People who eat environmentally friendly foods have 25% lower mortality risk

Key takeaways:

• A new diet score incorporates evidence on the impact that certain foods have on health and the environment.
• Foods that are good for the planet were linked to lower mortality risks for CVD, cancer and more.

BOSTON — People who consumed more environmentally friendly foods were less likely to die over a 30-year follow-up period than those who did not, according to research presented at NUTRITION.

The EAT-Lancet Commission proposed a healthy dietary pattern in 2019 that could sustainably feed the increasing global population, as well as reduce food waste and improve agricultural practices, Linh P. Bui, MPH, a PhD candidate in the department of nutrition at Harvard T.H. Chan School of Public Health, and colleagues reported.

“As a millennial, I have always been concerned about mitigating human impacts on the environment,” Bui said in a press release. “A sustainable dietary pattern should not only be healthy but also consistent within planetary boundaries for greenhouse gas emissions and other environmental parameters.”

To quantify adherence to the diet, the researchers developed the Planetary Health Diet Index (PHDI) by evaluating existing research on the associations between food groups and health outcomes based on the EAT-Lancet reference diet. According to the press release, Bui and colleagues sought to develop a simple tool that public health practitioners and policymakers could use to create strategies that address the climate crisis and public health.

“We proposed a new diet score that incorporates the best current scientific evidence of food effects on both health and the environment,” Bui said in the release.

They then studied the connections between PHDI and mortality of more than 100,000 people in two prospective cohorts of men and women in the United States who were followed from 1986 to 2018. During this time, the researchers observed more than 47,000 deaths.

The participants in the highest quintile for PHDI had a 25% lower risk for death from any cause compared with those in the lowest quintile, according to the researchers.

Specifically, Bui and colleagues found that PHDI was strongly linked to a lower risk for death from:

• cancer (HR = 0.85; 95% CI, 0.8-0.91);
• CVD (HR = 0.86; 95% CI, 0.81-0.92);
• neurodegenerative diseases (HR = 0.79; 95% CI, 0.73-0.86); and
• respiratory diseases (HR = 0.5; 95% CI, 0.45-0.56).

This translates to a 15% lower mortality risk from cancer or CVD, a 20% lower risk from neurodegenerative disease and a 50% lower risk from respiratory diseases, according to the release.

Women in the highest PHDI quintiles had an added benefit of a lower risk for death from infectious diseases (HR = 0.51; 95% CI, 0.38-0.7).

“The results confirmed our hypothesis that a higher Planetary Health Diet score was associated with a lower risk of mortality,” Bui said. “We hope that researchers can adapt this index to specific food cultures and validate how it is associated with chronic diseases and environmental impacts such as carbon footprint, water footprint, and land use in other populations.”

Reference:

• Bui L, et al. Planetary Health Diet Index and risk of total and cause specific mortality in two prospective cohort studies. Presented at: NUTRITION; July 22-25, 2023; Boston.