Cross-sectional and longitudinal comparisons of metabolic profiles between vegetarian and non-vegetarian subjects: a matched cohort study

Several previous cross-sectional studies have shown that vegetarians have a better metabolic profile than non-vegetarians, suggesting that a vegetarian dietary pattern may help prevent chronic degenerative diseases. However, longitudinal studies on the impact of vegetarian diets on metabolic traits are scarce. We studied how several sub-types of vegetarian diets affect metabolic traits, including waist circumference, BMI, systolic blood pressure (SBP), diastolic blood pressure, fasting blood glucose, total cholesterol (TC), HDL, LDL, TAG and TC:HDL ratio, through both cross-sectional and longitudinal study designs. The study used the MJ Health Screening database, with data collected from 1994 to 2008 in Taiwan, which included 4415 lacto-ovo-vegetarians, 1855 lacto-vegetarians and 1913 vegans; each vegetarian was matched with five non-vegetarians based on age, sex and study site. In the longitudinal follow-up, each additional year of vegan diet lowered the risk of obesity by 7 % (95 % CI 0·88, 0·99), whereas each additional year of lacto-vegetarian diet lowered the risk of elevated SBP by 8 % (95 % CI 0·85, 0·99) and elevated glucose by 7 % (95 % CI 0·87, 0·99), and each additional year of ovo-lacto-vegetarian diet increased abnormal HDL by 7 % (95 % CI 1·03, 1·12), compared with non-vegetarians. In the cross-sectional comparisons, all sub-types of vegetarians had lower likelihoods of abnormalities compared with non-vegetarians on all metabolic traits (P