This is only one small RCT but the results are intriguing. The gut biome was changed in a positive manner.

Bad microbes down and good microbes up. but only two weeks and 29 people. clinicaltrials.gov/ct2/show...

[Kuanyin]

Issues: According to the study it was paid for by the sponsor. This leads me to recall the great results we got when the pomegranate juice producers were also involved in sponsoring similar small-scale studies; “Healthy participants consume a capsule containing 5 g of mixed spices at culinary dose, mixed spice capsules contain 1 g cinnamon, 1.5 g oregano, 1.5 g ginger, 0.85g black pepper and 0.15g cayenne pepper for a total of 5.0 g.” I don't think the above constitutes “culinary doses”-- but much more. Zhao Ping-Li is a professor of nutrition at UCLA. I know her. I visited her offices many years ago when I was first diagnosed. The opinion I formed was that although she seemed patient-oriented (as opposed to just research to collect publish-or-perish-points), nevertheless, as in her previous studies, the the scale of this study is too small to really be meaningful. One could attack the microbiome problem from another direction by consuming prebiotics and/or some form of butyrate.

[Hidden in reply to Kuanyin]

Agreed. Small and short-term. I've run into the same issue with prebiotics. Funding sources, time, and size of studies. And I wonder how much good they would do someone if they consume 100 grams or so of fiber a day. Controls are unreal world also. Zero fiber compared to a prebiotic or probiotic?

[Kuanyin in reply to Hidden]

Good points! Personally, I stopped taking any probiotic last year because I was beginning to feel that taking them might create more mischief than they are worth. With regard to adding fiber to the mix (prebiotic and probiotic) further complicates matters. What I do now is eat a high fiber cereal in the morning to which I add a plant-based protein drink (usually pea protein) and a couple of varieties of fruit (currently pineapple and another summer fruit). So, by the end of the day, I usually wind up exceeding the daily recommended 25-30 grams of fiber. How do I know that this is "working"?, purely subjective--it includes the way I feel, bowel movements, etc. Unfortunately, too many variable to control for: there's no money, and little interest, for large meaningful studies. Most of us will need to work out the optimum combination for our own bodies. By the way, an excellent source of prebiotics and fiber is yams.