Can vitamin A be expected to improve child growth?

Vitamin A (VA) is indispensible for mammalian growth. Yet dependence on VA for child growth has been difficult to show. Relative gains in weight (WT), height (HT) or arm circumference (AC) may occur with VA supplementation but most studies show no effect. In Nepal, children 12-60 mo of age with mild xerophthalmia (night blindness or Bitot's spots) (XERO) and at least mild wasting (AC<13.5 cm) (n=34) who were treated with 400,000 IU VA showed mean, relative 16-mo gains in WT, HT, AC and subscapular skinfolds of ≥ 574 g, 0.8 cm, 0.6 cm, and 1.1 mm respectively, over similarly wasted, non-XERO children (n=1187), adjusted for sex, age and initial measure status (all comparisons, p<0.01). Mean 16-mo linear growth of non-wasted (AC>13.5 cm) cases (n=86) improved by a mean of 0.5 cm or more over non-wasted, non-XERO children (n=2187) (p< 0.01). VA had no effect on WT or HT growth of non-XERO children but increased arm muscle area, on average, by 25 mm² (p<0.01). VA can improve growth when VA deficiency is growth-limiting; but the aspect, tempo and frequency of response may be expected to vary by relative severity of VA deficiency, season, duration of dosing and follow-up, and gender. VA deficiency prevention should be motivated by public health goals other than its potential impact on child growth (ie, blindness and mortality prevention).