Gastro-intestinal transit time and serum lipid levels in Black schoolchildren

Gastro-intestinal transit time was measured in 150-200 Black schoolchildren, aged 10-12 years, at each of 3 schools in country areas of South Africa. Pupils were accustomed to a low fat/high crude fibre diet. At each centre, a selection was made of 50 children with fast transit times (9 hours or less), and 50 with relatively slow times (roughly 24 hours or more). Fasting levels of serum cholesterol and triglyceride were determined in these subjects. At two schools there were no significant differences in mean lipid levels between subjects with fast and slow transit: only at the third school were mean lipid levels of pupils slightly, but significantly lower in those with fast transit times. These observations agree with those on White adults, that an increase in intake of fibre-containing foods, and a decrease in transit time, have very little effect on serum lipid levels. The low values in Black children are believed to be due primarily to their low intakes of fat and cholesterol.