fat-soluble vitamins
4 interactions related to fat-soluble vitamins
omega-3 + vitamin d
Fat from omega-3 supports absorption of the fat-soluble vitamin D
vitamin d + vitamin k2
Vitamin D and vitamin K2 act synergistically on calcium metabolism: vitamin D increases calcium absorption while vitamin K2 activates osteocalcin and matrix Gla protein to direct calcium into bone and away from soft tissue. The main caution is for people taking warfarin.
vitamin d3 + vitamin a
Vitamin D and vitamin A act through partnered nuclear receptors. Vitamin D's active form binds the vitamin D receptor (VDR), which pairs with the retinoid X receptor (RXR) — whose ligand comes from vitamin A — to switch on genes for immunity, epithelial health, and bone. Adequate levels of both support this signaling, but at extreme doses they can work against each other for calcium and bone endpoints, where a controlled human study showed high preformed vitamin A blunting vitamin D's calcium response.
fat-soluble vitamins + dietary fat
Vitamins A, D, E, and K depend on bile-driven micelle formation in the small intestine to be absorbed, and that process is triggered by dietary fat. Taking these vitamins with a fat-free meal or on an empty stomach reduces how much you absorb, while taking them with a meal that contains some fat improves absorption. Controlled studies in vitamin D show meaningfully greater absorption when the supplement is taken with fat.