Mild stunting is associated with higher susceptibility to the effects of high fat diets: studies in a shantytown population in São Paulo, Brazil.

Previous studies by our group and others have suggested that nutritional stunting may increase the risk of obesity. To investigate mechanisms that could explain a link between stunting and obesity, a 22-mo follow-up study was conducted in two groups of shantytowns school girls (7-11 y old) in São Paulo, Brazil. One group (n = 15) had mild stunting (defined using a cutoff of -1.4 Z-scores of height-for-age) but normal weight-for-height; the control group (n = 15) had normal weight and height. Similar energy intake, dietary macronutrient composition and energy expenditure were observed in the two groups. Both groups showed comparable levels of IGF-1 that were below the normal range. A significant and positive association between baseline IGF-1 and the change in height-for-age during follow-up was found in all subjects combined (P = 0.044). A significant association was found between the baseline percentage of dietary energy supplied by fat and the gain in weight-for-height during follow-up in girls with mild stunting (P = 0.048), but not in the nonstunted control girls (P = 0.245); however, the slopes of these relationships were not significantly different. This study raises the question of whether a diet high in fat may increase the susceptibility to excess body fat gain in children who are mildly stunted. Further studies are need to explore this issue and to examine the possible etiological role of low levels of IGF-1.