VITAMIN A

• The amount of vitamin A you consumer is very important as both deficiency and toxicity of this vitamin can cause severe problems

• There is a very narrow range of optimal intakes between these two states

• Vitamin A is found in foods in a variety of forms

• Retinoid or preformed vitamin A, are only found in foods of animal origin, such as fish and organ meats

• Plants contain pigments called carotenoids, which can be turned into vitamin A in the body as needed

• They can be termed provitamin A

• Beta-carotene, the orange-yellow pigment in carrots, if the most potent form of provitamin A

FUNCTIONS OF VITAMIN A AND CAROTENOIDS

Vision:

• Vitamin A performs important functions in light-dark vision, and to a lesser extent, color vision

Cardiovascular Disease Prevention

• Carotenoids may play a role in preventing cardiovascular disease in persons at high risk, possibly linked to carotenoids’ antioxidant capability

Caner prevention

• Coupled with its ability to aid immune system activity, vitamin A may be a valuable tool in the fight against cancer

• Carotenoids by themselves also may help prevent cancer, acting again as antioxidants

• Cancer of the prostate gland is one of the most common cancers among North American men

• Dietary carotenoid lycopene- red pigment found in tomatoes, watermelon, and other fruits

• The proposed biological role of lycopene again may be that of an antioxidant

VITAMIN A SOURCES AND NEEDS

• Vitamin A is found in liver, fish , fish oils, fortified milk and yogurt and eggs

• Provitamin A carotenoids mentioned before are mainly found in dark green and yellow-orange vegetables and some fruits

• Carrots, spinach, and other greens, winter squash, sweet potatoes, broccoli, mangoes, cantaloupe, peaches and apricots are examples of such sources

Category: Biochemistry Notes