A protein rich diet, in contrary, decreases brain serotonin levels. (dujs.dartmouth.edu)
This results with a sudden drop of vitamin D3, leading to changes in the levels of brain serotonin. (fitnessandpower.com)
However, there has never been a published study that proves that people who suffer from depression or anxiety have issues with brain serotonin production or metabolism. (taliand.com)