Cod liver oil is a type of fish oil supplement. Like regular fish oil, it is high in Omega-3 fatty acids, which are linked to many health benefits, including reduced inflammation and lower blood pressure. It also contains vitamins A and D, both of which provide many other health benefits. The omega 3-fatty acids in cod liver oil may reduce chronic inflammation by suppressing the proteins that promote it. Cod liver oil is a great dietary source of vitamin D and may reduce age-related bone loss. That is because it helps your body absorb calcium, which is a necessary mineral for strong bones, from the gut. However, the omega-3 fatty acids and vitamin A in cod liver oil have been shown to protect against eye diseases caused by inflammation.