Vitamin A is a fat-soluble vitamin essential to the maintenance of health. It plays many roles in the body, but it is especially important for the health of epithelial cells. These cells cover the surface of the body (skin and eyes) and body cavities (such as lungs, intestines, mouth, and stomach), serving as barriers to infection. Many of these cells secret mucus, a thick fluid that acts as a protective lubricant, and vitamin A is fundamental to this process. Vitamin A also participates in other processes such as growth, body development and reproduction. Vitamin A deficiency, rare in the US, can lead to blindness, and may impair immune function, increasing the risk for infections.
2010 Dietary Guidelines for Americans
The Dietary Guidelines for Americans is a set of nutritional recommendations for the general public living in the United States that focuses on health promotion and disease prevention. It is a joint effort of the U.S. Department of Health and Human Services (HHS) and the U.S. Department of Agriculture (USDA). The Guidelines are revised and updated every five years; the last one was published in 2010. Policymakers, healthcare providers and nutritionists use these recommendations to design educational materials and nutrition-related programs.