Why Diet is The New Antidepressant on the Block – Diet and Depression
There are multiple theories for major depressive disorder (MDD) with no single mechanism likely to be responsible. This is because there are many different clinical variations with overlapping genetic, biochemical, and neurophysiological changes in the brain known to be implicated in MDD.
One prevalent theory is the monoamine oxidase (MAO) theory of depression, which states that there is a lack of monamine neurotransmitters such as serotonin and norepinephrine. This is evidenced by the inhibition of the MAO enzyme by monamine oxidase inhibitors that can help relieve depressive symptoms.
However, as previously stated, genetic factors, stress, psychosocial factors all play a role too. Recent evidence also suggests that nutritional factors also play a role in mental health. Observations show there is a relationship between unhealthy dietary patterns and poorer mental health. There is also likely to be a dietary influence on brain plasticity, gut microbiota, inflammatory processes, and oxidative stress.
Existing data suggests a causal relationship between diet quality and depression. Diets enriched in processed foods and sugar-laden products are a risk factor whereas better diet quality is a protective factor against depression. Better diet quality includes diets that are enriched in vegetables, fruits, legumes, grains and lean protein sources.
The Mediterranean diet is associated with a 30% reduction in depression risk as well as significant reductions in the risk of developing most chronic diseases. However, can a dietary change to one that is more in line with the Mediterranean diet improve mental health in individuals with mental health problems such as MDD?
Jacka et al. A randomized controlled trial of dietary improvement for adults with major depression (the ‘SMILES’ trial). BMC Medicine. 2017; 15(23)