A 20-year study of more than 65,000 postmenopausal women found that higher adherence to the Planetary Health Diet was associated with a lower risk of overall cardiovascular disease, coronary heart disease, stroke and heart failure, according to findings presented on July 25 at NUTRITION 2026, the annual meeting of the American Society for Nutrition.
The study showed that women whose diets most closely followed the Planetary Health Diet had about a 28% lower risk of cardiovascular disease compared with those in the group scoring lowest for adherence. Even moderate adherence to the diet was linked with a lower risk. The Planetary Health Diet emphasizes foods such as fruits, vegetables, whole grains, legumes, nuts and unsaturated fats while limiting red and processed meats, added sugars, refined grains and saturated fats.
Shahamati said, "Moving toward a more plant-forward, higher-quality diet can be accomplished through small, realistic changes. These changes might include filling half the plate with vegetables more often; using avocado or olive oil in place of butter; choosing oatmeal or whole-grain cereal for breakfast; or trying a meatless meal once per week."
The research included 66,892 participants from the Women's Health Initiative (WHI), 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 baseline between 1994-1998 and had complete information on diet and other health factors. Researchers used food frequency questionnaires to calculate each participant's Planetary Health Diet Index score and divided them into five groups based on alignment with this dietary pattern.
Participants were around age 63 at enrollment and followed for approximately two decades to track development of cardiovascular disease. The researchers adjusted their analysis for several factors including age, race/ethnicity, education level, income status, smoking habits, alcohol intake, physical activity levels, body mass index and total calorie intake.
Shahamati said, "We did not only look at overall cardiovascular disease. We also looked separately at coronary heart disease, stroke and heart failure. This helped us see whether the pattern was similar across different types of cardiovascular outcomes." The results indicated that closer alignment with the Planetary Health Diet corresponded to decreased risks across all these conditions compared to those least aligned with it.
Researchers noted that even moderate adherence led to reduced risk; each 10-point increase in diet index score brought further reduction in risk. However, they cautioned that because this is an observational study, it cannot prove causation between diet and reduced cardiovascular events.
The research team is continuing work exploring other aspects of diet quality over time among older adults—information they say could help support healthy aging.
