Hi Helen, You mentioned "I also doubt probiotics food can bring enough probiotics to human body. I always feel supplement is higher dose."
Ahh, the power of advertising and the media! We have been taught to believe that. Humans existed for millenia without supplements, and even now some of the longest-living people on the planet are in primitive societies that eat a natural diet - I doubt any of them has ever heard of a supplement.
"Higher" is not always better - many supplements, if taken in too high a dose simply come out in urine or feces. or are not well absorbed by the body and are similarly excreted. Or the active ingredient(s) are killed by the gastric juices in the stomach.

Remember, the promoter and manufacturer are not required to demonstrate how your body uses these - only what is in them when you swallow them, and even then, independent proof is not required.

Unfortunately, other supplements like B vitamins can deposit in our organs or body fat and cause serious health issues.

Finally, supplements can interfere with medications we are using - and just because they are "natural" does not mean they are more beneficial that the drugs.