Research in nutritional psychiatry shows that food directly affects brain structure, function, and mood. For example, diets high in vitamins, minerals, antioxidants, omega‑3s, and fiber—such as the Mediterranean diet—reduce inflammation and support production of neurotransmitters like serotonin and dopamine 

A landmark randomized controlled trial (SMILES trial) found that switching from a typical Western diet to a Mediterranean-style diet significantly alleviated symptoms of major depression and improved happiness

Another important mechanism is the gut–brain axis: the gut microbiome helps regulate mood by producing neurotransmitters and reducing inflammation, with untreated imbalances linked to anxiety and depression