The extra pounds gained over the holidays not only show on our hips, but also affect our DNA. This is the outcome of a major international study led by the Helmholtz Zentrum Muenchen, which shows that an increased body mass index (BMI) leads to epigenetic changes at almost 200 loci of the genome.
While our genes barely change over the course of our lives, our lifestyle can have a direct impact on their surroundings. Scientists speak here of the epigenome (from the Greek word epi meaning over, outside of, around) – so everything that happens on or around the genes. To date, scant research has been conducted into how the epigenome is altered by obesity. “This issue is particularly relevant because an estimated one and a half billion people around the world are overweight,” said the study’s lead author, Dr. Simone Wahl from the Research Unit of Molecular Epidemiology (AME) at the Helmholtz Zentrum Muenchen. “Especially considering that being overweight can have adverse effects and lead to diabetes as well as diseases of the cardiovascular and metabolic systems.”
World’s largest study on BMI and epigenetics
The international research team led by Dr. Christian Gieger and Dr. Harald Grallert from the Helmholtz Zentrum Muenchen therefore investigated possible links between body mass index (BMI) and epigenetic changes. Using the ever-improving technology at their disposal, they conducted the world’s largest study on this subject to date.
The scientists examined blood samples from more than 10,000 women and men from across Europe. Many of them were inhabitants of London of Indian descent – a group that the authors believe to be at high risk of obesity and metabolic diseases. In a first step with 5,387 samples – among others from the biobank of the Augsburg KORA study, the London LOLIPOP study and part of the Italian EPICOR study – the research team identified 207 gene loci that were epigenetically altered dependent on the BMI. Further studies and long-term observations moreover revealed that the changes were mostly a consequence of being overweight and not the cause.
Significant changes – also to the inflammatory genes
“In particular, significant changes were found in the expression of genes responsible for lipid metabolism and substrate transport, but inflammation-related gene loci were also affected,” explains group leader, Harald Grallert. The team was additionally able to use the data to identify epigenetic markers that could predict the risk of type 2 diabetes.
“Our results allow new insights into which signalling pathways are influenced by obesity,” said Dr. Christian Gieger, head of the biobank at the Helmholtz Zentrum Muenchen (HMGU Biobank), which belongs to the Joint Biobank Munich (JBM), as well as the Department of Molecular Epidemiology at the Helmholtz Zentrum Muenchen. “We hope that this will lead to new strategies for predicting and possibly preventing type 2 diabetes and other consequences of being overweight.” The researchers now wish to investigate how the individual epigenetic changes affect the expression of the underlying genes.
Source: Helmholtz Zentrum München, partner of the Joint Biobank München