Metabolic syndrome, and hypothyroidism (both diseases of decreased cellular energy production) are correlated with reduced intelligence.
Hypothyroidism obviously has a lot more consequences than just decreased cellular energy production and as to the metabolic syndrome, I’m not sure I’d call it a “disease of decreased cellular energy production” at all, it looks much more like a breakdown of some regulatory systems to me.
Of course, there are many ways to harm brain (=reduce intelligence) which do not involve limiting ATP in the cells.
Hypothyroidism obviously has a lot more consequences than just decreased cellular energy production and as to the metabolic syndrome, I’m not sure I’d call it a “disease of decreased cellular energy production” at all, it looks much more like a breakdown of some regulatory systems to me.
Of course, there are many ways to harm brain (=reduce intelligence) which do not involve limiting ATP in the cells.