Improve your eating habits and will improve your health, common medical wisdom goes.

A new article in the Journal of Leukocyte Biology finds that we might as well keep eating poorly. They contend that the effects of poor eating habits persist after dietary habits are improved. In their mouse study, even after successful treatment of atherosclerosis (including lowering of blood cholesterol and a change in dietary habits) the effects of an unhealthy lifestyle still affected the way the immune system functions.

Epigenetics has become the catch-all excuse for lots of things and they say that poor eating habits alter the way genes express themselves, including genes related to immunity - yet somehow they alter easily the first time yet don't change back. This change in gene expression ultimately keeps the risk of cardiovascular disorders higher than it would be had there been no exposure to unhealthy foods in the first place.   

To researchers used two groups of mice that had an altered gene making them more susceptible to developing high blood cholesterol and atherosclerosis. The mice were either fed a high-fat, high-cholesterol diet (Western diet) or a normal diet (chow). After a long period of feeding, 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 chow diet for several months, after which the 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 also were examined. They found that DNA methylation, an epigenetic signature, in the bone marrow was different in mice that received bone marrow from the WTD-fed donors compared to the mice receiving bone marrow from chow-fed donors. These these mice also had large differences in their immune system and increased atherosclerosis.  

"We've long known that lifestyle and nutrition could affect immune system function," said John Wherry, Ph.D., 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."

So don't eat cheeseburgers. But if you do, you might as well stick with them.