The richest readily available dietary source of vitamin A is fish liver oil, especially cod liver. In particular, all–trans dehydroretinol, previously known as vitamin A2, is a vitamin A-related compound found in freshwater fish flesh and liver and to a lesser extent, on some marine fish. Cod liver and halibut fish oil contain high levels of vitamin A and have been used therapeutically.
Margarine, fluid milk and dry milk are typically fortified with retinyl palmitate in many countries. These products play a dramatic role in preventing vitamin A deficiency in countries where fortification is mandatory.
In the United States, milk is fortified with not less than 2000 IU vitamin A (retinyl palmitate).
The principal source of vitamin in the diet is likely to b from the carotenes which are widespread in those plant foods that have high green or yellow coloring.
There is a direct correlation between the greenness of a leaf and its carotene content. Dark green leaves, such as beet greens, collards, dandelion, greens, kale, mustard greens, spinach, Swiss chard, and turnip greens are rich in carotene.
Dietary sources of vitamin A