This infographic has some good information regarding the relationship between nutrition, the gut and mental health. I do not completely endorse all of the information in it, however.
Many people have sensitivity to foods that are considered healthy for the general population; if you have an allergy or food sensitivity you MUST avoid eating it or you are likely going to have some type of reaction – it could be either physical such as bloating and abdominal pain, eczema or acne, asthma, muscle pain, or other symptoms OR it could be emotional and behavioral reactions such as depression, anxiety, hyperactivity , fatigue, brain fog. Also, grains that contain gluten are difficult for the majority of people to safely eat – gluten causes intestinal permeability and leaky gut in almost everyone and so is best not eaten. There are other foods that cross-react with gluten, such as other grains, dairy, and coffee. Both gluten and casein (found in dairy products) can be converted into morphine-like substances in the body and both cause direct negative effects as well as an addiction to that food. The most common food sensitivities/allergies include: dairy, gluten, sugar, eggs, corn, peanuts and tree nuts, shellfish, and soy. Many people have sensitivities to oxalates, salicylates, phenols, and histamines – making foods that are otherwise considered healthy to be a problem for them.