Plant-Based Planetary Health Diet Cuts Cardiovascular Risk 28% in Postmenopausal Women, New Study Finds

Postmenopausal women who closely followed a plant-forward eating pattern known as the Planetary Health Diet had roughly a 28% lower risk of developing cardiovascular disease over a 20-year period, according to new research presented this week at a major nutrition science conference.

A large, long-running study

The findings come from an analysis of 66,892 participants in the Women's Health Initiative, a long-term national health study funded by the National Heart, Lung and Blood Institute at the National Institutes of Health. All participants were free of cardiovascular disease at the start of the study, which began enrolling women between 1994 and 1998, and all had complete dietary and lifestyle information available for analysis. The women were around 63 years old at the study's outset and were followed for approximately 20 years to track whether and when they developed cardiovascular disease.

Researchers assessed participants' diets using a food frequency questionnaire administered at the beginning of the study, then calculated a Planetary Health Diet Index score for each woman based on her reported eating habits. Higher scores reflected closer alignment with the Planetary Health Diet, which emphasizes fruits, vegetables, whole grains, legumes, nuts and unsaturated fats while limiting red and processed meats, added sugars, refined grains and saturated fats. Participants were then divided into five groups based on how closely their diets matched the pattern.

A meaningful reduction in risk

Women in the group whose diets most closely followed the Planetary Health Diet showed the lowest overall risk of cardiovascular disease compared with women in the lowest-adherence group, a reduction of approximately 28%. Importantly, the benefit wasn't limited to women who adhered near-perfectly to the diet. Researchers found that even moderate adherence was linked to a measurable reduction in risk, with each 10-point increase in a participant's Planetary Health Diet Index score associated with further risk reduction.

The study didn't stop at overall cardiovascular disease. Donya Shahamati, a doctoral student in public health at the University of California, Irvine, and the study's presenting researcher, explained why the team examined multiple specific outcomes rather than a single combined measure. "We did not only look at overall cardiovascular disease," Shahamati said. "We also looked separately at coronary heart disease, stroke and heart failure." That breakdown allowed researchers to see whether the protective association held consistently across different types of cardiovascular events, and the results showed the pattern was broadly similar across coronary heart disease, stroke and heart failure individually, not just when combined into an overall cardiovascular disease measure.

A reassuring message about dietary flexibility

One of the study's key takeaways, according to Shahamati, is that women don't need to pursue dietary perfection to see meaningful cardiovascular benefits. "Our results suggest that people may not need to follow a perfect or very restrictive diet to see potential heart-health benefits," Shahamati said, adding that the finding carries particular relevance for postmenopausal women specifically, since cardiovascular risk tends to climb with age and often accelerates further after menopause.

Shahamati also offered practical guidance for women interested in shifting their eating patterns closer to the Planetary Health Diet without overhauling their entire diet at once. "Moving toward a more plant-forward, higher-quality diet can be accomplished through small, realistic changes," she said, suggesting steps such as filling half a plate with vegetables more regularly, substituting avocado or olive oil for butter, choosing oatmeal or whole-grain cereal for breakfast, or incorporating one meatless meal per week.

Adjusting for other factors

To help isolate the specific relationship between diet and cardiovascular outcomes, researchers statistically adjusted their analysis for a range of other factors known to influence heart disease risk, including participants' age, race and ethnicity, education, income, smoking status, alcohol intake, physical activity levels, body mass index and total calorie intake. Even after accounting for those variables, the association between higher Planetary Health Diet adherence and lower cardiovascular risk persisted.

Important caveats about the research

As with any observational study, the researchers were careful to note that their findings cannot prove that following the Planetary Health Diet directly caused the reduced cardiovascular risk observed among participants. Diet was assessed only once, at the beginning of the two-decade study period, meaning the analysis does not capture how participants' eating habits may have changed over time. The findings were also presented as a poster session at the conference, meaning they have been reviewed by an expert committee for presentation but have not yet undergone the standard peer-review process required for publication in a scientific journal, a step that typically follows conference presentations of this kind before findings are considered fully validated by the broader scientific community.

A conference bringing together nutrition researchers

Shahamati presented the findings at NUTRITION 2026, the flagship annual meeting of the American Society for Nutrition, held July 25 through 28 in National Harbor, Maryland, just outside Washington, D.C. The conference draws nutrition researchers from around the country to share emerging findings across a broad range of dietary and public health topics, with the Planetary Health Diet study representing one of several presentations this year examining how specific eating patterns relate to long-term chronic disease risk.

Shahamati and her research team said they plan to continue examining diet and health patterns in older adult populations, including how diet quality changes over time within this same group of women, research that could eventually help inform strategies to support healthy aging and reduce the risk of chronic disease later in life. In the meantime, the current findings add to a growing body of research suggesting that plant-forward eating patterns, even when followed imperfectly, may offer meaningful cardiovascular benefits for older women navigating the years following menopause, when heart disease risk tends to rise most sharply.