High-fat diet could promote depression, study says
Scientists from the University of Glasgow in Scotland demonstrated the links between the consumption of diets high in saturated fats that lead to obesity and development of depression phenotypes, according to a new study published recently in the journal Translational Psychiatry.
The researchers also found that by decreasing the expression of a specific enzyme called phosphodiesterase, symptoms of obesity-linked depression can be reduced.
In the findings, shown in mouse models, researchers were able to see that saturated fatty acids were entering the brain via the bloodstream and thereafter accumulate and affect crucial brain signals related to depression. Mice fed a fat-dense diet, made up of 60 percent saturated and unsaturated fats, were shown to have an influx of dietary fatty acids in the hypothalamus region of the brain, an area related to the metabolic system and known to be linked with depression. These fatty acids were then able to directly affect the key signaling pathways responsible for the development of depression.
The relationship between obesity and depression is known to be complicated, researchers said in a statement released by the university, with patients with obesity less likely to respond well to common antidepressant medication. Patients with obesity show a substantially slower response to antidepressant treatment, with less overall improvements, researchers said.
Either dietary or genetically induced obesity in mice lead to depression phenotype, and this phenomenon occurred via the disruption of the cAMP/PKA signaling pathway, researchers said. In addition, the researchers found that the consumption of a fat-dense diet led to an influx of dietary fatty acids specifically in the hypothalamus. These fatty acids could then directly modulate the PKA signaling pathway responsible for the development of depression. These findings suggest that the influx of saturated fatty acids due to the consumption of a high fat diet can alter the cAMP/PKA signaling process, which results in the development of depression phenotype.
The findings, researchers said, may now influence new targets for antidepressant medications that may be more suitable for overweight and obese individuals.