Kamis, 26 Januari 2012

Poverty and The Nutrition Transition

Data from the past decade and projections for the next 20 years (Murray and Lopez, 1996) indicate a continuing rise in the contribution of no communicable diseases to mortality rates in developing countries, where a large proportion of the global poor lives. But within the developing world population, there are clear differences between the upper and lower socioeconomic groups. Among the poorest 20%, communicable diseases still account for about 60% of deaths, whereas they account for only 8% among the richest 20% (Gwatkin et al., 1999). A confounding factor may be the difference in population patterns between richer and poorer countries, with the latter having as much as twice the number of under-15 population, which has higher rates of communicable disease than older groups. Although it is likely that the younger population of the developing world still faces infectious diseases as a major threat to health and quality of life, the burden of no communicable diseases continues to mount for the older poor. As economic status and education improve, populations in developing countries around the world respond quite consistently by demanding more animal protein in their diet. In many cases, this demand is justified, since their typical diet is usually low in zinc, iron, selenium, retinol, and other essential nutrients found primarily in animal sources. However, increases in the animal protein content of diets almost invariably increase the content in saturated fats, which is undesirable. The role of genes in the human adaptation to rapid environmental changes has been postulated for many decades, but only with advances in molecular genetics can we identify with some clarity the interactions between genes and environmental components such as diet. Populations living under subsistence conditions are forced to maximize their potential for survival, and it is likely that specific sets of genes are activated to facilitate this process. Thus, rapid changes in the environment, even when positive (e.g., more food available) will tend to perturb that precarious equilibrium between the genome and the environment. If the genetic makeup of some individuals does not allow for a rapid shift to the new environmental conditions, adverse health effects may result. This hypothetical but probable phenomenon can be seen within the same generation, i.e., children who were malnourished early in life becoming more prone to obesity as adults. The particular genetic makeup of populations in developing countries, of which we know so little, adds a unique and important element to the impact of the nutrition transition on health. Individuals “miss-adapted” to the new dietary conditions may have a higher risk of adverse health effects.


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