Quick guide to Carotenes
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Description
Carotenes are substances found in food which can be converted to vitamin A as the body requires. Beta carotene is the best known of the carotenes as it is readily converted to vitamin A and is abundant in many foods. Other carotenes include lycopene, alpha carotene, lutein and zeaxanthin.
Carotenes are also beneficial because they act as antioxidants and help to protect the body against heart disease, cancer, eye damage and other disorders.
Absorption and metabolism
Carotenes require fat and bile acids for absorption.
Deficiency
Diets low in carotenes may lead to increased risk of cancer and heart disease.
Sources
Good sources include yellow, orange and dark green fruits and vegetables such as sweet potatoes, carrots, broccoli, spinach and apricots. Some carotenes are used by the food industry as yellow food colouring.
Daily recommended dietary intakes
There is no RDA for beta carotene. Some experts recommend a daily intake of 10 to 30 mg.
Toxic effects of excess intake
Beta carotene is safe even at high doses. Some areas of skin may become orange/yellow in colour if high doses are taken for long periods. This clears when intake is reduced. There is the possibility of menstrual abnormalities with long-term excessive intake.
Therapeutic uses of supplements
Beta carotene supplements have been used to prevent cancer, heart disease, autoimmune diseases and eye damage; and to boost immune function. Lycopene may help to prevent prostate cancer and lutein may help to prevent macular degeneration.
Cautions
Recent research suggests that large doses of beta carotene may actually increase the risk of cancer in those who drink alcohol and smoke heavily.