Unhealthy diet may permanently change immune system

Exposure to a Western diet high in refined sugars, salt and saturated fat can have a permanent impact on the body’s immune system even if the diet is later changed, new research published in Cell suggests.

Lead researcher Eicke Latz, MD, PhD, said the Western diet triggers the NLRP3 inflammasome to activate the body’s immune system, similar to the way it responds to a bacterial infection.

“It has only recently been discovered that the innate immune system has a memory,” Latz, the founder and director of the Institute of Innate Immunity at the University of Bonn, Germany, said in a press release.

“After an infection, the body's defenses remain in a hyperactive, alarmed state, so that it can respond more quickly to a new attack. Our team of researchers discovered that the Western diet has a similar impact, and, therefore, these findings have enormous relevance to society and potential therapeutic implications.”

Latz and colleagues studied three groups of mice: one group given a standard chow diet, another fed a Western diet and a third fed a Western diet before switching back to standard chow. Compared to the mice on standard chow, the ones eating the high-calorie diet developed widespread inflammation throughout the body.

The ones who started on the Western diet and then switched back saw inflammation decrease, but the immune cells within their bone marrow remained altered—likely as a result of epigenetic reprogramming triggered by the Western diet, according to the press release.

Latz et al. also studied mice lacking the NLRP3 protein and found they didn’t show the same type of inflammation in response to the dietary programs. They said therapies that inhibit NLRP3 activity could ultimately slow the development of cardiovascular and metabolic diseases.