Plant-based meat alternatives show no significant heart health benefits in recent study

By Hugo Francisco de SouzaReviewed by Susha Cheriyedath, M.Sc.Jun 28 2024

In a recent study published in The American Journal of Clinical Nutrition, researchers conducted an eight-week-long randomized controlled trial to evaluate the impacts of consuming a plant-based meat analog (PBMA)  diet (PBMD) versus one composed of an omnivorous animal-based one (ABMD). Using linear mixed-effects models, their study comprising 82 participants revealed that while the dietary exposures did differ in their effects on dietary fiber, potassium, sodium (all presenting increases in the PBMD cohort), and dietary trans-fat (increased in the ABMD cohort), no significant improvements in cardiometabolic health biomarkers (lipid-lipoproteins) could be observed.

Contrary to marketing promises and the authors' a priori hypothesis, these findings highlight that in the Asian cohort under investigation, PBMD does not project any statistically notable cardiovascular health benefits over conventional ABMD. Together, these results call for a focus on nutritional quality when developing future PBMAs.

Study: Plant-Based Meat Analogs and Their Effects on Cardiometabolic Health: An 8-Week Randomized Controlled Trial Comparing Plant-Based Meat Analogs With Their Corresponding Animal-Based Foods. Image Credit: Antonina Vlasova / Shutterstock

Background

Despite being naturally omnivorous, religious and cultural edicts have historically resulted in many geographically diverse human communities primarily consuming plant-based diets (PBDs). This observation is particularly prevalent in Asian and Indian regions, wherein some religious sects require their followers to abstain from meat and meat products. In recent years, a resurgence in global PBD popularity has been witnessed, with environmental, health, and animal welfare concerns primarily driving this observation.

Previous research has established vegetarian and vegan diets as healthier than meat-based diets (MBDs), particularly in cardiometabolic outcomes. Furthermore, large and data-rich controlled trials have suggested that the gradual transition from ABD to PBDs can reduce the risk of chronic, non-transmittable diseases. Combined with the aforementioned global spike in PBD interest, these results spurned the invention and development of plant-based meat analogs (PBMAs). These food products aim to mimic the organoleptic properties of meat-based food products while meeting the ethical and health benefits of vegetarian/vegan ones.

Unfortunately, given that PBMAs are still novel introductions, scientific evidence for their health benefits remains severely limited. While a few studies have suggested weight-loss benefits to PBMA consumption, their cardiometabolic risk outcomes are hitherto confounding. Furthermore, research on the topic is almost exclusively conducted in Euporean and American cohorts, leaving the rest of the world data deficit. Despite their genetic predisposition to metabolic diseases, Asians remain notably excluded from the literature.

About the study

In the present study, researchers hypothesize that substituting ABDs with PBMDs will gradually improve human cardiovascular health, observable through a postulated reduction in negative cardiometabolic risk markers. They tested their hypothesis in a publicly sourced (via physical and electronic adverts) Singaporean cohort conducted at the Clinical Nutrition Research Centre, Singapore. Sample screening comprised participants' completion of questionnaire-based lifestyle, food frequency, and health histories.

Study inclusion criteria restricted participants to adult (>30 to ≤70 y) omnivorous (minimum 20g of meat per day) Chinese males and females with elevated blood glucose levels but no diabetes. Frequent smokers and obese participants (BMI f ≥27.5 kg/m² or waist circumference exceeding 88 cm [female] or 102 cm [male]) were excluded from the analysis.

Selected participants were evaluated using standard anthropometric measurement protocols for height, weight, and waist circumference. Fasting (>10 hours), blood glucose, and glycated hemoglobin were recorded using the capillary finger prick method. After baseline evaluations, participants were randomly assigned to the ABMD or PBMD cohort. The eight-week-long parallel design randomized controlled trial intervention comprised participants' gradual substitution of their regular food patterns to research-supplied animal—or plant-analog-based diets.

"These included a selection of 6 frozen foods that were broadly categorized as follows: 1) beef mince, 2) pork mince, 3) chicken breast, 4) burger patty, 5) sausage, and 6) chicken nuggets provided via scheduled deliveries to each participant's home. Corresponding to this list, the PBMD group was provided with the following foods: 1) Impossible Beef (Impossible Foods), 2) OmniMeat Mince (OmniFoods), 3) Chickened Out Chunks (The Vegetarian Butcher), 4) Beyond Burger (Beyond Meat), 5) Beyond Sausage Original Brat (Beyond Meat), and 6) Little Peckers (The Vegetarian Butcher)."

This study's primary outcome of interest was diet-associated low-density lipoprotein changes, while other known cardiovascular risk factors were secondary. Data collection included participants' completion of three-day food records, collected every two weeks during the study period. This dietary data was processed to establish participant-specific macro- and micro-nutrient profiles and to verify participant intervention compliance. Serologic assays were carried out to determine plasma insulin and fructosamine concentrations. A continuous glucose monitor was used to assess the changes in cardiometabolic risk factors during the dietary substitution.

Study findings

Of the 213 participants screened at baseline, 96 met the study inclusion criteria and were assigned in a 1:1 ratio into either ABMD or PBMD cohorts. Over the subsequent eight weeks, 14 participants dropped out, leaving final analyses with 40 PBMD and 42 ABMD datasets. Participants were predominantly female (61%), with a mean age of 59. Participants were healthier than the general populace, with an estimated mean vascular age of 56. Since BMI differed slightly between groups at baseline (PBMD was ~1.3 kg/m² higher than AMBD), this was corrected during linear mixed models.

Dietary evaluations revealed that proteins and saturated fats both presented time effects, wherein values postintervention were substantially higher than at baseline. In contrast, carbohydrate intake was observed to reduce. Protein increases were most prominent in the AMBD cohort, while the PBMD cohort displayed more significant reductions in cholesterol, sodium, and potassium. Study intervention compliance was observed to be high overall – 87% in PBMD and 95% in ABMD participants.

Surprisingly, no effects on lipid-lipoprotein profiles were revealed (LDL cholesterol, the primary outcome of interest, remained unchanged). Framingham 10-y CVD risk indices could not differentiate between either cohort or within-cohort baseline and final readings, ruling out measurable changes in secondary outcomes of interest. Weight and BMI similarly showed no improvements across the eight-week-long study. However, both cohorts displayed net reductions in waist circumference over the study duration.

Conclusions

In summary, the present study was unable to reveal statistically meaningful cardiometabolic benefits to substituting ABMDs with PBMDs in Asian (specifically Singaporean) individuals. Contradicting manufacturers' marketing promises and the authors' only apriori hypothesis, current-generation PBMDs do not reflect the cardiovascular advantages of their constituent plant foods, possibly due to essential nutrient loss during the latters' processing for the formers manufacture.

"…assumptions of health benefits from consuming a PBMD may not be directly extrapolated to those consuming a PBD. However, this creates an opportunity and stimulus for the food industry to re-evaluate the production of next-generation PBMAs with improved nutritional attributes and bioaccessibility. The inclusion of nutrition in the current focus on organoleptic properties and sustainability will be beneficial to both the manufacturers and the consumers in this Asian population and globally."