vitamin A
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Tweet n. Any of various related fat-soluble compounds, especially vitamin A1 (retinol), obtained principally from milk, eggs, and liver or produced in the body from beta carotene in plant foods, and functioning in cell growth and differentiation, the visual system, and the immune system. Vitamin A deficiency can cause blindness and damage to epithelial tissues. |
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2022 by HarperCollins Publishers. All rights reserved.
vitamin A2
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Tweet n. A fat-soluble vitamin, C20H28O, occurring chiefly in freshwater fish and other freshwater vertebrates, where it is a component (in aldehyde form) of the retinal pigment porphyropsin. |
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2022 by HarperCollins Publishers. All rights reserved.
vitamin A1
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Tweet n. A yellow crystalline compound, C20H30O, that is the principal form of vitamin A found in most vertebrates other than freshwater fish. Also called retinol. |
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2022 by HarperCollins Publishers. All rights reserved.