Dietary fats entering the brain may explain the link between obesity and depression

Obesity and depression have long been linked, with previous clinical studies showing an association between these two conditions. However, until now, the mechanisms of obesity on depression and vice versa have not been completely understood.

In a new study conducted by the University of Glasgow in collaboration with the Gladstone institutes and published today in Translational psychiatry, scientists were able to demonstrate the links between eating saturated fat foods leading to obesity and developing depressive phenotypes. They also found that by decreasing the expression of a specific enzyme called phosphodiesterase, the symptoms of depression related to obesity can be reduced.

New discoveries, shown in mouse models, have allowed researchers to see that saturated fatty acids enter the brain through the blood, then accumulate and affect essential cerebral signals related to depression. Mice fed a high-fat diet (composed of 60% saturated and unsaturated fats) have been found to have an influx of dietary fatty acids in the region of the brain's hypothalamus, a region linked to the system. metabolic and known to be related to depression. . These fatty acids could then directly affect the main signaling pathways responsible for the development of depression.

The relationship between obesity and depression is known to be complicated, with obese patients less likely to respond well to conventional antidepressants. Indeed, obese patients have a significantly slower response to antidepressant treatment, with less overall improvements.

The researchers in this study believe that their breakthrough discoveries may now be influencing new targets for antidepressants, which may be more appropriate for overweight and obese individuals.

Professor George Baillie, lead author of the University of Glasgow study, said, "This is the first time anyone observes the direct effects of a high-fat diet on brain-related signaling areas. This research could begin to explain how and why obesity is related to depression and how we can potentially better treat patients with these conditions.

"We often use fatty foods to comfort us because they taste good, but in the long run it will negatively affect your mood, of course, if you feel bad, so that you feel better, you could offer yourself some foods. more fat, which would then consolidate the negative feelings.

"We all know that a reduction in the consumption of fatty foods can have many beneficial effects on health, but our research suggests that it also promotes a happier disposition. Types of fats, such as palmitic acid, likely to enter the brain, key regions and signaling will give people more information on how their diet can potentially affect their mental health . "

In this study, researchers found that food or genetically induced obesity in mice resulted in a depression phenotype and that this phenomenon occurred via disruption of the cAMP / PKA signaling pathway. In addition, they found that eating a high-fat diet resulted in an influx of dietary fatty acids, particularly in the hypothalamus. These fatty acids could then directly modulate the signaling pathway of the PKA responsible for the development of depression. These results suggest that the influx of saturated fatty acids due to the consumption of a high-fat diet can alter the cAMP / PKA signaling process, resulting in the development of a phenotype of depression.