Look around here:
http://www.wildfermentation.com/
...or here:
http://www.culturesforhealth.com/
Absolutely great sites... make your own full fat yogurt. Don’t feed the bad bacteria with any sugars. Yogurt has to be cultured for 24 hours to give the bacilli a chance to eat most of the sugars... commercial yogurts even unsweetened still have a lot of milk sugar. There are probiotic drinks in the refrigerated section of a health food store, including ones that are considered concentrates.. they are kombucha like, if you’re having sever distress and inbalance... I would take the concentrate and remove all sugars including simple carbs from your diet for at least four weeks. Switch to a paleo type diet, buy some raw fermented saurkraut... add to each meal. Do not heat the saurkraut! You can also make your own...but it takes at least 6 weeks to ferment.
>> Switch to a low net carb, low inflammatory, higher RS fiber diet: increase n3 fats, zero grains, zero added simple sugars, zero grain oils ... the new book “Wheat Belly Total Health” (Davis) seems to be the state of the art on how to eat (and is about vastly more than just the hazards of the novel grass seed sold to us as “wheat”).
> Can you give some examples of resistant starches, n3 fats, and higher-RS-fiber diet?
I’m posting this response here, as it’s getting a bit off-topic where the question was asked.
The blog post that really brought gut biome front and center in the paleo/primal/LCHF communities is this one on FTA*
http://freetheanimal.com/2013/12/resistant-primer-newbies.html
It has a list of RS foods, with much discussion in the comments.
* FTA contains a lot of material that is apt to offend FR readers, but the science is the science, and Richard (the blogger) goes where he thinks it leads.
For western humans, the gut biome situation is three separate problems, that must all be addressed at the same time:
1. get more favorable bugs working down there
2. eat foods that make it that far and feed them daily
3. stop killing them with gratuitous antibiotics, hostile foods (esp. wheat, sugars, maybe rice#) and pesticides (glyphosate, Bt GMOs, several popular artificial sweeteners) etc.
Davis (Wheat Belly) seems to have the best handle on the big picture, although only his latest book gives gut biome the prominence the topic requires.
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# Some rices, including California wild brown, contain disturbingly high levels of inorganic {natural} arsenic, for the US presently has no limit set.