What is vitamin A?
Vitamin A in foods includes members of two chemical families, the retinoids such as retinol, retinal, and retinoic acid, and the carotenoids such as alpha-carotene, beta-carotene, and other carotenes. However, in order for a carotenoid to have vitamin A activity it must first be converted to a retinoid in the body. Therefore, carotenoids are often referred to as provitamin A. Although there are hundreds of carotenoids found in nature, only about 50 may be converted to vitamin A. Furthermore, only about a half dozen of those carotenoids are found in the human diet in appreciable amounts. Because of its availability in the diet and relatively efficient conversion to a vitamin A, beta-carotene may be the most significant carotenoid with regard to conversion to vitamin A.
What foods provide vitamin A?
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Vitamin A in the retinoid form is found in animal products with better sources being liver, fish oils, eggs, and vitamin A-fortified milk and milk products (see Vitamin A in Foods Table). Meanwhile, carotenoids are found in plant sources—mainly in orange and dark green vegetables and some fruits (squash, carrots, spinach, broccoli, papaya, sweet potatoes, pumpkin, cantaloupe, and apricots). In fact, the term carotenoid is derived from the species name for carrots. Nutrition supplements tend to provide vitamin A in the form of retinyl acetate or retinyl palmitate or as beta-carotene. |
FOOD |
Vitamin A
|
FOOD |
Vitamin A
|
|---|---|---|---|
Vegetables |
|
Meats |
|
|
Pumpkin, canned (½ c) |
2712 |
liver (3 oz) |
9124 |
|
sweet potato, canned (½ c) |
1935 |
salmon (3 oz) |
53 |
|
carrots, raw (½ c) |
1913 |
tuna (3 oz) |
14 |
|
spinach, cooked (½ c) |
739 |
Eggs |
|
|
Broccoli, cooked (½ c) |
109 |
Egg (1) |
84 |
|
winter squash (½ c) |
53 |
Milk and milk products* |
|
|
green peppers (½ c) |
40 |
milk, skim (1 c) |
149 |
|
Fruits |
|
milk, 2% (1 c) |
139 |
|
Cantaloupe (¼ whole) |
430 |
cheese, american (1 oz) |
82 |
|
Apricots, canned (½ c) |
210 |
cheese, swiss (1 oz) |
65 |
|
nectarine (1) |
101 |
Fats |
|
|
Watermelon (1 c) |
59 |
Margarine* (1 tsp) |
46 |
|
Peaches, canned (½ c) |
47 |
Butter (1 tsp) |
38 |
|
papaya (½ c) |
20 |
|
|
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