Poor eating habits have long-term effects on immune system

Effects of poor eating habits persist long after diet is improved, a new study has found.
Scientists in experiments on mice found 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 affect 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.
This change in gene expression (epigenetics) ultimately keeps the risk of cardiovascular disorders higher than it would be had there been no exposure to unhealthy foods in the first place.

"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, a researcher involved in the work from Leiden University in Leiden, The Netherlands.
To make their discovery, 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).
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.
The researchers 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.
The study was published in the Journal of Leukocyte Biology.