Improving your eating habits should improve your health, but poor eating habits can still be made after good dietary habits have begun. A report detailing the findings appears in the November 2014 issue of Journal of Leukocyte Biology.
To prove this, researchers used mice to demonstrate that even after treating atherosclerosis, lowering blood cholesterol and changing dietary habits, the effects of an unhealthy lifestyle still affected the way the immune system functioned. The function change occurred mainly because poor eating habits alter the way genes express themselves including genes related to immunity. This gene expression change known as epigenetics keeps the risk of cardiovascular disorders higher than if there had been no exposure to unhealthy foods at all.
For this study and discovery the scientists used two groups of mice with an altered gene that made them more susceptible to developing high blood cholesterol and atherosclerosis. They were fed either a Western-type diet that is high in fat and high in cholesterol or a normal diet. Following a long feeding period, bone marrow was isolated from the mice and transplanted into mice with a similar genetic background that had their own bone marrow destroyed. The recipient mice were left on the normal diet for several months and following this their development of atherosclerosis in the heart was measured.
The number and status of immune cells throughout the body and epigenetic markings on the DNA in the bone marrow were also examined. They discovered that DNA methylation an epigenetic signature in the bone marrow was different in mice that received bone marrow from the Western-type diet-fed donors compared to the mice receiving bone marrow from the normal diet-fed donors. These mice also had large differences in their immune system and increased atherosclerosis.
I hope that this study demonstrates the importance of diet-induced changes in the epigenome and encourages further research into the interaction between dietary patterns, DNA methylation and disease," said Erik van Kampen, Division of Biopharmaceutics at the Leiden Academic Centre for Drug Research at Leiden University in Leiden, The Netherlands.
We've long known that lifestyle and nutrition could affect immune system function," said John Wherry, Ph.D., and Deputy Editor of the Journal of Leukocyte Biology. "The ability of nutritional history to have durable affects on immune cells demonstrated in this new report could have profound implications for treatment of diseases with immune underpinnings. The length of such effects will be critical to determine and it will be interesting to examine the effects of drugs that can modify epigenetics."