We Are What We Eat
Reported September 07, 2009
(Ivanhoe Newswire) — A recent Swedish study may shed new light on the old adage, “You are what you eat.”
Researchers found that DNA isolated from the muscles of people with diabetes bears chemical marks not found in those who respond normally to rising blood sugar levels. The marks in question are found on a specific gene that controls the amount of fuel, in the form of glucose or lipids that cells burn. Those marks also show up in the skeletal muscle of people with prediabetes as well, suggesting that the DNA modification might be an early event in the development of the disease.
Changes that reprogram the gene’s activity without altering the underlying DNA sequence suggest that environmental factors—what we eat or how active we are—may influence our genes. The researchers show that the alteration of the gene known as PGC-1? occurs in isolated muscle fiber cells when they are exposed to an inflammatory factor or to free fatty acids.
“These changes take place when you expose muscle to systemic factors that mimic the diabetic condition,” Juleen Zierath of the Karolinska Institutet in Sweden was quoted as saying.
Such changes to the epigenetic imprint have been seen before, Romain Barrès, the study’s first author explained. For instance, chemical modification of genes is responsible for developmental changes that take place as cells differentiate in the maturation process. The changes revealed in this study, however, take place in fully mature cells.
“It’s a much more dynamic process than we thought,” Zierath said. “The genetic causes of diabetes are important, but this shows us that epigenetic changes, which take place on top of our genes, can alter our physiology in critical ways.”
Evidence that dietary factors might influence gene control in diabetes had been suggested previously by a generational study in humans, which showed that the nutritional status of the grandparent is closely linked to an increased risk of diabetes-associated mortality in their grandchildren.
While the researchers say they do not yet know whether these epigenetic changes are reversible, they do have evidence that they might be prevented.
In a broader sense, the discovery shows that we are not “victims of our genes,” Zierath added. “It’s exciting because there may be ways for us to lower disease risk if physical activity or other lifestyle factors can positively influence our epigenome and improve metabolism.”
SOURCE: Cell Metabolism, September 2009