New research by Lund Universities Diabetes Centre, has found that gene expression that affects fat storage in the body changes with even small amounts of exercise.
“Our study shows the positive effects of exercise, because the epigenetic pattern of genes that affect fat storage in the body changes,” says Charlotte Ling, Associate Professor at Lund University Diabetes Centre.
The cells of the body contain DNA, which contains genes. We inherit our genes and they cannot be changed. The genes, however, have ‘methyl groups’ attached which affect what is known as ‘gene expression’ — whether the genes are activated or deactivated. The methyl groups can be influenced in various ways, through exercise, diet and lifestyle, in a process known as ‘DNA methylation’ and the overall process is called epigenetics.
In this study, the researchers examined what occurred to the methyl groups in the fat cells of 23 slightly overweight, healthy men aged around 35 who had not previously engaged in any physical activity, when they regularly attended spinning and aerobics classes over a six-month period.
“They were supposed to attend three sessions a week, but they went on average 1.8 times,” says Tina Rönn, Associate Researcher at Lund University.
Using technology that analyses 480 000 positions throughout the genome, they could see that epigenetic changes had taken place in 7,000 genes (an individual has 20-25 000 genes). They then went on to look specifically at the methylation in genes linked to type 2 diabetes and obesity.
“We found changes in those genes too, which suggests that altered DNA methylation as a result of physical activity could be one of the mechanisms of how these genes affect the risk of disease,” says Tina Rönn, adding that this has never before been studied in fat cells and that they now have a map of the DNA methylome in fat.
A prior study in 2012 determined that Caffeine consumption had the same effect on gene expression as exercise.
“Our muscles are really plastic,” says Juleen Zierath of Karolinska Institutet in Sweden. “We often say “You are what you eat.” Well, muscle adapts to what you do. If you don’t use it, you lose it, and this is one of the mechanisms that allows that to happen.”
The DNA changes in question are known as epigenetic modifications and involve the gain or loss of chemical marks on DNA over and above the familiar sequence of As, Gs, Ts, and Cs. The new study shows that the DNA within skeletal muscle taken from people after a burst of exercise bears fewer chemical marks (specifically methyl groups) than it did before exercise. Those changes take place in stretches of DNA that are involved in turning “on” genes important for muscles’ adaptation to exercise.
When the researchers made muscles contract in lab dishes, they saw a similar loss of DNA methyl groups. Exposure of isolated muscle to caffeine had the same effect.
Zierath explained that caffeine does mimic the muscle contraction that comes with exercise in other ways, too. She doesn’t necessarily recommend anyone drink a cup of joe in place of exercise. It’s nevertheless tempting to think that athletes who enjoy a coffee with their workout might just be on to something.
Broadly speaking, the findings offer more evidence that our genomes are much more dynamic than they are often given credit for. Epigenetic modifications that turn genes on and back off again can be incredibly flexible events. They allow the DNA in our cells to adjust as the environment shifts.
“Exercise is medicine,” Zierath says, and it seems the means to alter our genomes for better health may be only a jog away. And for those who can’t exercise, the new findings might point the way to medicines (caffeinated ones, perhaps?) with similar benefits.
Romain Barrès, Jie Yan, Brendan Egan, Jonas Thue Treebak, Morten Rasmussen, Tomas Fritz, Kenneth Caidahl, Anna Krook, Donal J. O’Gorman, Juleen R. Zierath. Acute Exercise Remodels Promoter Methylation in Human Skeletal Muscle. Cell Metabolism, 2012; 15 (3): 405 DOI: 10.1016/j.cmet.2012.01.001
Tina Rönn, Petr Volkov, Cajsa Davegårdh, Tasnim Dayeh, Elin Hall, Anders H. Olsson, Emma Nilsson, Åsa Tornberg, Marloes Dekker Nitert, Karl-Fredrik Eriksson, Helena A. Jones, Leif Groop, Charlotte Ling. A Six Months Exercise Intervention Influences the Genome-wide DNA Methylation Pattern in Human Adipose Tissue. PLoS Genetics, 2013; 9 (6): e1003572 DOI: 10.1371/journal.pgen.1003572