Aluísio Jardim Dornellas de Barros
This issue of the Revista de Saúde Pública (Journal of Public Health), includes a supplement. Six of the articles in this issue make up a supplement on Brazilian dietary habits, based on a dietary survey, part of the Household Budget Survey (POF), periodically carried out by the IBGE (Instituto Brasileiro de Geografia e Estatística - Brazilian Institute of Geography and Statistics).
There is a long-standing association between the IBGE's regular surveys and research related to public health in Brazil, which intensified after 1998 with the health survey incorporated into the PNAD (Pesquisa Nacional por Amostra de Domicilios - National Household Survey). This was repeated in 2003 and 2008 and has now become an independent piece of research in its own right, in the form of a national health survey. However, the association between the IBGE's economic research and health questions is not just a springboard to independent research. The richness of data available in these surveys, especially the POF, which makes a detailed survey of household spending, and the PNAD, which collects data on household, personal, employment, income and migration characteristics, provide opportunities not to be missed. These surveys are based on large, nationally and regionally representative samples, which enable inferences which are almost impossible in independent epidemiological studies. The data are immediately and publicly available on the internet. It is almost surprising that a larger number of researchers are not publishing analyses based on this data.
This supplement presents items of research which explore the richness of the available data. Similar to other analyses based on surveys with complex samples, it is essential that the sample design is taken into account. In particular, when estimated quantities are not in line with proportions and means of the directly collected variables, the task becomes more complicated. The estimates of quantities of calories, nutrients or micronutrients consumed by each individual in the sample is performed using complex handling of the original data collected. Thus, estimating variability is no trivial matter and it is necessary to use resampling techniques. The authors of the supplement show their commitment to public health and to methodological quality by adapting and using sophisticated techniques for extracting the best estimates of the available data.
To conclude, I would like to emphasize the importance of the results presented and the challenges to be overcome in the area of diet and nutrition. The panorama presented in this collection is of inestimable value in understanding the Brazilian health situation, with immediate consequences for economic, agro-industry, food industry, health and environmental policies. On the other hand, the contrast between the evident progress of Brazil and Brazilians from a social and health point of view, and deficiencies in intake of micronutrients, emphasizes the need for a wider understanding of the dietary phenomenon, of the adaptive capacity of human beings and to overcome political strategies which limit themselves to prescribing nutrition and behavior. Human motivation is based on highly complex decisions which encompass health, economy, leisure, enjoyment, social and individual aspects. Behavioral interventions have been demonstrated to be, for the most part, frustrating from a public health point of view. The data presented in this supplement, addition to others, need to serve as the basis for innovative, creative and courageous interventions which can really mean a change in direction away from what has been observed in high-income countries and which seems to be the destiny here in Brazil - very high prevalence of excess weight and sedentary lifestyles.