4.3. The Bacon Chow Study, Taiwan

This was a longitudinal double-blind nutrition intervention of rural women at risk nutritionally in an economically depressed area of west-central Taiwan (ADAIR, 1984; ADAIR and POLLITT, 1985). After the birth of a first child, women were randomly assigned to a nutrient-rich dietary supplement group (A) or a placebo group (B) for the lactation period, the gestation period of the subsequent pregnancy and its lactation period. The supplements were handed out twice daily by nurses who monitored intakes. Both groups received a multivitamin and mineral tablet daily and were provided with medical care. The outcome variables assessed included infant birth measurements, postnatal physical growth, motor and mental development, morbidity, and maternal weight and skinfold changes during pregnancy and lactation.

Energy intakes during lactation were significantly different in the two groups (5 and 7.5 MJ/d) but no significant effects were found in maternal weight, weight gain and skinfold thicknesses (ADAIR, 1984). Indeed, few A-B differences in mean values of the outcome variables were found except in some subgroups. Male infants born after a supplemented pregnancy weighed more at birth than brothers born earlier. Sibling correlations were lower in the supplemented group, suggesting that maternal supplementation affected the components of variation in infant anthropometry more than the means (MUELLER and POLLITT, 1982), and that there are differential risk and probability of response in populations (ADAIR and POLLITT, 1985). Important mediators of supplement effects included maternal body size (greater weight gain in mothers with lower weight-for-height), sex of offspring (males being more susceptible to supplementation than females) and season of the year. There were no treatment group differences in mental scores of 8-month-old infants but motor development scores were marginally significantly different. Supplementation had no effect on the Stanford Binet IQ evaluation of 5-year-old children. Thus, supplementation had limited effects on the population as a whole despite the apparent marginal nutritional status.