases by reviewing medical records. Statistical analyses were conducted using SAS and Stata, with cohort-specific associations estimated using age- and period-stratified Cox proportional hazards models. To ensure robustness, sensitivity analyses and systematic reviews with meta-analyses were also performed to update evidence on the associations between UPF intake and CVD outcomes.
Study results
In the study, the baseline mean age of participants was 50.8 years for the NHS, 36.7 years for the NHSII, and 53.4 years for the HPFS. Most participants were White, with proportions of 96.4% in NHSII, 97.7% in NHS, and 94.9% in HPFS. The mean contribution of UPF to total caloric intake varied across cohorts, ranging from 15.3-20.8% in the lowest quintile to 42.8-49.6% in the highest quintile, with NHSII participants having the highest UPF intake at 34.4% of total energy intake. The three UPF groups contributing the most to energy intake were bread and cereals, sweet snacks and desserts, and ready-to-eat/heat mixed dishes.. Participants with the highest UPF intake tended to have higher energy intake, lower scores on the AHEI, and higher prevalence of smoking and obesity.
The median follow-up periods were 26.0 years for NHSII, 31.9 years for NHS, and 29.7 years for HPFS. During these periods, the proportion of non-cardiovascular deaths was 20.3% for NHS, 2.7% for NHSII, and 24.3% for HPFS. The study observed a 10.4% loss to follow-up in NHS, 1.5% in NHSII, and 9.8% in HPFS. Pooled hazard ratios (H.R.s) for incident cardiovascular outcomes showed that higher UPF intake was associated with increased risks of CVD and CHD but not stroke. NHSII participants had the highest H.R.s for CVD and CHD compared to NHS and HPFS. Sensitivity analyses confirmed that these associations remained consistent across different models, including those with covariate-specific non-proportional hazards and random-effects models.
Further analyses demonstrated that excluding certain UPF categories, such as hard liquors and yogurt, did not significantly alter the associations for CVD and CHD. However, removing sugar-sweetened beverages and processed meats markedly attenuated the risk estimates for CVD and CHD and reversed the direction of stroke estimates. Adjusting for modified AHEI scores also reduced the H.R.s for CVD and CHD. The associations between UPF intake and CVD outcomes persisted in models stratified by AHEI scores and BMI strata, as well as in four-year lagged analyses. Among UPF groups, processed meats and sugar-sweetened beverages consistently were associated with higher risks of CVD, CHD, and stroke. In contrast, savory snacks and yogurt/dairy-based desserts were inversely associated with CVD and CHD risks.
In the systematic review and meta-analysis, after screening 2,540 publications and 19 cohort studies, with a combined sample of 1,261,040 adults and 63,666 CVD cases, meta-analyses revealed that higher UPF intake was associated with increased risks of CHD, CVD, and stroke, with the strongest evidence for CHD. Sensitivity analyses showed that the findings were robust, and the overall quality of the meta-evidence varied from high for CHD to low for stroke.
Conclusions
To summarize, higher total UPF intake was linked to increased risks of CVD and CHD across multiple cohorts, with robust evidence from 19 studies confirming these associations. Specific UPF categories, like sugar-sweetened and artificially-sweetened beverages and processed meats, were particularly harmful, while some, like cold cereals, savory snacks, and yogurt/dairy-based desserts, were associated with lower risks. These findings emphasize the importance of considering both processing and nutritional quality in dietary advice. Further research in racially and ethnically diverse populations is needed to validate these findings and explore differential UPF impacts across various groups.