How Blood Fat Causes Harmful Inflammation

In a study published today in Nature Immunology, Saarland University researchers were able to show how fat molecules in the blood interact with body cells, mobilizing the immune system to damaging effect.

“Our work has involved studying a special group of lipids, the triglycerides,” says senior author Timo Speer of Saarland University. “We’ve been able to show that when these naturally occurring fats are present at elevated concentrations, they can alter our defense cells in such a way that the body reacts as if responding to a bacterial infection. This leads to inflammation, which, if it becomes chronic, can damage the kidneys or cause atherosclerosis—the narrowing of arteries due to a buildup of deposits on the inner arterial wall. And atherosclerosis is one of the main causes of heart attacks and strokes.”

The large-scale study was able to demonstrate that patients with elevated levels of triglycerides in their blood had a significantly higher mortality rate than comparison groups with a similar health history. “Put another way, we can now say that adopting a low-fat diet can significantly extend the life expectancy of high-risk patients, such as those with diabetes or those whose blood pressure is too high,” Speer says.

Blood triglyceride levels rise substantially in people who eat a high-fat diet. “As a result of biochemical changes, the triglycerides develop toxic properties that activate the body’s innate immune system,” Speer explains. “This initiates a series of self-destructive processes including those in which the walls of the arteries are attacked and the blood vessels become occluded, reducing blood flow.”

The study has established a definitive link between the chronic inflammation triggered by an elevated triglyceride concentration in the blood and secondary diseases such as kidney failure or heart attack. “We hope that our results will help in developing new strategies for treating and preventing these life-threatening diseases,” Speer says.