I’m a big believer in fish oil. In my late 30s I experienced a consistent feeling of unwell ness and what I describe as “brain fog” so badly and consistently I went to the dr about it. Turned I had high blood pressure and high cholesterol. Dr wanted me to modify my diet and if it didn’t improve he wanted to put me on statins(!)

Fish has never been part of my diet. Started using fish oil, eating Cheerios, vitamins and some excercise. Started makeung a point to include seafood 2 times a week. Long story short, 6 months later all my numbers were in line.

The most striking thing I recalled from this was the fish oil, brain fog went away, I felt a great deal more mental acuity.

Fast forward to today; that was all 8 years ago, in the interim I stopped all that and the brain fog and unwell ness are back. I started fish oil again, and the effect was immediate. I even remarked to my wife how much better I felt.

That’s all anecdotal, and probably placebo effect anyway, ymmv.