Sometimes it could be as simple as a needed nutrient that your body is lacking. The theory of an imbalance of serotonin in the brain may sound reasonable but it has never been proven. Yet many people, single mindedly, focus on this one possible cause.
B12 plays a central role in the regulation of your neurotransmitters like your dopamine and serotonin. The role that B12 plays with SAMe may have something to do with depression. SAMe is found in every cell in the body and is also involved in the breakdown and production of your brain chemicals that are involved in regulating mood. Not having enough B12 (or enough folate) can reduce your levels of SAMe.
B12 also plays a role in mitochondrial health. These power houses are responsible for each cells’ energy production which also plays a role in neurotransmitter signaling in the circuits that help to regulate mood. So no B12 means poor mitochondrial health.
Elevated cortisol levels which can be caused by chronic stress (from lifestyle, exercise and/or diet) can impact your moods as well. High cortisol levels (your fight or flight hormone) can cause oxidative damage to your mitochondria and in turn affect your neurotransmitter signaling. Nutrients including B12 along with folate, Omega 3’s , vitamin C, zinc and magnesium can protect your cells from this oxidative damage.