Vitamin A status in children who are prone to respiratory tract infections

Abstract

The effect of Vitamin A supplementation on susceptibility to acute respiratory infections was investigated in a randomized controlled trial. One hundred and forty-seven preschool-age children with a history of frequent respiratory illness were randomized into Vitamin A supplemented (450 pg/day) and placebo groups. Respiratory symptoms were recorded on a daily basis over a period of 11 months. The children who received the supplement experienced 19% fewer episodes of respiratory symptomatology (Pt0.05) than their placebo counterparts, despite the fact that their plasma retinol levels did not change. Children with a prior history of lower respiratory illness or of allergy benefited most from supplementation. The plausibility of a role for Vitamin A in the aetiology of respiratory proneness is reviewed.

Effects of Vitamin A Supplementation on Immune Responses and Correlation with Clinical Outcomes

“…In fact, some of the hospital-based studies suggest an apparent increase in indicators of severity associated with vitamin A supplementation (41,85,105,146). A number of community-based trials have also found an apparent increase in respiratory symptoms in relation to vitamin A supplementation (34,39,103,104,112,136,144), particularly among children who are not undernourished. It is not clear whether this apparent increase in respiratory symptoms may be due to a proinflammatory immune response associated with the supplements.…”

Undernutrition, infection and immune function

“…A recent study (Sempertegui et al 1999) reported that vitamin A (3 mg retinol equivalents per week for 40 weeks) decreased the incidence of lower respiratory tract infections in underweight children compared with placebo treatment, but increased the incidence in normal-weight children. Supplementation of Australian children with a history of respiratory infections caused a reduction in rate of lower respiratory disease of 25 % (Pinnock et al 1986). Shenai et al (1987) reported reduced incidence of bronchopulmonary dysplasia in vitamin A-de®cient low birth weight infants given vitamin A.…”

Meat and cancer: meat as a component of a healthy diet

“…Vitamin A plays a substantial role, especially in the respiratory epithelium and the lung. During moderate vitamin A deficiency, the incidence of diseases of the respiratory tract is considerably increased and repeated respiratory infections can be influenced therapeutically by a moderate vitamin A supplementation (Pinnock et al, 1986a;Sommer, 1993;West et al, 1991). In addition to the importance of the vitamin for lung function, vitamin A is also responsible for the development of many tissues and cells as well as for the embryonic lung development.…”

“…With reduced retinol plasma levels repeated infections are more often described (Barreto et al, 1994;Filteau et al, 1993;Pinnock et al, 1986b) and they are counted among the main complications of a poor vitamin A supply in developing countries. In addition, the serum vitamin A level during infectious diseases, particularly of the respiratory tract, continues to drop (Neuzil et al, 1994).…”