At one time experts believed genes were static unless a gene sequence was altered by a mutation. Now a whole new field has sprung up around the idea that gene expression can be altered by environmental exposures and lifestyle. In other words, even if you inherited genes that predispose you to being obese, you may or may not express those genes based on your environment, diet and exercise habits. So the genetic sequences your parents gave you aren’t necessarily destiny.
Epigenetics, Exercise, and Fat Cells
Researchers from Lund University did an interesting experiment. They asked 23 healthy, but overweight, men to take a spin or aerobics class three times a week while continuing to eat their current diet. The men “cheated” a bit and most only attended a little more than half of the scheduled classes.
In this study, the researchers were interested in how exercise would affect fat cells, particularly the genes that encode for fat cell activity. They used special technology to sequence genes, or DNA, inside fat cells. Here’s the shocker. After six months of modest amounts of exercise – remember, the men cheated – a third of the men’s genes showed changes in gene expression. More specifically, they found changes in methyl groups, molecules that affect whether or not a gene is expressed or remains silent.
For further confirmation, they deactivated some of the genes altered by exercise. Low and behold, it changed the way fat cells store fat. In addition, they found epigenetic changes affecting genes linked with obesity and obesity-related problems like type 2-diabetes. So working out may do more than increase fat breakdown, it may alter how genes are expressed. Such is the power of a good workout!
Interestingly, the men in this study did a limited amount of exercise to get these benefits. What would be the impact of more frequent exercise or workouts that are more intense? Keep in mind that this was a small study but it confirms prior epigenetic research showing that lifestyle factors affect gene methylation and whether or not genes exert their influence.
Exercise May Reduce the Risk of Other Problems Related to Obesity
In this study, researchers also found changes in genes associated with a higher risk for type 2-diabetes. Other earlier research shows that there are multiple sets of genes that affect type 2-diabetes risk and insulin resistance and exposure to certain nutrients can modify these genes through methylation (adding a methyl group) or de-methylation so they’re more or less likely to be expressed. When a gene is modified by adding a methyl group, it essentially “silences” the gene so it isn’t expressed. In contrast, if you remove a methyl group from a sequence of genes, it turns on the expression of previously silent genes.
The impact of epigenetics may be long-lasting. For example, there’s evidence to suggest that the nutrition a fetus gets from its mom during pregnancy is linked with epigenetic changes that impact their risk of obesity when it becomes an adult. It’s also possible that a healthy lifestyle – good nutrition and exercise – may turn off the expression of genes you’d rather not have expressed.
Environmental exposures alter gene expression too. There’s evidence in mice that exposure to BPA, an ingredient in some plastic products, removes methyl groups from genes that linked with obesity, allowing them to be turned on. This may explain the recent link between BPA and obesity.
Unlike mutations that alter the sequence of a gene and change its basic structure, epigenetic cause gene modifications (methylation or de-methylation) that are reversible. This means you may not be “stuck” with bad genes. You can potentially silence those genes by eating a healthy diet, avoiding bad habits like smoking and working out. That’s reassuring to know if obesity or type 2 diabetes “runs in the family.”
The Bottom Line?
Although more research is needed, there’s evidence that exercise can alter fat cell genetics in a positive way. Combine an exercise plan with a healthy diet to help your genes “behave.” Now there’s another reason to work up a sweat – as if you needed one!
References:
PLoS Genetics, 2013; 9 (6): e1003572 DOI: 10.1371/journal.pgen.1003572.
Diabetes December 2009 vol. 58 no. 12 2718-2725.
Diabetes Forecast. “The Science of Epigenetics”
Proceedings of the National Academy of Sciences 104, 13056–13061 (2007) doi:10.1073/pnas.0703739104
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