If you’re healthy, no major complaints, then you probably won’t benefit from tweaking your ‘biome. Ymmv. But if you’re gonna do it anyway, here are some tips (mostly my opinions).
1) Listen to podcasts by some of the experts like Bryan Davis (Doc Fermento) and Grace Liu (Gut Goddess). Jane Plain (ItsTheWooo) also has some unique views on the topic. If there are more good ones out there, please leave them in the comments!
2) Start with small servings of fermented foods: sauerkraut, kimchi, kefir, pickles, etc. Same goes for prebiotics (like 1/4 TEASPOON, not TABLESPOONS). Too much can easily cause bloating, GI discomfort, gas, diarrhea: no bueno.
4) My personal bias when it comes to supps: it’s better to supplement a few strains combined with selective prebiotics than to use products with a ton of strains. For example, I prefer Jarrow Bifidus over SBO bombs because the former has just a few strains we know are beneficial, whereas the latter has a lot of mystery strains. And combine with galactooligosaccharides, garlic, leek, onion, etc., to selectively feed ’em.
5) Many Paleo-biome studies show ‘variety’ is a potentially valuable ancestral characteristic, but I’m wary supplementing a million random strains to achieve said variety… seems like a high possibility of something going wrong. The ‘biome has been implicated in regulating brain functions, mood, immunity, stress, adiposity, etc., etc. Do you really want to hit it with a million mystery strains? And I imagine if something does go wrong, it could be very difficult to fix.
6) Anecdotally, people complain that the effects of certain ‘biotics on gut function crap-out after a few days. Try a different product, and see points 3 and 4 (above). Also, I totally wouldn’t be surprised if regulating gut function turns out to be a relatively minor role of the ‘biome (see point 5).
To summarize, I have no strong opinion about total microbe numbers or variety. I do believe higher percentages of certain strains are healthy and the evidence supporting this is pretty strong. For example, many healthy populations have high bifidobacteria, many sick populations have low bifido, few sick pops have high bifido, etc. This is where my collective thinking on the topic arises. There are other potentially healthy strains, but few with such wide-ranging support. Maybe.