with proper diet most diseases vanish

[reeay]

I see on this forum, posts about healthy brain foods, etc. Unless we're talking about preventing specific neurological illnesses, any sort of healthy foods that keep your entire being healthy may help to boost brain functioning. There are foods and substances that temporarily effect your brain functioning, but it will not change your brain functioning on a permanent basis.

If someone is talking about preventing dementia or alzheimer's then there are foods and healthy lifestyle approaches that have shown to prevent or delay illness symptoms.

Malnutrition may affect your intellectual functioning (and pretty dramatically), and long-term malnutrition will effect intellectual and emotional functioning... so if malnutrition is the basis for mental illness-like symptoms, then proper diet will ameliorate problematic symptoms. But if someone is emotionally impoverished (e.g., lifetime of difficult relationships that leads to mental illnesses), then food may help but will not help symptoms of mental illnesses to 'vanish'.