Plant-Based Diet Quality Is Associated with Cardiometabolic Health in Adults: A Cross-Sectional Analysis of the Australian Health Survey

Background/Objectives: Evidence suggests that plant-based dietary patterns are beneficial for cardiometabolic health. However, it is unclear whether the quality of plant-based dietary patterns is differentially associated with cardiometabolic health. This study aimed to examine the association between three plant-based diet quality indices and cardiometabolic health among Australian adults. 

Methods: Data on 4877 adults (mean 45.1 years) from the cross-sectional Australian Health Survey 2011–2013 were used. Three plant-based diet quality indices (overall, healthful, and unhealthful) were derived from two 24 h dietary recalls. Anthropometric measures and blood pressure were assessed by trained interviewers. High-risk waist circumference was classified as ≥80 cm in females and ≥80 cm in males. Hypertension was defined as >140/90 mmHg. Fasting blood samples were used to estimate lipid profiles and diabetes status (based on plasma glucose or HbA1c). Multivariate logistic regression analyses were used to investigate the association between plant-based diet indices and cardiometabolic markers. 

Results: The healthy plant-based diet index was associated with lower odds of a high-risk waist circumference (OR 0.98; 95%CI 0.96–0.99), and the unhealthy plant-based diet index was associated with increased odds of having hypertension (OR 1.02; 95%CI 1.00–1.04). No other significant associations were identified between the plant-based diet quality indices and cardiometabolic outcomes. 

Conclusions: There was some evidence that the quality of plant-based dietary patterns was differentially associated with cardiometabolic health, with healthier plant-based dietary patterns associated with lower odds of a high-risk waist circumference, and less healthy plant-based dietary patterns associated with increased odds of hypertension. These findings support the consideration of the quality of plant foods consumed, and the need for targeted advice for optimising cardiometabolic health among adults.