Vitamin C is a water-soluble vitamin. All animals and plants are capable of producing it, except humans.
Vitamin A is a fat-soluble vitamin found in two different forms in nature.
Principal natural sources of Vitamin A
Animal sources: The active form of Vitamin A (also known as retinol) is found in fish oils, liver, egg yolks, butter, whole milk and cheese.
Plant sources: Here it is found as beta-carotene or pro-vitamin A, in certain fruits (including melon, apricot and raspberry), leafy green vegetables (including spinach and broccoli), carrots, pumpkins or squashes, cabbage, potatoes and palm oil.
It must be remembered that beta-carotene content is proportional to intensity of colour: therefore, more carotene is found in orange or yellow fruits and vegetables and in dark green leaves, where it is masked by chlorophyll.
Properties of Vitamin A
Vitamin A is an antioxidant that plays a part in the normal function of the immune system and can defend the body against hostile outside influences.
It also contributes to normal metabolism of iron and helps maintain good vision and healthy and normal skin.
Recommended Daily Intake
The recommended intake varies between 300 mcg daily for babies to 1.4 mg daily for populations with increased needs, such as nursing women, sporting persons or smokers. The average recommended daily intake has been set at 800 mcg daily in the form of retinol, equivalent to 2.4 mg of beta-carotene. This is the amount provided by 100 g of fish or 400 g of carrots.
For whom ?
Vitamin A deficiency can be caused by insufficient dietary intake and also by disruption to digestive processes.