A substance that is converted into a vitamin within an organism.
- ‘It is a fat-soluble substance that is divided into retinol and provitamin A. Retinol is the active form of vitamin A usually found in animal products, while provitamin A is found in fruits and vegetables.’
- ‘The study supports the recommendation of a safe limit to the amount of vitamin A intake for women and confirms that toxicity is not a concern with provitamins such as beta-carotene.’
- ‘However, the Inuit population infrequently consumes vegetables in general, including certain yellow and green ones that contain provitamin A carotene.’
- ‘Beta carotene, a provitamin found in plants and their pigments, is a benign source of vitamin A and is an antioxidant with possible anticarcinogenic properties.’
- ‘Sweet potatoes are also an excellent source of provitamin A, which the body converts into vitamin A.’
We take a look at several popular, though confusing, punctuation marks.