candida die off can cause Depression & anxiety... go slowly with the diet. I dont know about the diet but be sure that it includes all B Vitamins, Magnesium, Zinc, Tryptophan & Tyrosine and Omega3 all are REALLY necessary to prevent/treat depression.
Also be aware of blood Sugar imbalances as it can cause depression. Chromium is very good to help balance blood sugar.
Quit any stimulants, alcohol,stress.... Vitaminc C is recommended if you are under stress.