Age-related macular degeneration. People who eat a lot of fish and take cod liver oil don’t have a lower risk of developing this condition compared to people who just eat a lot of fish. Irregular heartbeat. Taking cod liver oil by mouth might reduce a specific type of irregular heartbeat in some people. But it’s not known if this reduces the risk of heart-related death. Taking cod liver oil by mouth does not seem to reduce irregular heartbeat in men with irregular heartbeat after a heart attack.
Depression. Taking cod liver oil has been linked with a 29% lower chance of older adults having depression symptoms.
High cholesterol levels in the blood. Taking cod liver oil by mouth doesn’t lower cholesterol levels in people with high cholesterol. But it might increase “good” high-density lipoprotein cholesterol levels in people with type 1 diabetes and high cholesterol. Also, it might lower blood fats called “triglycerides” in men who have had a heart attack. But cod liver oil doesn’t improve these outcomes in people with an inherited form of high cholesterol.
High blood pressure. Taking cod liver oil by mouth seems to slightly lower blood pressure in healthy people and those with slightly high blood pressure. But it’s not clear if this reduction is clinically meaningful for people with very high cholesterol.
Inflammatory bowel disease. Some people with inflammatory bowel disease have joint pain. Taking cod liver oil might reduce joint pain in some people with this condition. Osteoarthritis. Taking cod liver oil along with an NSAID doesn’t reduce swelling in people with osteoarthritis better than taking an NSAID alone. Ear infections in young children. Taking cod liver oil and a multivitamin might reduce the need to use medicine to treat ear infections in young children by about 12%. Airway infections. Giving young children cod liver oil and a multivitamin seems to reduce the number of doctor’s office visits for airway infections.
Rheumatoid arthritis. Taking cod liver oil might decrease pain, morning stiffness, and swelling in some patients with rheumatoid arthritis. Also, taking cod liver oil and fish oil seems to reduce the need to use medicine to treat joint swelling in people with this condition.
Vitamin D deficiency. Taking cod liver oil seems to increase blood levels of vitamin D in some people. But it’s not clear if cod liver oil increases vitamin D to normal levels in people with low levels of vitamin D. Wound healing.