caa a22 4500 388097329 CHVBK 20180307125307.0 cr unu---uuuuu 161130e199905 xx s 000 0 eng 10.1017/S0029665199000403 doi S0029665199000403 pii (NATIONALLICENCE)cambridge-10.1017/S0029665199000403 The effect of vitamin A on epithelial integrity [Elektronische Daten] Vitamin A is the generic term for a variety of fat-soluble substances including retinol, retinyl palmitate and the provitamin A carotenoids such as all-trans-β-carotene. Vitamin A is commonly known as the anti-infective vitamin and has an essential role in vision and cellular differentiation, the latter providing a unique core mechanism helping to explain the influence of vitamin A on epithelial barriers. Alterations in the epithelial lining of vital organs occur early in deficiency, suggesting a potentially important role for the barrier function. Vitamin A deficiency (VAD) is most commonly recognized in the eye. The conjunctival-impression cytology test detects the presence of larger irregular keratinized cells and the absence of mucous-secreting goblet cells, indicative of VAD. The method is simple, quick and sensitive in populations where VAD is present. In the respiratory tract, observational studies all show an association with VAD, although vitamin A supplementation studies appear to have little effect on respiratory disease. Organ-specific targeting may improve success rates. The dual-sugar intestinal-permeability test allows the effect of vitamin A supplementation to be monitored on the gastrointestinal tract. Two vitamin A supplementation studies were carried out recently in Orissa State, India. Healthy infants of weaning age were administered orally eight weekly doses of 5.0 mg retinol equivalents and hospitalized infants received one large oral dose 60 mg retinol equivalents in the form of retinyl palmitate. Improvements in gut integrity and haematological status were observed in both studies. In summary, the response of the eye to vitamin A supplementation is well established; the present review highlights some of the more recent observations examining the effects of vitamin A. Copyright © The Nutrition Society 1999 Vitamin A nationallicence Conjunctival-impression cytology test nationallicence Dual-sugar intestinal-permeability test nationallicence McCullough F. S. W. Northern Ireland Centre for Diet and Health (NICHE), University of Ulster, Coleraine BT52 1SA, UK Northrop-Clewes C. A. Northern Ireland Centre for Diet and Health (NICHE), University of Ulster, Coleraine BT52 1SA, UK Thurnham D. I. Northern Ireland Centre for Diet and Health (NICHE), University of Ulster, Coleraine BT52 1SA, UK Proceedings of the Nutrition Society Cambridge University Press 58/2(1999-05), 289-293 0029-6651 58:2<289 1999 58 PNS https://doi.org/10.1017/S0029665199000403 text/html Onlinezugriff via DOI 1 conference jats NATIONALLICENCE 856 40 https://doi.org/10.1017/S0029665199000403 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- McCullough F. S. W. Northern Ireland Centre for Diet and Health (NICHE), University of Ulster, Coleraine BT52 1SA, UK NATIONALLICENCE 700 1- Northrop-Clewes C. A. Northern Ireland Centre for Diet and Health (NICHE), University of Ulster, Coleraine BT52 1SA, UK NATIONALLICENCE 700 1- Thurnham D. I. Northern Ireland Centre for Diet and Health (NICHE), University of Ulster, Coleraine BT52 1SA, UK NATIONALLICENCE 773 0- Proceedings of the Nutrition Society Cambridge University Press 58/2(1999-05), 289-293 0029-6651 58:2<289 1999 58 PNS CC0 http://creativecommons.org/publicdomain/zero/1.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-cambridge