Onset and evolution of stunting in infants and children. Examples from the Human Nutrition Collaborative Research Support Program. Kenya and Egypt studies

Abstract

The etiology of the early onset of stunting is diverse among populations of varying biological, environmental and cultural circumstances. This is exemplified within the Nutrition CRSP project, which took place in three different populations and ecological conditions. Within each study area a different mix and varying proportions of causative factors were identified. At least in Kenya, and probably in Mexico, the problem has its antecedents in prepregnancy and pregnancy. Powerful determinants of the infants' size at birth and during the first 6 months of life are maternal size upon entry into pregnancy, and weight and fat gain during pregnancy and lactation. In all three countries a low pregnancy weight gain was observed. Notably in Kenya, where the energy intake of the mother decreases progressively throughout pregnancy, not only do mothers gain only half as much as European or North American women, but they even lose weight and fat in the last month of pregnancy, and some mothers gain no weight or lose weight during the whole of pregnancy. Mothers in Kenya start lactation with relatively poor fat stores. Although their energy intake increases somewhat during lactation, preliminary estimates suggest that these increases may be insufficient to maintain their bodily integrity, to carry out their normal tasks of daily living, and to produce a sufficient amount of milk for optimal infant growth. In addition to an energy deficit, diet quality is a problem, particularly in Kenya and Mexico and less so in Egypt. Intakes of animal products and animal protein are very low. Zinc and iron intakes are not only low, but the bioavailability of these nutrients is poor because of the high phytate, fiber and tea content of the diet. Also vitamin B12 intake is extremely low, and at least mild-to-moderate iodine deficiency (IDD) is present in Kenya. The above micronutrients have been demonstrated to affect the linear growth of the Kenyan children, even after confounding factors have been controlled. The early use of supplemental feeding in Kenya is a double-edged sword. On the one hand, there is a slight increase in febrile illness and possible displacement of breast milk intake in the supplemented infants, although mothers do not decrease breast feeding frequency and duration. On the other hand, even the modest amounts of available zinc and B12 in supplemental foods appear to have a positive effect on linear growth.(ABSTRACT TRUNCATED AT 400 WORDS)

PIP: Findings from the Nutritional Collaborative Research Support Program (CRSP) in Kenya, Mexico, and Egypt demonstrate how the etiology of the early onset of stunting varies among populations of varying biological, environmental, and cultural circumstances. In Kenya, and probably Mexico, the problem has its antecedents in prepregnancy and pregnancy. Maternal size upon entry into pregnancy and weight and fat gain during pregnancy and lactation are powerful determinants of an infant's size at birth and during the first six months of life. Low pregnancy weight gain was observed in all three countries. Mothers in Kenya even lose weight and fat in the last month of pregnancy, with some gaining no weight or losing weight during the whole of pregnancy. Mothers in Kenya begin lactation with relatively poor fat stores, thus possibly unable to produce a sufficient amount of milk for optimal infant growth even though their energy intake increases somewhat during lactation. Intakes of animal products and animal protein are also low especially in Kenya and Mexico. Intakes of zinc, iron, vitamin B12, and iodine are low, and have been shown to affect the linear growth of the Kenyan children even after controlling for confounding factors. The early use of supplemental feeding in Kenya positively affects linear growth, yet increases febrile illness and possibly displaces breast milk intake in supplemented infants. Morbidity negatively affects attained length in six-month old infants and the rate of linear growth, while cultural patterns of child rearing also appear important for growth. A major deceleration of growth occurs in the first six months of life; from 18 months onward the quantity and quality of diet and environmental factors do not permit catch-up to the normal or near normal centiles observed in newborns.