A recent study, found that dietary folate impacts wether or not you worry, which is a future-oriented type of negative thinking. Interestingly, rumination, which is past-oriented negative thinking is not altered by dietary folate intake. Both are directly associated with depression and anxiety!
I always recommend testing to know what your nutrient deficiencies are and then treat the condition accordingly. That provides a more precise and beneficial response to any recommendations on what supplements to take for mental health. I see remarkable changes in patients using this approach, especially when paired with peptide and hormone balance therapy, for helping to be free of anxiety and depression.