Health and environmental impacts of plant-rich dietary patterns: a US prospective cohort study

Aviva A Musicus; Dong D Wang; Marie Janiszewski; Gidon Eshel; Stacy A Blondin; Walter Willett; Meir J Stampfer

doi:10.1016/S2542-5196(22)00243-1

Health and environmental impacts of plant-rich dietary patterns: a US prospective cohort study

Lancet Planet Health. 2022 Nov;6(11):e892-e900. doi: 10.1016/S2542-5196(22)00243-1.

Authors

Aviva A Musicus¹, Dong D Wang², Marie Janiszewski³, Gidon Eshel⁴, Stacy A Blondin⁵, Walter Willett⁶, Meir J Stampfer⁶

Affiliations

¹ Department of Nutrition, Harvard T H Chan School of Public Health, Boston, MA, USA. Electronic address: aam231@mail.harvard.edu.
² Department of Nutrition, Harvard T H Chan School of Public Health, Boston, MA, USA; Channing Division for Network Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA.
³ Channing Division for Network Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA.
⁴ Bard College, Annandale-on-Hudson, NY, USA.
⁵ Department of Nutrition, Harvard T H Chan School of Public Health, Boston, MA, USA.
⁶ Department of Nutrition, Harvard T H Chan School of Public Health, Boston, MA, USA; Department of Epidemiology, Harvard T H Chan School of Public Health, Boston, MA, USA; Channing Division for Network Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA.

Abstract

Background: Diets that are rich in animal-based foods threaten planetary and human health, but plant-rich diets have varied health and environmental effects. We aimed to characterise a healthy dietary index and three plant-based indices by their environmental impacts and associations with risk of cardiovascular disease.

Methods: In this prospective cohort study, we used data from a food-frequency questionnaire in the US-based Nurses' Health Study II. Participants were categorised by quintiles of four dietary indices, including the alternative healthy eating index-2010 (AHEI), plant-based diet index (PDI), unhealthy PDI, and healthy PDI. We calculated environmental impacts (greenhouse gas emissions and irrigation water, nitrogenous fertiliser, and high-quality cropland needs), and relative risks (RRs) of cardiovascular disease from 1991-2017, comparing quintiles.

Findings: We included 90 884 participants in the health-impact analysis and 65 625 participants in the environmental-impact analysis. Comparing the top and bottom quintiles, higher AHEI scores were associated with a decreased cardiovascular disease risk (relative risk 0·77 [95% CI 0·66-0·89]); 30% lower greenhouse gas emissions (Q5 2·6 kg CO₂ equivalent vs Q1 3·7 kg CO₂ equivalent); and lower fertiliser, cropland, and water needs (all p_trends<0·0001). Similarly, the highest healthy PDI and PDI quintiles were associated with a decreased cardiovascular disease risk (healthy PDI 0·71 [0·60-0·83] and PDI 0·74 [0·63-0·85]) and lower environmental impacts (PDI water needs p_trend=0·0014; all other p_trends<0·0001). Conversely, the highest unhealthy PDI quintile had a higher cardiovascular disease risk compared with the lowest unhealthy PDI quintile (1·15 [1·00-1·33]; p_trend=0·023) and required more cropland (p_trend<0·0001) and fertiliser (p_trend=0·0008).

Interpretation: Dietary patterns that are associated with better health had lower greenhouse gas emissions and nitrogenous fertiliser, cropland, and irrigation water needs. Not all plant-based diets conferred the same health and environmental benefits. US dietary guidelines should include nuanced consideration of environmental sustainability.

Funding: US National Institutes of Health.

Publication types

Research Support, N.I.H., Extramural

MeSH terms

Carbon Dioxide
Cardiovascular Diseases* / epidemiology
Cardiovascular Diseases* / etiology
Environment
Fertilizers
Greenhouse Gases* / adverse effects
Humans
Prospective Studies
Water

Substances

Greenhouse Gases
Fertilizers
Carbon Dioxide
Water

Abstract

Publication types

MeSH terms

Substances

Grants and funding