Does Zetia Block Omega Fatty Acids?
No, Zetia (ezetimibe) does not block omega fatty acids—it selectively inhibits only cholesterol absorption without affecting the absorption of triglycerides, fat-soluble vitamins, or other fatty acids.
Mechanism of Selective Cholesterol Inhibition
Ezetimibe works through a highly specific molecular mechanism that distinguishes it from other lipid-lowering agents:
- Ezetimibe targets the Niemann-Pick C1-Like 1 (NPC1L1) protein at the brush border of the small intestine, which specifically blocks cholesterol uptake into enterocytes 1
- This selective mechanism prevents both dietary and biliary cholesterol from entering the bloodstream while leaving other nutrients unaffected 2
- The drug localizes at the intestinal wall and binds to NPC1L1, keeping cholesterol in the intestinal lumen for excretion 3
What Ezetimibe Does NOT Block
The evidence is clear and consistent across multiple sources regarding ezetimibe's selectivity:
- Ezetimibe does not affect the absorption of fat-soluble vitamins, triglycerides, or bile acids 3, 4
- Unlike bile acid sequestrants (which can interfere with absorption of fat-soluble vitamins and other medications), ezetimibe's selective mechanism makes it unique among intestinally-acting lipid-lowering agents 1
- The drug inhibits cholesterol absorption by approximately 54-58% while having no effect on other sterols or lipid-soluble nutrients 3, 5
Clinical Implications
This selectivity is a key advantage of ezetimibe in clinical practice:
- Omega-3 fatty acids and other essential fatty acids are absorbed normally when taking ezetimibe 6
- Patients can continue omega fatty acid supplementation without concern for reduced absorption
- The drug's mechanism is complementary to statins, with ezetimibe blocking intestinal cholesterol absorption while statins inhibit hepatic cholesterol synthesis 2
Common pitfall to avoid: Do not confuse ezetimibe with bile acid sequestrants (like cholestyramine), which can interfere with absorption of various nutrients and medications—ezetimibe's mechanism is entirely different and highly selective for cholesterol only 1, 6.