Decreasing Obesity-Linked Inflammation with Glutamine

Glutamine could help people with obesity reduce inflammation of fat tissue and reduce fat mass, according to a new study. Additionally, glutamine levels can alter gene expression in several different cell types. The study is published in the journal Cell Metabolism.

In the current study, the researchers examined how the metabolic processes differed in fat tissue collected from the abdomen of 52 obese and 29 non-obese women. When comparing the two groups, they noticed a large difference in glutamine levels. People with obesity had, on average, lower levels of glutamine in their fat tissue than normal-weight people. Lower glutamine levels were also associated with larger fat cell size and higher body fat percentage independently of body mass index (BMI).

“Our results suggest that treatment with glutamine could be of value against obesity and insulin resistance,” says senior author Mikael Ryden of the Karolinska Institutet. “We know, however, that glutamine is also important for cell division and the metabolism of cancer, and therefore, more research on possible long-term side effects is needed before glutamine may be recommended as a dietary supplement to help treat obesity and its complications.”

The researchers also showed through a combination of animal and cell analyses that glutamine levels influenced the expression of different genes; low glutamine levels induced an increase in the expression of pro-inflammatory genes in the fat tissue. Obese mice injected with glutamine for two weeks had less fat tissue inflammation than mice that received a control saline solution. Their body fat mass, fat cell volume, and blood glucose levels were also reduced. In an analysis of cultured human fat cells, the expression of pro-inflammatory genes and the lipid content were attenuated after incubation with increasing concentrations of glutamine.

The researchers also studied in detail what happens inside the fat cell when glutamine levels are altered. They found that glutamine impacts a mechanism called O-GlcNAcylation that can control epigenetic changes. People with obesity had higher levels of O-GlcNAcylation in their fat tissue while mice and human cells treated with glutamine had lower levels of O-GlcNAcylation in the cell nucleus.

“Our study shows that glutamine is anti-inflammatory in the fat tissue by changing the gene expression in several different cell types,” Ryden says. “This means that a lack of glutamine, which may occur during long-term obesity, could lead to epigenetic changes that fuel inflammation in the body.”

Further research is needed to fully understand which genes and cellular processes are affected the most.