Here's what ended my brain fog:

Vitamin B complex, 1/2 a 50 mg pill a day
Copper supplement, 1 mg every 2-3 days
Whey protein (for amino acids) 1 scoop every 2-3 days
Flax seed meal 1 tbspn every 2 days
Eating more red meat was crucial, also eating some calf's liver every few days. This may be disagreeable, but I think the iron and copper in the red meat and liver helped.

I no longer have any brain fog whatsoever.