Inflammation is a problem that if left unchecked could trigger any number of chronic diseases. The simple technique of fasting has been shown to fight inflammation and researchers from the University of Cambridge believe they now know why.
Researchers described in a report in the journal Cell Reports how fasting raises a chemical in the blood called arachidonic acid, which has the ability to block inflammation.
Inflammation is the body’s natural response to infection or injury. But that’s different from chronic inflammation which raises the risk of a variety of diseases including diabetes and heart disease. That can be attributed in part to the high-calorie Western diet many Americans enjoy.
In addition to a response to injury, inflammation can also be triggered by other mechanisms. Inflammasome is like an alarm in the body that triggers inflammation as a result of injury, but it can also destroy unwanted cells and the release of the contents of those cells can trigger inflammation.
"We're very interested in trying to understand the causes of chronic inflammation in the context of many human diseases, and in particular the role of the inflammasome," Professor Clare Bryant from the Department of Medicine at the University of Cambridge said. "What's become apparent over recent years is that one inflammasome in particular—the NLRP3 inflammasome—is very important in a number of major diseases such as obesity and atherosclerosis, but also in diseases like Alzheimer's and Parkinson's disease, many of the diseases of older age people, particularly in the Western world."
To understand how fasting can impact inflammation, Bryant and others from Cambridge worked with the National Institutes for Health in the U.S. to study blood samples from a group of 21 volunteers. The study subjects ate a 500-kcal meal and then fasted 24 hours before having another 500-kcal meal.
The scientists found the act or restricting calorie intake increased levels of arachidonic acid. That lipid and others play an important role in the body such as storing energy or transmitting information between cells. When the volunteers ate a meal again after fasting, their levels of arachidonic acid dropped.
Scientists studied what effect arachidonic acid had on immune cells in a laboratory setting and realized it has the ability to reduce the activity of the NLRP3 inflammasome. That came as a surprise to researchers as it was thought arachidonic acid was linked to increased levels of inflammation, not decreased.
"This provides a potential explanation for how changing our diet—in particular by fasting—protects us from inflammation, especially the damaging form that underpins many diseases related to a Western high-calorie diet," Bryant said. "It's too early to say whether fasting protects against diseases like Alzheimer's and Parkinson's disease, as the effects of arachidonic acid are only short-lived, but our work adds to a growing amount of scientific literature that points to the health benefits of calorie restriction. It suggests that regular fasting over a long period could help reduce the chronic inflammation we associate with these conditions. It's certainly an attractive idea."