Just a few plant-based swaps a week could make a difference to your heart

Just a little less meat, a little more veg: Researchers show that even small weekly swaps from red or processed meat to plant-based foods can lower your risk of heart disease.

​​​​​​​Study: Partial substitution of red or processed meat with plant-based foods and the risk of cardiovascular disease. ​​​​​​​Image Credit: Chalee2500 / Shutterstock

A modelled study conducted by an international team of researchers found that partially replacing red or processed meat with plant-based foods may reduce the risk of cardiovascular disease. The findings are published in the European Journal of Epidemiology.

Background

Cardiovascular disease is a leading cause of mortality worldwide. Unhealthy dietary habits, such as excessive consumption of red or processed meat, are one of the major risk factors of cardiovascular disease. Given health adversities as well as ethical concerns associated with animal-based foods, a global shift towards plant-based foods has been observed in recent years.

In Finland, an increased consumption of vegetables, fruits, berries, legumes, nuts, and seeds is noticed among men and women between 1997 and 2017. However, red or processed meat consumption remains higher than the current Finnish and Nordic nutrition recommendation of 350 grams per week for 93% of men and 60% of women. In contrast, only 14% of men and 22% of women meet the recommended daily intake of vegetables, fruits, and berries (500 grams per day).

Given the negative impact of red and processed meat on cardiovascular health, the current study was designed to assess cardiovascular health outcomes associated with partial substitution of red or processed meat with plant-based foods among Finnish adults.

Study design

The study analyzed pooled data from five Finnish cohorts involving 42,868 participants aged over 25. Participants' diets were assessed at baseline using a validated food frequency questionnaire, and cardiovascular disease cases developed during the study's median follow-up period of 12.7 years were obtained from national health registers.

The study model included weekly substitutions of 100 grams of red meat or 50 grams of processed meat with similar amounts of legumes, vegetables, fruits, whole grain cereals, or a combination of these.

The main aim was to assess the impact of these substitutions on the risk of cardiovascular disease. A total of 11,031 incident cardiovascular disease cases were identified during the study period.

Study findings

When pooled data was analyzed, the study could not find any association between red and processed meat consumption and cardiovascular disease risk. However, a 15% reduced risk of cardiovascular disease was observed among participants who consumed the highest amount of vegetables. No risk reduction was observed among participants consuming legumes, fruits, and whole-grain cereals.

The study found a small but statistically significant reduction in cardiovascular disease risk among men when processed meat was substituted with vegetables or the combination of plant-based foods (hazard ratio (HR) 0.99, 95% confidence interval (CI) 0.99–1.00, P < 0.05). In contrast, an increased cardiovascular disease risk was observed among women when red meat was substituted with legumes (HR 1.10, 95% CI 1.01–1.20, P < 0.05). However, the effect sizes were modest, with HRs close to 1.00, indicating a minor absolute risk reduction at the individual level.

Considering a shortened follow-up time of 7.9 years, the study found that several plant-based foods reduce cardiovascular disease risk, and none of them increase the risk when partially replacing red or processed meat in men and women. For example, substituting processed meat with legumes or vegetables in men, and substituting red meat with fruits or the combination of plant-based foods in women, were all associated with reduced cardiovascular disease risk.

Study significance

The study finds a beneficial impact of replacing red and processed meat with plant-based foods on cardiovascular disease risk reduction. As specifically observed in the study, replacing processed meat with vegetables or the combination of plant-based foods leads to risk reduction in men over a follow-up period of a median of 12.7 years. However, in women, replacing red meat with legumes leads to an increased risk.

Considering the follow-up period (7.9 years) in the most recent cohort, the study finds that several plant-based foods reduce the risk of cardiovascular disease in both men and women when replacing red or processed meat.

The differences in results between the two follow-up durations may be explained by changes in diet over time in Finland. With a shortened follow-up time, the diet probably included more red and processed meat and fewer plant-based foods compared to the maximum follow-up time, leading to stronger associations in modelled substitutions.

The legume-related increased risk observed among women should be interpreted with caution, as mentioned by researchers. Given the general concept that foods included in substitution analysis should be commonly consumed in the study population, researchers stated that the result is likely related to the low consumption of legumes in the pooled cohorts. Additionally, the confidence intervals for this finding were wide, indicating statistical uncertainty.

Similarly, they could not find additional benefits in risk reduction after replacing red or processed meat with whole grain cereals, because cereal consumption is already high in the pooled cohorts.

It should also be noted that the findings are based on Finnish cohorts, where baseline dietary patterns, such as high whole grain consumption, may differ from those in other countries, potentially limiting the generalizability of the results to other populations.

A moderate-level dietary changes were considered in substitution analyses. With these small, easily implemented substitutions, the study finds improvements in cardiovascular health at the population level. These findings provide an encouraging public health message, demonstrating that even a slight change towards more plant-based diets can reduce the risk of cardiovascular disease, as well as other chronic diseases, such as type 2 diabetes and cancer.

The self-reported dietary assessment methods used in the study may be associated with underreporting, overreporting, and misclassification, which may influence the observed associations.

Furthermore, the study analyzed only baseline dietary data and did not consider potential changes in diet over time. The substitution analyses were based on a gram-for-gram approach, and the study did not use isocaloric substitution; however, the authors note that the modest amounts substituted likely minimize the impact of this limitation. Future studies should consider these factors for more conclusive interpretations.

Overall, while the observed risk reductions are modest at the individual level, the authors emphasize that even small changes in dietary habits can have a meaningful impact on public health, given the high prevalence of cardiovascular disease.