![[Feedback]](/icons/banner/feedbackACT.gif){kind=icon}
![[For Subscribers]](/icons/banner/subscriberACT.gif){kind=icon}
![[Archive]](/icons/banner/archiveACT.gif){kind=icon}
![[Search]](/icons/banner/searchACT.gif){kind=icon}
![[Contents]](/icons/banner/tocACT.gif){kind=icon}
|
|
|
|
|
||
Department of Nutritional Sciences, UW-Madison, Madison, WI 53706-1571
3To whom correspondence should be addressed. E-mail: sherry{at}nutrisci.wisc.edu.
Xerophthalmia classification was traditionally used to identify populations with vitamin A deficiency. Currently, night blindness and dark adaptometry have been proposed as population assessment methods. While eye signs and function tests are still used in areas where vitamin A deficiency is severe, a subclinical vitamin A deficiency is more prevalent. Serum and breast milk retinol concentrations are used to identify vitamin A deficiency risk. However, in healthy individuals, serum retinol concentrations are homeostatically controlled and do not begin to decline until liver reserves of vitamin A are dangerously low. Moreover, serum retinol and retinol binding protein (RBP) concentrations fall during times of infection. The RBP:transthyretin ratio may help to determine if serum retinol concentrations are depressed by infection. Other methods better reflect liver reserves of vitamin A, the "gold" standard. The relative dose response and modified relative dose response tests involve giving a small dose of retinyl or dehydroretinyl ester, respectively, and determining a response in the serum at about 5 h. A new response test where retinoyl ß-glucuronide is administered and the degree of hydrolysis to retinoic acid is measured has been investigated. Unlike isotope dilution tests, the dose response tests lack utility in defining the total body reserve of vitamin A. The deuterated retinol isotope dilution test has been used in several different groups. Recently, a new isotope assay was developed using 13C-retinyl acetate and gas chromatography-combustion-isotope ratio mass spectrometry for analysis. Thus, having many choices of vitamin A assessment methods, laboratory sophistication and resources available will usually dictate which methods are chosen.
KEY WORDS: • vitamin A • retinol • vitamin A indicators
This article has been cited by other articles:
|
|
 |
|
  A. L. Escaron, M. H. Green, J. A. Howe, and S. A. Tanumihardjo Mathematical Modeling of Serum 13C-Retinol in Captive Rhesus Monkeys Provides New Insights on Hypervitaminosis A J. Nutr., October 1, 2009; 139(10): 2000 - 2006. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. P. Mills, H. C. Furr, and S. A. Tanumihardjo Retinol to Retinol-Binding Protein (RBP) Is Low in Obese Adults due to Elevated apo-RBP Experimental Biology and Medicine, October 1, 2008; 233(10): 1255 - 1261. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. P. Mills, P. W. Simon, and S. A. Tanumihardjo Biofortified Carrot Intake Enhances Liver Antioxidant Capacity and Vitamin A Status in Mongolian Gerbils J. Nutr., September 1, 2008; 138(9): 1692 - 1698. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 R. L Surles, J. P Mills, A. R Valentine, and S. A Tanumihardjo One-time graded doses of vitamin A to weanling piglets enhance hepatic retinol but do not always prevent vitamin A deficiency Am. J. Clinical Nutrition, October 1, 2007; 86(4): 1045 - 1053. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. P. Mills, P. W. Simon, and S. A. Tanumihardjo {beta}-Carotene from Red Carrot Maintains Vitamin A Status, but Lycopene Bioavailability Is Lower Relative to Tomato Paste in Mongolian Gerbils J. Nutr., June 1, 2007; 137(6): 1395 - 1400. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. K Tchum, S. A Tanumihardjo, S. Newton, B. de Benoist, S. Owusu-Agyei, F. K. Arthur, and A. Tetteh Evaluation of vitamin A supplementation regimens in Ghanaian postpartum mothers with the use of the modified-relative-dose-response test Am. J. Clinical Nutrition, December 1, 2006; 84(6): 1344 - 1349. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. M. Baeten, M. H. Wener, D. D. Bankson, L. Lavreys, B. A. Richardson, K. Mandaliya, J. J. Bwayo, and R. S. McClelland HIV-1 Infection Alters the Retinol-Binding Protein:Transthyretin Ratio Even in the Absence of the Acute Phase Response J. Nutr., June 1, 2006; 136(6): 1624 - 1629. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. L. Surles, J. Li, and S. A. Tanumihardjo The Modified-Relative-Dose-Response Values in Serum and Milk Are Positively Correlated over Time in Lactating Sows with Adequate Vitamin A Status J. Nutr., April 1, 2006; 136(4): 939 - 945. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K. L Penniston and S. A Tanumihardjo The acute and chronic toxic effects of vitamin A Am. J. Clinical Nutrition, February 1, 2006; 83(2): 191 - 201. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
F. T Wieringa and M. A Dijkhuizen Validity of the dose-response tests for the determination of vitamin A status Am. J. Clinical Nutrition, November 1, 2005; 82(5): 1138 - 1139. [Full Text] [PDF]
|
|
|
|
|
|
P. J van Jaarsveld, M. Faber, S. A Tanumihardjo, P. Nestel, C. J Lombard, and A. J S. Benade {beta}-Carotene-rich orange-fleshed sweet potato improves the vitamin A status of primary school children assessed with the modified-relative-dose-response test Am. J. Clinical Nutrition, May 1, 2005; 81(5): 1080 - 1087. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. R Valentine and S. A Tanumihardjo One-time vitamin A supplementation of lactating sows enhances hepatic retinol in their offspring independent of dose size Am. J. Clinical Nutrition, February 1, 2005; 81(2): 427 - 433. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. R. Valentine and S. A. Tanumihardjo Adjustments to the Modified Relative Dose Response (MRDR) Test for Assessment of Vitamin A Status Minimize the Blood Volume Used in Piglets J. Nutr., May 1, 2004; 134(5): 1186 - 1192. [Abstract] [Full Text] [PDF]
|
|
