Requirement and Recommended Dietary Allowance (RDA) for Vitamin A?

Recommendations for adequate vitamin A intake based on the amounts needed to correct night blindness among vitamin A deficient subjects and to raise plasma levels in vitamin A deficient individuals to a normal level. The RDA suggested for vitamin A is given in Table (a). You can observe ii.om the values given in the table that the requirements are highest during lactation. This is due to the fact that human milk, particularly cdlostrum is a rich source of vitamin A. It is also evident that the intake recommended for pre-schoolers aid older children are equal to that recommended for adult than and woman. This high level has been suggested keeping in mind the high prevalence sate of clinical vitamin A deficiency in this segment of the population.

Table (b) provides the estimated mew requirements for vitamin A and the recommended safe intakes, taking into account the age and gender differences in mean body weights, as suggested by FAO/WHO report 2004. They are at the upper limits of the range so as to cover the mean dietary requirements of 97.5% of the population.

The recommendations discussed above, have been based on the fact that what level of vitamin A is required to prevent deficiency and also maintain health. In calculating the safe intake, a normative storage requirement equivalent to 434 mg RE/day was taken into consideration. However, when vitamin A deficiency or toxicity is anticipated, it is necessary to assess the existing vitamin A status. This provides vital information regarding the future course of nutrition and medical action which would be necessary to restore back good health. Therefore, we shall now review the criteria for assessment of vitamin A status.