How does the quality of a plant-based diet affect mortality risk? Original paper

In this prospective cohort study, high adherence to an unhealthful plant-based diet was associated with an increased risk of all-cause mortality and cardiovascular disease mortality.

Whether adherence to a provegetarian diet (PVG) is associated with the risk of all-cause mortality, cardiovascular disease (CVD) mortality, or cancer mortality.

597 older adults (aged 65 and older; 54% women, 46% men) who lived in the province of Alicante, Spain.

A prospective cohort study with a follow-up duration of 12 years was performed. Dietary intake over the past year was assessed at baseline using a food frequency questionnaire, and this data was used to determine adherence to a PVG, a healthful PVG (hPVG), and an unhealthful PVG (uPVG). The participants were divided into groups based on whether they had low, moderate, or high adherence.

For the PVG, higher intakes of any plant-based food contributed positively to the score. For the hPVG, only the intake of vegetables, fruits, legumes, boiled potatoes, nuts, olive oil, and tea and coffee contributed positively to the score, whereas the intake of refined grains, fries and chips, fruit juices and sugar-sweetened beverages, and sweets and desserts contributed negatively to the score. The uPVG was the inverse of the hPVG (e.g., the foods that contributed negatively to the hPVG score contributed positively to the uPVG score). Animal-based products contributed negatively to all scores.

The analyses were adjusted for various confounders, including age, sex, education, waist circumference, sleep duration, smoking, alcohol consumption, disease status, and the number of hours spent watching television per day.

Compared to low hPVG adherence, moderate adherence was associated with a 41% lower risk and a 53% lower risk of all-cause mortality and CVD mortality, respectively. There were no associations for high hPVG adherence.

Compared to low uPVG adherence, high adherence was associated with a 53% higher risk and a 110% higher risk of all-cause mortality and CVD mortality, respectively.