Positive Health Online

Abstract

VIDAILHET and COLLEAGUES,  1. Université de Lorraine, 54000 Nancy, France; 2. Université Montpellier-1, 34000 Montpellier, France; 3. Université de Franche-Comté, 25000 Besançon, France; 4. Service de pédiatrie, université de Lausanne, CHUV, CH-1011 Lausanne, Switzerland; 5. Université Nantes-Atlantique, 44000 Nantes, France; 6. Université Paris Descartes, 75015 Paris, France; 7. Cabinet de pédiatrie, 81000 Albi, France; 8. Université Pierre et Marie Curie-Paris 6, 75006 Paris, France; 9. Université de Tours, Inserm U1069, Tours, France; 10. Université Lille 2, LIRIC-Inserm U995, 59000 Lille, France; 11. Institut de recherche pour le développement, 44, boulevard de Dunkerque, 13572 Marseille, France.  andre.briend@gmail.com updated current knowledge regarding vitamin A deficiency,  one of the main causes of blindness and effects of  periodic supplementation with high doses of vitamin A upon mortality.

Background

Vitamin A (retinol) fulfils multiple functions in vision, cell growth and differentiation, embryogenesis, the maintenance of epithelial barriers and immunity. A large number of enzymes, binding proteins and receptors facilitate its intestinal absorption, hepatic storage, secretion, and distribution to target cells. In addition to the preformed retinol of animal origin, some fruits and vegetables are rich in carotenoids with provitamin A precursors such as β-carotene: 6μg of β-carotene corresponds to 1μg retinol equivalent (RE). Carotenoids never cause hypervitaminosis A.

Methodology

Determination of liver retinol concentration, the most reliable marker of vitamin A status, cannot be used in practice. Despite its lack of sensitivity and specificity, the concentration of retinol in blood is used to assess vitamin A status. A blood vitamin A concentration below 0.70μmol/L (200μg/L) indicates insufficient intake. Levels above 1.05μmol/L (300μg/L) indicate an adequate vitamin A status. The recommended dietary intake increases from 250μg RE/day between 7 and 36 months of age to 750μg RE/day between 15 and 17 years of age, which is usually adequate in industrialized countries.

Results

However, intakes often exceed the recommended intake, or even the upper limit (600μg/day), in some non-breastfed infants. The new European regulation on infant and follow-on formulas (2015) will likely limit this excessive intake. In some developing countries, vitamin A deficiency is one of the main causes of blindness and remains a major public health problem. The impact of vitamin A deficiency on mortality was not confirmed by the most recent studies.

Conclusion

Periodic supplementation with high doses of vitamin A is currently questioned and food diversification, fortification or low-dose regular supplementation seem preferable.

References

Vidailhet M1, Rieu D2, Feillet F1, Bocquet A3, Chouraqui JP4, Darmaun D5, Dupont C6, Frelut ML7, Girardet JP8, Hankard R9, Rozé JC5, Siméoni U4, Turck D10, Briend A11. Vitamin A in pediatrics: An update from the Nutrition Committee of the French Society of Pediatrics. Arch Pediatr. 24(3): 288-297. Mar 2017. doi: 10.1016/j.arcped.2016.11.021. Epub Jan 27 2017.