Wards off infection Cod liver oil, rich in Vitamins A and D, helps children to resist infection. It also helps the body to make use of calcium, the substance which forms bones and teeth. Orange juice contains the important Vitamin C, essential for all-round health and vitality, for healthy gums and teeth and a clear complexion. Although there are oranges in the shops from time to time, it isn't enough to depend on these. All children should have cod liver Cod liver oil and orange juice are available for all children up to five.