The Consequences of Poor Eating Habits Persist Even after Diet is Improved

New research published in the Journal of Leukocyte Biology suggests that these changes to the behaviour of the immune system are persistent and can continue even after your diet has improved.[1] It is fairly universally understood that improving your food behaviour and choice will most likely improve your health. However, less well understood or known is that the effects of poor eating habits persist long after dietary habits are improved. In a new report appearing in the November 2014 issue of the Journal of Leukocyte Biology, scientists use mice to show that even after successful treatment of atherosclerosis (including lowering of blood cholesterol and a change in dietary habits) the effects of an unhealthy lifestyle still impact upon the way the immune system functions. This change in function occurs largely because poor eating habits alter the way genes express themselves, including genes related to immunity which make up the largest collection of specific genes in the human structure. This change in gene expression (epigenetics) ultimately maintains the risk of cardiovascular disorders at a level far higher than it would be had there been no exposure to unhealthy foods in the first place.

Erik Van Kampen, one of the researchers involved in the study states-

“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.”

To establish this mechanism, scientists used two groups of mice that had an altered gene making them more susceptible to developing high blood cholesterol and atherosclerosis. These mice were either fed a high-fat, high-cholesterol diet (Western-type diet, WTD) or a normal diet (chow – albeit there are numerous variations on this).

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. Furthermore, these mice had large differences in their immune system and increased atherosclerosis.

John Wherry, Ph.D., Deputy Editor of the Journal of Leukocyte Biology stated

 “We’ve long known that lifestyle and nutrition could affect immune system function. The ability of nutritional history to have durable effects on immune cells demonstrated in this new report could have profound implications for treatment of diseases with immune underpinnings.”

Comment

The implication for clinical care is that epigenetic modifications or reversals of nutrition related events may need a more prolonged intervention to rectify risk factors, that time period is not yet known and will likely also be age related but will present some interesting analysis in the years to come.

Reference