The study builds upon prior research that identified foods that are a win-win for both health and the environment — such as whole grains, fruit, non-starchy vegetables, nuts, and unsaturated oils — as well as foods that could be harmful to the environment and human health, like eggs and red and processed meats.
The new findings suggest eating more planet-friendly foods can help reduce a person’s risk of death from causes such as cancer, heart disease, respiratory diseases, and neurodegenerative diseases and also reduce impacts to the environment in terms of factors like water use, land use, nutrient pollution, and greenhouse gas emissions.
“We proposed a new diet score that incorporates the best current scientific evidence of food effects on both health and the environment,” said Linh Bui, doctoral candidate in the Department of Nutrition at Harvard TH Chan School of Public Health.
“The results confirmed our hypothesis that a higher Planetary Health Diet score was associated with a lower risk of mortality,” Bui added.
With the new study, the researchers aimed to create a simple tool that policymakers and public health practitioners could use to develop strategies to improve public health and address the climate crisis.
“As a millennial, I have always been concerned about mitigating human impacts on the environment,” said Bui. “A sustainable dietary pattern should not only be healthy but also consistent within planetary boundaries for greenhouse gas emissions and other environmental parameters.”
To create their Planetary Health Diet Index (PHDI), researchers reviewed existing research on the relationships between various food groups and health outcomes of over 100,000 participants in two large studies.
The data set included over 47,000 deaths during a follow-up period spanning over three decades from 1986-2018.
Overall, they found that people in the highest quintile (the top one-fifth of participants) for PHDI had a 25 per cent lower risk of death from any cause compared to those in the lowest quintile.
Higher PHDI scores were associated with a 15 per cent lower risk of death from cancer or cardiovascular diseases, a 20 per cent lower risk of death from neurodegenerative disease, and a 50 per cent lower risk of death from respiratory diseases.
However, Bui cautioned that the PHDI does not necessarily reflect all food items and their relationships with all major diseases in all countries, as it may vary with specific health conditions, religious restrictions, or food accessibility.
The findings were presented at the ongoing NUTRITION 2023, the flagship annual meeting of the American Society for Nutrition held from July 22-25 in Boston, US.
–IANS
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