●We first investigated the association of dietary choline and betaine intakes with insulin resistance.
●Dietary choline and betaine intakes were negatively correlated with insulin resistance.
●Associations were more pronounced in females than males.
Dietary betaine supplement could ameliorate insulin resistance (IR) in animals, but no data are available for choline. Reports on humans are rare. We aimed to investigate the association between dietary choline and betaine intakes and IR in humans.