Large-scale study presents findings on implications of plant vs animal ultra-processed foods on cardiovascular disease risk

By Pooja Toshniwal PahariaReviewed by Danielle Ellis, B.Sc.Jun 13 2024

In a recent study published in The Lancet Regional Health-Europe, researchers explored the role of ultra-processed foods (UPF) in the association between plant-based food intake and its effect on cardiovascular disease (CVD) outcomes.

Background

CVD is the primary cause of early death globally, posing a considerable financial burden. Promoting good food habits is a cost-effective way to avoid CVD. Plant-based diets, which omit dairy products, eggs, meat, and fish, have been linked to a lower incidence of chronic diseases. However, these diets may contain UPF, which is associated with an increased risk of cardiometabolic illnesses, mental health issues, and death.

The precise methods by which the foods affect health are unknown, although their uneven nutritional content, unique physical forms, and chemical compositions might be possible mechanisms.

About the study

In the present study, researchers investigated cardiovascular disease risk among British individuals based on their dietary intake of food groups of plant or animal origin and food processing categories.

The researchers specifically investigated the effects of ingesting plant-origin non-UPF and plant-based UPF on CVD risk and CVD-related death. They also considered the dietary contribution of non-red meat, excluding only red meat from this group. They also distinguished these non-red meat foods depending on the amount of UPF.

The team analyzed data provided by United Kingdom Biobank participants (40 to 69 years) who completed two or more 24-hour diet recalls between 2009 and 2012 (n=126,842; median follow-up: nine years), with data linked to hospitalization and mortality records. Food groups included plant-sourced or animal-sourced foods, divided into UPF and non-UPF groups, expressed as a proportion of the total calorie intake.

The researchers assessed dietary intakes using validated, online, self-administered questionnaires. They used the NOVA system to classify foods as unprocessed or minimally processed, processed culinary ingredients, processed foods, and ultra-processed foods. Plant-sourced foods included foods exclusively or primarily of plant origin (e.g., vegetables, fruits, breads, and grains). Animal-sourced foods included meats (like poultry, fish, and red meat), eggs, and dairy products.

The team ascertained new-onset cardiovascular disease as the initial hospitalization or death from cardiovascular diseases using the International Classification of Diseases, tenth revision (ICD-10) codes. Cox proportional hazards regression modeling yielded hazard ratios (HR) for analysis. Study variables included age, biological sex, ethnicity, the Index of Multiple Deprivation (IMD), region, physical activity, body mass index (BMI), family history, and smoking status.

The researchers also performed sensitivity analyses, adjusting for animal-origin UPF, red meat, alcohol intake, free sugars, saturated fat, sodium density, fiber density, diabetes mellitus type 2, and hypertension. Additional analyses considered dietary groups as fractions of regular gram intake and adjusted for total regular calorie intake, excluding individuals followed for less than two years.

Results

The study involved 118,397 individuals (mean age, 56 years), with 57% being female. The upper quartile of plant-origin non-UPF participants were older, non-white, more physically active, female previous smokers with a lower BMI, and living in less deprived areas. Conversely, the profiles of individuals stratified by plant-origin UPF contributions showed opposite characteristics.

Plant-origin foods contributed 70% to the diet, with 39% UPF and 31% non-UPF. Concerning the remaining diet, 21% was obtained from animal-origin non-UPFs and 9.0% from animal-origin UPFs. In total, 7.806 incident CVD events and 529 deaths occurred over 1,076,104 individual years, including 6,006 coronary heart disease and 2,112 cerebrovascular events.

A 10% elevation in plant-origin non-UPF intake was related to a 7% lower cardiovascular disease risk (HR, 0.9) and a 13% lower cardiovascular disease-related mortality risk (HR, 0.9). Conversely, plant-origin UPF intake increased the risk of cardiovascular disease by 5.0% and related mortality by 12% (HR, 1.1 for each 10% rise in contributions). UPF contributed to higher cardiovascular disease risk and mortality (HR, 1.1 for contribution increased by 10%) without associations between the contribution of plant-origin foods and cardiovascular disease incidence and related deaths.

Sensitivity analyses yielded similar results. Substituting 10% of plant-origin UPFs, animal-origin non-UPFs, or animal-origin UPFs with an equivalent quantity of calories from plant-based non-UPFs lowered cardiovascular disease and coronary artery disease risks. The substitutions showed similar findings concerning CVD-related mortality, except for replacing energy from animal-based UPFs with plant-based non-UPFs, which showed some protection, although not statistically significant.

Conclusion

The study findings showed that plant-based non-UPF reduces CVD risk, whereas plant-based UPF has a favorable correlation. Replacing plant-based UPF with non-UPF decreased CVD incidence and death by 7.0% and 15%, respectively.

The study advises a move toward plant-based diet choices while considering food processing for better cardiovascular disease outcomes. Future studies should emphasize lowering meat, red meat, and animal-derived meals while avoiding all UPF.