Dietary Reference Intakes The Essential Guide to Nutrient Requirements (2006) / Chapter Skim
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From page 170... ...
TABLE 1 Dietary Reference Intakes for Vitamin A by Life Stage Group DRI values (mg RAEa/day) EARb RDAc AId ULe,f males females males females Life stage group 0 through 6 mo 400 600 7 through 12 mo 500 600 1 through 3 y 210 210 300 300 600 4 through 8 y 275 275 400 400 900 9 through 13 y 445 420 600 600 1,700 14 through 18 y 630 485 900 700 2,800 19 through 30 y 625 500 900 700 3,000 31 through 50 y 625 500 900 700 3,000 51 through 70 y 625 500 900 700 3,000 > 70 y 625 500 900 700 3,000 Pregnancy £ 18 y 530 750 2,800 19 through 50 y 550 770 3,000 Lactation £ 18 y 885 1,200 2,800 19 through 50 y 900 1,300 3,000 a RAE = Retinol activity equivalent.
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From page 171... ...
PART III: VITAMIN A 171 VITAMIN A V itamin A is a fat-soluble nutrient that is important for vision, gene ex pression, reproduction, embryonic development, growth, and immune function. Forms of vitamin A include retinol (preformed vitamin A)
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From page 172... ...
DRIs: THE ESSENTIAL GUIDE TO NUTRIENT REQUIREMENTS 172 VITAMIN A AND THE BODY Function Vitamin A is a fat-soluble vitamin that is important for normal vision, gene expression, reproduction, embryonic development, growth, and immune func tion. Forms of vitamin A include retinol (preformed vitamin A)
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From page 173... ...
PART III: VITAMIN A 173 in a process that depends on the availability of retinol binding protein (RBP)
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From page 174... ...
DRIs: THE ESSENTIAL GUIDE TO NUTRIENT REQUIREMENTS 174 Retinol Activity Equivalents (RAEs) Based on data demonstrating that the efficiency of absorption of b-carotene is less than what has been traditionally thought, retinol activity equivalents (RAEs)
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From page 175... ...
PART III: VITAMIN A 175 contain only vitamin A activity from preformed vitamin A (retinol) , no adjustment is necessary.
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From page 176... ...
DRIs: THE ESSENTIAL GUIDE TO NUTRIENT REQUIREMENTS 176 Pregnancy £18 y Age-specific requirement + estimated daily accumulation by fetus 19 through 50 y Age-specific requirement + estimated daily accumulation by fetus Lactation £18 y Age-specific requirement + average amount of vitamin A secreted in human milk 19 through 50 y Age-specific requirement + average amount of vitamin A secreted in human milk The UL The Tolerable Upper Intake Level (UL) is the highest level of daily nutrient intake that is likely to pose no risk of adverse effects for almost all people.
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From page 177... ...
PART III: VITAMIN A 177 DIETARY SOURCES Foods Preformed vitamin A (retinol) is found naturally in animal-based foods, whereas dietary carotenoids, which are converted to vitamin A in the body, are present in oils, fruits, and vegetables.
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From page 178... ...
DRIs: THE ESSENTIAL GUIDE TO NUTRIENT REQUIREMENTS 178 TABLE 2 Potential Interactions with Other Dietary Substances Substance Potential Interaction Notes SUBSTANCES THAT AFFECT VITAMIN A Dietary fat Dietary fat may enhance the Research results in this area are mixed. absorption of vitamin A and provitamin A carotenoids.
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From page 179... ...
PART III: VITAMIN A 179 INADEQUATE INTAKE AND DEFICIENCY The most specific clinical effect of inadequate vitamin A intake is xerophthalmia, which is estimated to affect 3 million to 10 million children (mostly in developing countries) annually.
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From page 180... ...
DRIs: THE ESSENTIAL GUIDE TO NUTRIENT REQUIREMENTS 180 normalities, reduced bone mineral density, and disorders of the central nervous system. More research is needed to clarify whether chronic vitamin A intake may lead to loss in bone mineral density and a consequent increased risk of hip fracture in certain population groups, particularly among premenopausal and postmenopausal women.
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From page 181... ...
PART III: VITAMIN A 181 KEY POINTS FOR VITAMIN A Vitamin A is a fat-soluble vitamin that is important for normal 3 vision, gene expression, reproduction, embryonic development, growth, and immune function. The requirements for vitamin A are now denoted in retinol 3 activity equivalents (RAEs)
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