Brun, Pierre-Jacques Department of Medicine, Columbia University, New York, New York.
Blaner, William S. Department of Medicine, Columbia University, Presbyterian Hospital, New York, New York.
- Dietary sources and requirements
- Deficiency and toxicity
- Additional Readings
All-trans-retinol, an essential micronutrient that must be obtained from the diet in order to maintain good health. Vitamin A is required for maintaining vision, a healthy immune response, normal male and female reproduction, normal embryonic development, and healthy skin and barrier functions. At the cellular level, vitamin A acts essentially in vision and in regulating normal cell growth and differentiation. In vision, vitamin A serves as the visual pigment that responds directly to light. The role of vitamin A in regulating normal cell growth and differentiation involves its actions in regulating gene transcription. Both insufficient dietary vitamin A intake and excessive dietary vitamin A intake result in adverse consequences for the health of an individual. See also: Food; Malnutrition; Nutrition; Vitamin
The content above is only an excerpt.
for your institution. Subscribe
To learn more about subscribing to AccessScience, or to request a no-risk trial of this award-winning scientific reference for your institution, fill in your information and a member of our Sales Team will contact you as soon as possible.
to your librarian. Recommend
Let your librarian know about the award-winning gateway to the most trustworthy and accurate scientific information.
AccessScience provides the most accurate and trustworthy scientific information available.
Recognized as an award-winning gateway to scientific knowledge, AccessScience is an amazing online resource that contains high-quality reference material written specifically for students. Contributors include more than 9000 highly qualified scientists and 43 Nobel Prize winners.
MORE THAN 8500 articles and Research Reviews covering all major scientific disciplines and encompassing the McGraw-Hill Encyclopedia of Science & Technology and McGraw-Hill Yearbook of Science & Technology
115,000-PLUS definitions from the McGraw-Hill Dictionary of Scientific and Technical Terms
3000 biographies of notable scientific figures
MORE THAN 19,000 downloadable images and animations illustrating key topics
ENGAGING VIDEOS highlighting the life and work of award-winning scientists
SUGGESTIONS FOR FURTHER STUDY and additional readings to guide students to deeper understanding and research
LINKS TO CITABLE LITERATURE help students expand their knowledge using primary sources of information