For someone who has been forced to try countless substances / diet regimens / health strategies due to a pervasive chronic disease, I beg to differ. There's so many things that you can personally do that will alter your cognitive abilities, sometimes to an incredible extent. The tricky bit is that there is indeed no silver bullet, and what works for someone might do nothing or create harm for another. So in my opinion, understanding that there are alternatives to resignation is really the critical component.