A new study has revealed that people conceived during the famine of the second world war still show signs of malnourishment in later life. The research is part of an investigation into how significantly environmental factors affect our genetic make-up and how healthy we become.
In one study, survivors born during the Dutch “Hunger Winter”, which occurred at the end of the second world war, still portray lasting effects of malnutrition in their genes, sixty years later.
Experts report that environmental influences can have a profound effect on the human genome - especially in babies and children, as it has an ability to “remember”, thus altering DNA in some cases and even causing defects to be inherited.
These epigenetic effects are now regarded as having an increasing result on the way in which our DNA affects our overall health. Nature as well as nurture in fact combine to determine growth, development, metabolism and immunity.
Between 1944 and 1945 the Germans stopped food from reaching citizens in the Netherlands, which is now known as the Hunger Winter. Epigenetic specialists are fascinated by the long term effects this had on those experiencing the famine and thus a natural study has been provided.
Research in the past have proven that mothers who were pregnant during the famine, bore children more susceptible to heart problems, obesity and diabetes. In addition, it was discovered that they had a tendency of giving birth to underweight babies.
As a result of these findings, many scientists believe that epigenetics were responsible. The theory was that as a result of not having enough nutrients in the womb to develop sufficiently, genes were altered in order to change the metabolism, so that it could survive at an optimum with what few nutrients it had.
A mechanism like this could have developed because the uterine environment was often a reliable guide to the conditions that would take precedence once a child was born, so encouraging it to become thrifty with energy by only using it as and when would result in a better chance of survival.
This theory now receives backing from this innovative new reseach, which was led by Bastiaan Heijmans, of Leiden University in the Netherlands. The full results are published in the journal Proceedings of the National Academy of Sciences.
The leading system of epigenetics is a process called methylation, which involves chemical groups being added to DNA to alter its function. Dr Heijmans’s team studied this in those born during the Hunger Winter, and their brothers and sisters born when the famine was over.
Despite the fact that these people are now in the latter stages of their lives well into their sixties, the lasting effects of the famine can still be observed in their genomes, via the methylation patterns on a gene called insulin-like growth factor 2 or IGF2.
Those who experienced the famine withing the first ten weeks after their conception had considerably less methylation of the IGF2 gene than their siblings of the same sex. In contrast, no effects were reported in people who were 10 weeks away from birth when the famine began.
These results strongly suggest the significance of environmental factors and their effect on the genome and related health throughout life, during prenatal development.
Dr Heijmans said: “Our study provides the first evidence that transient environmental conditions early in human gestation can be recorded as persistent changes in epigenetic information.
“Understanding how epigenetic control depends on early exposure may shed light on the link between development and health over the lifespan and ultimately suggest new ways to prevent human disease.”
