We examined the association between high-density lipoprotein cholesterol (HDL-C), and exercise and vegetarian diets, in Taiwanese adults, based on the Methylenetetrahydrofolate reductase (MTHFR) rs1801133 polymorphism. Using regression models, we analyzed historical data collected from 9255 Taiwan Biobank (TWB) participants from 2008 through 2015. Exposure to exercise was associated with higher HDL-C (β = 1.0508 and 1.4011 for GG and GA + AA individuals, respectively), whereas a vegetarian diet was associated with lower HDL-C (β = -6.2793 and -4.6359 for those with GG and GA + AA genotype, respectively). We found an interaction between exercise and diet among GG individuals (p = 0.0101). Compared with no exercise/no vegetarian diet, vegetarian diet/no exercise was associated with a 5.1514 mg/dl reduction in HDL-C among those with GG genotype (β = -5.1514, p < 0.0001) and a 4.8426 mg/dl reduction (β = -4.8426, p < 0.0001) among those with GA + AA genotype. Vegetarian diets in combination with exercise predicted a 6.5552 mg/dl reduction in HDL-C among GG individuals (β = -6.5552) and a 2.8668 mg/dl reduction among GA + AA individuals (p < 0.05). These findings demonstrated that vegetarian diet alone was associated with lower HDL-C, no matter the rs1801133 genotype. However, the inclusion of regular exercise predicted much lower levels among GG individuals, whereas levels among GA + AA individuals were relatively higher.
Keywords: biobank; diet; exercise; lipids; polymorphism.