In a narrow sense, cod liver oil is an oil extracted from the liver of marine fish. Broadly speaking, cod liver oil also includes the liver oil of whales, seals and other marine animals. It is a yellow transparent liquid at room temperature, with a slight fishy smell. It is often used to prevent and treat night blindness, keratomalacia, rickets and osteomalacia, and also has protective effect on epidermal tissues such as upper respiratory mucosa. It is mainly composed of fatty glycerides with high unsaturation, in addition to a small amount of phospholipids and unsaponifiable substances. Cod and turbot are traditional raw materials for producing cod liver oil in the world. China mainly uses sharks, rays, large yellow croaker, mackerel and bamboo pod fish.
The main thing about cod liver oil is that it can't be eaten with seafood. Eating together is very likely to be poisoned.
Taboos for taking cod liver oil: 1) taking too much cod liver oil, 2) taking cod liver oil equals fish oil, and 3) taking cod liver oil pills in large quantities for a long time will inevitably increase the absorption of calcium and phosphorus by the human body. Drink plenty of water at ordinary times, increase urine excretion and prevent calcium precipitation. People with urinary calculi or weak constitution should not take cod liver oil to avoid aggravating the symptoms of calculi or poisoning.