Is cow's milk suitable for the dietary supplementation of rural Gambian children? 1. Prevalence of lactose maldigestion.

To define the age-related prevalence of lactose maldigestion (LM), 218 children aged 13-72 months from a rural Gambian village were studied using a lactose breath hydrogen test. There was a significant rise in LM from 21% to 76% between the 2nd and 3rd-5th years of life (p < 0.001). Only eight children had diarrhoea within 2 weeks before the test. Diarrhoea and abdominal discomfort followed in only seven children (3%). There was no difference in mean time of introduction of supplementary diet or cessation of breastfeeding between children aged 12-36 months with lactose digestion and LM. There was a greater proportion of children with normal lactose digestion than with LM in those still receiving breast milk (85% vs 15%), and a greater proportion of LM in the fully weaned group (63% vs 37%) (p < 0.001). There was no relation between weight-for-age or weight-for-height and the ability to digest lactose. The ability to digest lactose is lost in the majority of children during the 2nd year, coincident with the cessation of breastfeeding, but is not a major factor associated with growth failure thereafter.