Quality of plant-based diets and healthy aging: A community-based prospective cohort study

Although the global interest in plant-based diets is rising due to their environmental and health benefits, little is known about how plant-based diets and their quality relate to health aging. This study examined the associations of three plant-based diet indices with healthy aging in a community-based cohort of 6817 middle-aged and older adults.

Using data from a validated food frequency questionnaire, three plant-based diet indices were calculated based on quality of plant-based foods [overall plant-based diet index (PDI), healthful plant-based diet index (hPDI), and unhealthful plant-based diet index (uPDI)]. Healthy aging was defined as the absence of major chronic diseases (cardiovascular diseases, type 2 diabetes, cancer, chronic obstructive pulmonary disease, end-stage renal disease), cognitive and physical functional impairments, and mental illness. Risk of unhealthy aging was assessed by multivariable Cox proportional hazards regression including demographics, lifestyle factors, and medical history.

During 16 years of prospective follow-up, 4258 did not achieve healthy aging. After multivariable adjustment, higher scores of uPDI were associated with an increased risk of unhealthy aging, with extreme-quartile hazard ratio (HR) compared with the lowest quartile = 1.12 (95 % CI, 1.02-1.24; P-trend = 0.021). PDI and hPDI scores were not associated with healthy aging. When assessing the associations of uPDI with each domain of healthy aging, uPDI scores were positively associated with chronic diseases [HR (95 % CI): 1.15 (1.01-1.31); P-trend = 0.033)], physical function [HR (95 % CI): 1.13 (1.00-1.27); P-trend = 0.020)], cognitive function domains [HR (95 % CI): 1.46 (1.19-1.79); P-trend = 0.001)], but not with mental health domain [HR (95 % CI): 1.03 (0.89-1.18); P-trend = 0.471].

Higher intake of unhealthy plant foods is associated with an increased risk of not achieving healthy aging. These findings highlight the importance of limiting the excessive consumption of less healthy plant-based foods, such as refined grains and sugary beverages, rather than simply adopting a vegetarian diet, to achieve healthy aging.