As far as mood & temperament, there’s a strong connection between the gut and brain. So when your gut is messed up, your moods can definitely be affected. I just read another article about it the other day that you might be interested in:
“Psychologists used to believe that our feelings were the result of chemical reactions in our brain. Fast forward to today and what we know is that our gut plays a profound impact on our mood.” The article goes on to talk about how good bacteria improves mood but bad bacteria contributes to anxiety and depression. It talks about specific strains of probiotics that can improve mood.