Gut microbiome and intelligence

I absolutely think so, and I've experienced it myself to drastic degrees. I thought I mentioned in my FMT reports that I was experiencing changes as drastic as the character in the novel "Flowers for Algernon", but I don't see it mentioned there. I found it in my personal journal:

April 10, 2017
Read the book "Flowers for Algernon" around this time.
Mentally retarded kid made highly intelligent via experimental procedure. Book covers his development and the affect it has on others in his life. He regresses back to the retardation at the end.
His experience of regression resonated strongly with me since I experience it constantly.
@Michael Harrop

Very interesting. Did you experience a perceived increase or a decrease in intelligence?

It might be interesting if someone actually did an FMT from a genius to see what it can do.
Did you experience a perceived increase or a decrease in intelligence?
Both. Lots of ups and downs.

It might be interesting if someone actually did an FMT from a genius to see what it can do.
I have plenty of genius-IQ applicants to I haven't ranked them highly due to other factors such as stool type. People are welcome to use them though.
I can most certainly confirm one thing for certain with respect to myself and creativity and gut health. About 10 years ago when I changed my diet drastically, there were monumental hurdles in my percussion and drumming abilities that were overcome. I used to play the same boring monotonous practice routines for years. Over and over I would sit down with no real drive or interesting revelations to my abilities or creative process. The same cover songs were attempted over and over and of course I still semi enjoyed playing them. Then, over the course of a few months along with the vitamins and minerals I was starting to take as well as landing a job outdoors in the blistering FL heat, I noticed that jittery anxious drumming style was starting to go away. Almost like the brain fog and stress of keeping up with the groove was almost completely gone. I could breathe and think inside and outside of these fast and slow changes. It dawned on me one day when I nailed an old Steve Gadd part that had alluded me for years. The complexity was always a god level tier that no matter how I executed, there was no amount of listening or practice that could finish it with out fumbling. I took my 21speed bike out for a decent 17+mi ride listening to some old classics in my ears and lo and behold it was apparent I could finally hear it. Truly hear it and know it. I sat down at my drum kit about an hour later and just like a kid learning something for the first time, it happened. I was calmer, more focused, open to chaos but still able to control the playability with out it overwhelming me. Honestly, just being a more healthy person. Eating less processed foods out of a box and cutting out all the soda, junk food and sweets. Adding more vitamins and minerals, probiotics and drinking more water has had a huge mental and physical benefit. Surely this added to my creative process's and the technical execution in my abilities. If I had to describe it, it was like taking all the static out of the process and having a closer direct line to the expression of what ever your feeling at the time. I am no where near the dull and almost caveman like percussionist I used to be prior to taking back my diet and nutrition. Im pretty sure there was a process of detoxification that I started from the inside out and most certainly over time it helped me play and express my self better.
While searching the internet I came across one study.

The study claims a link between gut bacteria and cognitive performance.

Now, does it mean that by changing our gut microbiome we could potentially raise our IQ?
That's interesting. I can tell you I have a friend with an IQ above 140. She received a Harvard scholarship and was valedictorian of her class. She was in the process of getting her PHD, when she had a series of reoccurring sinus infections and took antibiotics to treat it for over a year. She told me her gut health deteriorated, she was diagnosed with celiac disease and ADHD. I also noticed she was having trouble concentrating and word finding. This is a woman who has graded English papers a year prior. I noticed the deterioration in her intelligence when she spoke. So, I do believe having a healthy gut can influence intelligence.
I feel like having a happy gut with all the bells and whistles functioning ideally is a recipe for balance and negates internal stress, which does have manifestations either mentally or emotionally. Dr Gundry has an entire encyclopedia referring to gut bacteria causing brain signals that warrant junk food cravings, sugar ect. Also, having a diet that takes care of the gut flora achieves better mineral absorptions and toxicity imbalances thus the potential for more adequate brain health and cognition. As far as your friend is concerned... I feel like lack of sleep and stress might be more of a condition for such a go getter on the academic front. I have no experience with antibiotics in my life. I was only ever bed ridden ill one time in my life when I was 15. We have a reclaimed water/dual water system here in Florida which is not potable water and shall only be used for car washing and lawn irrigation. I did not know that, after the system was introduced. One hot summer of bike riding and playing basketball, I drank from a hose of this reclaimed water. The next day i suffered a fever, followed by a full bowel release and vomiting. My parents always just reminded me to sweat it out in bed and use ice and cold showers to relax the fever which I did. My family didn't have health insurance or primary care and both parents worked overtime. It took 6 days but I didn't get any medicine or antibiotics. I constantly checked my temperatures and after the first 2 days it was never above 101. My Mother made me drink Clubsoda's and Ginger ale and eat plain white bread, the best I could. I felt much better after drinking some salt water and rinsing out my sinuses. Then was able to drink some OJ mixed with water. I lost about 8lbs and had a fever for the 1st 3 days... That was the last time I was grossly sick. My mom told me when I was very young I had an ear infection that required a shot and did get a Tetanus shot when I was 10 when a rusty lawnmower blade punctured the top of my hand requiring stitches. I rarely get headaches and was always told that dehydration was the cause and would gorge water to the avail of not taking aspirin as well. Apparently a good gut is representative of your immune system. I am a recipient matched doner at a bioplasma center and have my antibody titers tested regularly. I was told my baseline is an above average antibody titer with respect to the the other doners. I swear the apples, raw foods, fibers as well as the gorge of 90vitamins and minerals as well as full spectrum proteins I blend every morning are all the difference.