Planetary Health Diet lowers heart risk in older women, study finds

A 20-year study of 66,892 postmenopausal women linked the Planetary Health Diet to lower cardiovascular disease risk.

Women whose eating habits most closely followed the diet had around a 28 per cent lower risk of cardiovascular disease than those in the lowest-adherence group.

Even moderate adherence to the diet was linked with a lower risk.

Donya Shahamati is a doctoral student in public health at the University of California, Irvine.

The researcher said: “Our results suggest that people may not need to follow a perfect or very restrictive diet to see potential heart-health benefits.

“This is especially important for postmenopausal women, because cardiovascular risk increases with age and tends to rise after menopause.”

The diet emphasises fruit, vegetables, whole grains, legumes, nuts and unsaturated fats, while limiting red and processed meats, added sugars, refined grains and saturated fats.

Postmenopausal women are those who have gone through menopause, when periods stop and hormone levels change.

Cardiovascular risk tends to increase with age and rise after menopause.

“Moving towards a more plant-forward, higher-quality diet can be accomplished through small, realistic changes,” said Shahamati.

“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.”

For the research, investigators followed 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 the women included in the analysis were free from cardiovascular disease at the start of the study, between 1994 and 1998, and had complete information about their diet and other important health and lifestyle factors.

Researchers used information collected through a food frequency questionnaire at the start of the study to calculate a Planetary Health Diet Index score for each participant. Higher scores indicated that a participant’s diet was more closely aligned with the Planetary Health Diet.

They then divided the women into five groups according to how closely their diets followed it.

The women were around 63 years old at the start of the study and were followed for about 20 years to see who developed cardiovascular disease.

When analysing the data, researchers adjusted for factors that could affect cardiovascular risk, including age, race and ethnicity, education, income, smoking, alcohol intake, physical activity, body mass index and total calorie intake.

“We did not only look at overall cardiovascular disease,” said Shahamati.

“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.”

Overall, women whose diets were most closely aligned with the Planetary Health Diet had the lowest risk of cardiovascular disease.

They also had a lower risk of coronary heart disease, heart failure and stroke than women in the lowest-adherence group.

Moderate adherence was also associated with a lower risk, with each 10-point increase in the Planetary Health Diet Index score linked to a further reduction.

The researchers cautioned that, because the study was observational, it could not show that the diet directly caused the lower risk among women.

Observational studies identify links between factors such as diet and disease risk, but cannot prove that one caused the other.

The research team is now exploring other aspects of diet and health among older adults, including how diet quality changes over time.

The researchers said this information could help support healthy ageing and prevent chronic diseases.