Toxic Damage to the Respiratory Epithelium Induces Acute Phase Changes in Vitamin A Metabolism without Depleting Retinol Stores of South African Children , ,

Abstract

Whereas there is much information concerning the effects of vitamin A status on response to infectious challenge, the effects of infection or trauma on vitamin A metabolism and status are less well documented. These relationships need to be understood to optimize clinical and public health programs to improve vitamin A status and health of children in less-developed countries. We measured acute changes in retinol and retinol-binding protein in 57 young South African children hospitalized following respiratory epithelial damage resulting from accidental ingestion of kerosene. In addition, vitamin A status, as measured by the modified relative dose response test, of these children 3 mo later was compared with that of neighborhood control children to determine whether their illness had depleted retinol stores. Plasma retinol was already significantly below control levels when children were admitted [geometric mean (95% CI): 0.57 micromol/L (0.48-0.67) compared with 1.15 micromol/L (1.02-1.30) for controls] and decreased further the following morning [0.38 micromol/L (0.31-0.46)]. Significant differences in retinol-binding protein were not detected until the next morning [5.99 mg/L (4.70-7.63) compared with 14.0 mg/L (11.8-16.6) for controls] and were not as large as the relative differences in retinol. This dissociation between changes in retinol and its binding protein suggests that there may be increased retinol uptake by certain tissues during the acute phase response. The proportion of case children (37/46, 80%) with inadequate liver retinol stores 3 mo after the illness was slightly, but not significantly (chi2 = 2.16, P = 0.14), greater than the proportion of control children (28/42, 67%). Acute respiratory illness therefore did not further deplete retinol stores in this population in which stores were already frequently inadequate.

Undernutrition, the Acute Phase Response to Infection, and Its Effects on Micronutrient Status Indicators

“…However, in children, serum retinol concentrations are suppressed by~25% during common infections (23,124,148) and up to 69% in children with Shigellosis (127). This decrease in serum retinol concentration is independent of vitamin A liver reserves (173). Therefore, individuals who are experiencing infection but have an adequate vitamin A status may be misclassified as deficient, leading to overestimation of deficiency prevalence in a population.…”

Age and Gender as Factors in the Distribution of Global Micronutrient Deficiencies

“…18 While boys in school in South Africa were found to have a serum retinol level below the recommended level, 19 a sample taken from South-African hospitals found no significant difference by gender. 20 Consequently, the a priori assumption that boys are always more at risk than girls requires revisiting. Of the 35 studies in which boys do not have more deficiencies than girls, 25 (71%) found no significant differences.…”

Vitamin A and causes of maternal mortality: association and biological plausibility

“…In acute phase reaction, there is a transient decrease in the production of small molecular weight proteins, including RBP, and an increase in the permeability of renal epithelial cells. Decreased vitamin A might also be due to increased uptake of retinol by certain tissues 25 . PRI could be reduced through three main pathways: promotion of wound healing; increased resistance to infection; and immune enhancement if infection occurs.…”