In my opinion there are 2 different things at stake here.
Brain fog : leaky gut
Absentmindedness: heavy metal toxicity
Elio, you had mercury in your hair analysis, right?
Anyhow, I treat brain fog with enemas, carrot juice, salt and garlic flush.
I treat Absent Mindedness with lecithin and good oil (flax seed, olive).
Heavy metals attack your nervous system. And these are nutrients that prevent the nerve cells' (brain & nervous system) oxidation.
Furthermore, I've found a site, ages ago (I forgot where) and it said that these nutrients are good for these respective metals:
Nutrients Known to be Protective Against Heavy Metal Toxicity: