Fermented Foods: Definitions and Characteristics, Impact on Gut Microbiota etc.

"Feeling better" could be real or it could just be cognitive bias. Did you use an app to record your mood multiple times a day? Were you taking less time (better contration) on cognitive tasks? Measurably fewer aches and pains? Better performance during workouts? Or did you have blood panels done and some values were better? Or none of those things?

That you say it's delicious is a confounding factor, as well, because eating food that tastes better improves your mood which can make you feel better without any nutritional or microbiome-related health effects.

To be clear, I'm not criticizing fermentation at all, just whether this anecdote provides any meaningful evidence for anything.

Also, even if there is some statistical significance since "a couple" apparently means far more than 2, since fermented foods displaced other things, what did they displace? Could those have been making you unhealthy rather than fermented foods making you healthier? You'd have to trial non-fermented dairy and tea and veggies as a control, and that control doesn't work very well with dairy because non-fermented dairy is high in simple sugar which can be bad all by itself.

I don't have any feelings on possible health benefits either way, but I like some fermented foods and was curious if there was something to learn. Oh well.

As someone who frequently conducts literature searches, I find these review papers critical to my work. If taken at face value, a it lets me know that I need not look further. If not, it is a starting point for cross-references.

That said, I would have liked to see a methods section with a list of search terms.

What I read is that the _majority_ of the studies are not good quality. There are very few high-quality studies e.g. double-blind randomised controlled trials and crossover studies, etc and most studies have a very small number of subjects. However, it's hard to fault a double-blind RCT for low quality because it has few subjects. Low statistical power, OK, but if the methodology is sound then the paper has merit.

Given that these studies go back a number of years and there is still no conclusive evidence for any health benefits from the consumption of fermented foods it is useful to have a summary of the current state of research.

We know small changes in diet can have a large effect on the microbiome. For example, adding seaweed to a mouse diet can select for microbes with the ability to digest particular polysaccharides within seaweed (https://www.nature.com/articles/s41586-018-0092-4). A company spun out of the Sonnenburg lab at Stanford is using this tech for microbiome therapeutics in humans (Novome). Those mice were given 10% seaweed by weight, so that serving of sourdough is right in the same range.

My point is, the researchers designing these experiments know what they're doing, and they're well thought out. You can't criticize something if you don't know the details of the field.

You can get it at Mitsuwa in the Bay Area. 99 Ranch might carry it as well.

Not sure about elsewhere.