Impact of nutrition on mental health and the role of different dietary approaches to improve depression and mood disorders: a systematic review

Depression is a mood disorder with a negative impact at the individual and community levels. Depression has multifactorial causes, both biological and psychosocial factors like genetics, age, gender, but and also the environment. Diet may be considered a modifiable risk for depression because it can increase or decrease the incidence of depression, depending on the type of foods eaten. Nutritional intervention can affect depressive symptomology throughby impacting the gut microbiota and the effects of weight loss. In general, increasing fruits and vegetables and reducing junk foods reduced inflammation, mitochondrial dysfunction and oxidative stress which are linked to reduced depression. Different nutritional approaches can have different effects in worsening or bettering depression symptoms. Major depression can be worsened by the disruption of the gut microbiota. The gut-brain axis is a bidirectional pathway that transfer signals between the gut and the brain. Gut microbiota influences the brain indirectly and directly, having consequences in the mood disorders. In this thesis work, the aim is to understand firstly the impact of nutrition and the microbiota-gut-brain axis on depression. Further will be analyzed different nutritional approaches to understand how they impact on depression.