How Insulin Influences Our Brain And Feelings Of Hunger

Researchers have learned more about insulin’s function in the brain, including its influence over our feelings of hunger.

Earlier studies revealed that insulin acts on the brain’s hypothalamus, but new evidence shows it is active in others brain areas as well. To discover this, researchers gave 25 lean, 10 overweight, and 12 obese young adults either insulin via a nasal spray, or a placebo nasal spray. Then, the participants’ brain activity was recorded using imaging technology.

In those receiving the insulin, connectivity in the prefrontal regions of the default-mode network (DMN) was improved. The DMN areas are activated when people are at rest, daydreaming, or making plans. Additionally, the connections between the DMN, hippocampus, and hypothalamus were strengthened. The hypothalamus is a regulatory center for hormonal activity, blood pressure, water-saline balance, and it helps regulate food intake.

The study’s insulin-induced brain changes also affected the relationship between adiposity (stored body fat) and the hunger sensation. Normally, people with an abundance of abdominal fat have heightened feelings of hunger. However, with an insulin enhanced DMN-hippocampus connection, the link between adiposity and hunger was suppressed. So, study participants experienced less hunger after inhaling the insulin spray.

The investigators also noted that insulin in the brain increases the effectiveness of insulin outside the brain. The study participants with DMN connectivity enhanced by insulin also had greater insulin sensitivity in their bodies.

Findings from this study were published in Scientific Reports, a Nature research journal. The study was performed through the Institute for Diabetes Research and Metabolic Diseases of Helmholtz Zentrum München at the University of Tübingen.

Source: DZD
Photo credit: Amen Clinics