Researchers looked at data from participants with cardiometabolic conditions across three major observational studies:

• 55,000 adults from the U.K. Biobank (2006–2022)
• 18,000 adults from the U.S. National Health and Nutrition Examination Study (NHANES) (1999–2018)
• nearly 4,500 adults from the Chinese Longitudinal Healthy Longevity Study (CLHLS) (2006–2018)

They evaluated participants’ diets at a single time point based on 24-hour dietary recall interviews or diet questionnaires that were conducted at the start of each study. While widely used, this method depends on the accuracy of self-reported data and does not account for potential changes in eating habits over time.

The researchers then assigned each participant a score on two plant-based diet indexes: healthful and unhealthful.

The healthful plant-based diet index scored higher for those who reported consuming more healthy plant-based foods, such as vegetables, fruits, whole grains, legumes, tea, and coffee.

In contrast, participants who reported eating more refined grains, potatoes, sugar-sweetened drinks, and animal-based foods scored higher on the unhealthful plant-based diet index.

In their analysis, researchers utilized statistical methods to estimate the risk of death over time. They considered factors that could influence the outcomes, including demographics like age and sex, as well as other dietary and lifestyle factors.

The study results indicate that individuals with cardiometabolic conditions could potentially extend their life span by embracing a healthy, plant-based diet.

Specifically, closely following a healthy plant-based diet was associated with a 17% to 24% lower risk of death from any cause, cardiovascular disease, or cancer.

Meanwhile, adhering more closely to an unhealthy plant-based diet was linked to increases in the risk of death from these causes by 28% to 36%.

These results were consistent across subgroup analyses by age, race, sex, body mass index, smoking, alcohol intake, physical activity levels, and different cardiometabolic conditions.

Additionally, while the U.K. and U.S. participants were much younger (averaging 57 and 59 years old) than the Chinese participants (averaging 84 years old), the results remained consistent across different countries.

These findings are observational and don’t prove cause and effect. However, they highlight the potential of healthy plant-based diets to improve health outcomes, especially for those with cardiometabolic conditions.

“We plan to further investigate the associations of plant-based diets with mortality and life expectancy among these patients with different races, nationalities, and socioeconomic status (e.g., Latin American populations),” Zhangling Chen, MD, PhD, of the Department of Cardiovascular Medicine at the Second Xiangya Hospital of Central South University in Changsha, China, and the study’s lead author, told Medical News Today.

“These future investigations can refine our understanding of plant-based diets in relation to cardiometabolic health, tailoring interventions to diverse populations and cultural contexts to improve cardiometabolic health,” Chen said.

Cardiometabolic conditions are influenced by genetic, environmental, and lifestyle factors, with diet acting as a crucial determinant.

This study emphasizes the importance of overall dietary patterns, particularly the varying effects of healthy versus unhealthy plant-based diets, in managing these conditions and reducing the risk of premature death.

Thomas M. Holland, MD, MS, a physician-scientist and assistant professor at the RUSH Institute for Healthy Aging, RUSH University, College of Health Sciences, who was not involved in the study, explained how these diets influence cardiometabolic health.

“The differences in mortality risk between a healthy plant-based diet and an unhealthy plant-based diet are in large part driven by their effects on lipid metabolism (cholesterol), blood sugar control, inflammation, and vascular health,” he stated.

He further explained that a healthy plant-based diet—rich in vegetables, fruits, whole grains, legumes, nuts, and healthy beverages—can support cardiometabolic health by:

• lowering LDL cholesterol and triglycerides while improving HDL cholesterol, reducing heart attack and stroke risk
• enhancing insulin sensitivity and glucose metabolism, aiding diabetes management, and reducing complications
• reducing oxidative stress and chronic inflammation, key drivers of cardiovascular disease
• improving endothelial function and vascular flexibility for better heart health

“[A]n unhealthy plant-based diet, high in refined sugars and grains, sugar-sweetened beverages, and processed plant-based foods, can worsen cardiometabolic outcomes by increasing blood sugar spikes, promoting inflammation and oxidative stress, and impairing lipid metabolism, ultimately leading to a higher risk of heart disease and potentially early mortality.”
— Thomas M. Holland, MD, MS

Additionally, Holland noted that while diet is a significant factor in cardiometabolic health, factors like stress, sleep, and social determinants can also influence cardiometabolic outcomes.

While it’s clear that a healthy plant-based diet may enhance cardiometabolic health and reduce mortality risk, how exactly might it accomplish this? Chen primarily attributes this to the diet’s nutrient composition.

“A healthful plant-based diet may reduce mortality in individuals with cardiometabolic disorders mainly through the potential beneficial effects of nutrients in healthy plant-based foods,” Chen stated.

According to Chen, these nutrients include:

• dietary fiber
• plant fat (like monounsaturated fat and polyunsaturated fat)
• plant protein
• antioxidants (like chlorogenic acids and melanoidins)
• phytoestrogens (like lignans)
• vitamins (like vitamin E and folate)
• minerals (like calcium, potassium, and magnesium)

“Growing evidence has indicated that these nutrients are significantly associated with lower risk of cardiometabolic diseases, thereby reducing risk of premature deaths,” Chen said.

Holland agreed, offering concrete examples of how nutrients in healthy plant-based diets can enhance cardiometabolic health.

For instance, he said that “consuming fiber-rich whole grains and legumes helps regulate blood sugar, while healthy fats from nuts, extra virgin olive oil, and avocado oil support heart health by lowering LDL and raising HDL cholesterol.”