Administration of large oral doses of
retinyl palmitate has become the most widely practised
vitamin A deficiency prevention strategy in developing countries. We conducted a follow-up study among 220 Senegalese children aged 2-7 years suffering from moderate
undernutrition to determine the efficacy of
vitamin A treatment on their
vitamin A status assessed by biochemical and cytological (impression cytology with transfer) methods. The first examination (T = 0 m[onth]) was carried out during April 1989, before the mango (Mangifera indica L,) harvest. The second examination (T = 2 m) was carried out 2 months after
vitamin A treatment during June 1989 when ripe mangoes become widely available. Conjunctival cells of the eyes of the children with or without ocular
inflammation were responsive to
vitamin A administration (P < 0.01). There was a significant increase (P < 0.001) in mean serum
retinol and
beta-carotene levels between T = 0 m and T = 2 m. Mean serum
retinol-binding protein (RBP) and
transthyretin (TTR) levels did not differ significantly (P > 0.05) at T = 0 m and T = 2 m. Despite the intake of
vitamin A, 54% of the children who had abnormal cytology at T = 0 m remained abnormal at T = 2 m. This was due to inadequate levels of TTR and RBP, presumably due to the cereal diet eaten by the Senegalese population. children with abnormal eye cytology had lower serum
retinol levels than those with normal eyes at T = 0 m, and
beta-carotene values did not correlate with eye cytological abnormalities at T = 0 m. Children with normal cytology had higher serum
retinol and also
beta-carotene levels than those with abnormal cytology after massive oral doses of
vitamin A and consumption of mangoes at T = 2 m.
Retinyl palmitate may, therefore, only lead to partial cytological improvement due to a lack of
retinol-
carrier proteins but dietary
beta-carotene may also be involved.