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Human beings are able to adapt genetically to their environment in order to survive. It is one of the fundamental principles of human evolution. However, new implications are gradually being revealed by science. For example, a mother’s diet during foetal development, as well as a child’s feeding when very young, is proving to have genetic consequences that have until now been little known about. These new data must have an impact on programmes to combat malnutrition.
Epigenetics: a new science?
Epigenetics is the study of the way the environment influences our genes.
“Our genetic heritage, made up of our DNA, is like our voice,” explains Professor Michel Roulet, medical advisor on health to Terre des hommes (Tdh). “It belongs to us and does not change. But external factors can influence its flow. It is these factors that makes up epigenetics.”
It seems that the diet of a mother during pregnancy, and a child’s during the first five years of life, is one of the factors that can influence an individual’s genetics. “This link is not new” Professor Roulet points out. “At the end of the Second World War, doctors started studying this phenomenon and the impact that famines had on the long-term health of children. They suggested that mothers who had suffered malnutrition during pregnancy gave birth to babies with growth retardation. But, more importantly, if these children quickly regained a normal diet in the first few years of life, their life expectancy was then reduced. In fact they became significantly vulnerable to a whole range of diseases: cardiovascular, hypertension, diabetes, etc. These doctors were initially treated as cranks and it took several decades before their conclusions started to be considered seriously. Today, the impact of diet is well recognised and there are countless publications on the subject. However, our understanding of the implications of this finding for our everyday life is still only in an early stage.”
A ticking time bomb
Growth retardation in a foetus or small child that has suffered malnutrition is part of the human capacity to adapt to an unfavourable environment. During the first years of life, our genes are malleable and can be shaped by external factors. “It is as if the child was programming itself to be poor” Professor Roulet explains. The child’s body adapts to a significant nutritional deficiency, and some organs develop better and faster than others to allow the child to survive. This change is then passed on for several generations. As a result one could find in a child’s genes the traces of a malnutrition suffered by his grandmother, for instance.
“Problems are magnified when the environment for which the child has been preparing changes suddenly” Professor Roulet continues. “The child’s body cannot keep up and the chances of developing a serious disease are multiplied. These predispositions are then passed on to the child’s children and grandchildren.”
We are all affected
This phenomenon does not only affect developing countries.
Any unbalanced diet during pregnancy or the first few years of life has the same consequences. Developed countries, which have seen an explosion in childhood obesity levels, or the populations of big cities in developing countries that have experienced a sudden improvement in living conditions are also affected. We are all equal in the face of this phenomenon.
However, this universal problem is likely to become subject to a two-tier development. All the food security agencies in developed countries are becoming drawn into the issue and launch researches on epigenetics. In the meantime, food and drug industries are rubbing their hands at the prospect of this new and potentially lucrative market. But how does this affect the fight against malnutrition?
The fight against malnutrition must adapt
There is almost no literature dealing with the link between epigenetics and the fight against malnutrition in small children. “However, these new developments should be taken into account at the highest levels,” declares Professor Roulet. “In projects to combat severe acute malnutrition, our number-one priority is usually to ensure that children gain weight as quickly as possible. But in so doing, we place children in an environment for which they are not prepared.”
Should we not intervene then? “Not at all: children suffering sever acute malnutrition are at risk of dying. We must intervene. But it is essential to bring about managed recovery. If we make children grow too rapidly, we save their lives in the short term, but we increase their risk of developing very serious diseases later on, and of passing on these predispositions to their own children. The speed of recovery must therefore be slowed down so that the environmental change is as gradual as possible. However, in the period in which children are regaining normal weight, their immune system is at its lowest and they risk developing potentially fatal infections. We have to find the best possible balance between these two opposing concerns, and the answer to this will probably remain unresolved for many years to come.”
Terre des hommes intervenes in the field of health and nutrition in 15 countries through 19 different projects. In 2010, more than 700,000 people benefited from activities implemented by Tdh.
