Systemic inflammation may be due to a poor gut diet, study finds

A high fat diet in mice leads to a substantial increase in blood lipids linked to systemic inflammation, according to a recent study. Bacteria of the intestinal tract may play a role in disease-causing inflammation, scientists say. The study proposes that focusing on the mucus lining between the cells of the small intestine and gut bacteria could be the key to preventing systemic inflammation.

Those treated for HIV have continual low-grade inflammation in their small intestine, increasing the risk of heart attack or stroke. These individuals have also been found to have more inflammatory bacteria in their blood such as lipopolysaccharide, or LPS, which can accelerate the deterioration of the arteries after being exposed to continuous inflammation. 

Researchers at UCLA used mice treated with HIV to study this problem. Interestingly, by adding a tomato concentrate known as Tg6F to the mices’ diet, leaky gut symptoms improved significantly. Systemic inflammation in the mice was also greatly reduced, which could be in large part due to the peptide mimetic in Tg6F that mimics good cholesterol. To learn more, scientists fed half the mice a typical western diet high in fat, while the other half received a low-fat diet. 

The Significance of Diet on Gut Inflammation

By examining the dietary phospholipids, researchers were able to make some insights into how diet can cause inflammation. Oxidized phospholipids can cause an inflammatory response in the body. Researchers expected the western diet would contain high amounts of oxidized phospholipids, but the results showed the opposite. To their surprise, scientists discovered a lower amount of the dangerous phospholipids in the western diet, while the low-fat diet actually contained more.

“We studied the portion of the small intestine known as the jejunum because it is very actively involved in the uptake of dietary fats,” says Dr. Alan M. Fogelman, in a statement. Dr. Fogelman is chair of the department of medicine at the David Geffen School of Medicine at UCLA. A thin mucous layer helps protect the bacteria in the jejunum from interacting with its cells. Mice fed the high-fat diet had higher levels of oxidized phospholipids in their jejunum compared to mice fed a low-fat diet. 

Mice fed the western diet also had higher levels of LPS. To test whether western diet-mediated changes were a result of the oxidized phospholipids in the jejunum, oxidized lipids were added to the jejunum of mice on the low-fat diet. This resulted in changes in gene expression similar to mice who were fed the western diet.

Tg6F was again found to reduce levels of oxidized lipids, while also reducing the presence of LPS in the blood. It also prevented the formation of bacteria and LPS in jejunum mucus, which significantly reduced overall inflammation. The results suggest that targeting the mucus layer of the small intestine with peptide mimetics of the main protein in HDL could be the secret to preventing systemic inflammation. 

Find this study in the Journal Of Lipid Research.

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