I suspect that many here consume milk Kefir made from milk grains for it's probiotic content, and the health benefits it imparts. I know I do, and have been doing so for over four years. Significant recent research suggests that consuming prebiotics at the same time as your probiotics enhances their passage through to the colon. In the colon they help to sustain your gut biome.
The prebiotics of particular interest are the non-digestable soluble fibres that are fermented by the bacteria in the biome to produce the short chain fatty acids - butyrate, propionate and acetate.
I make my kefir from the best milk I can get - full cream A2, drinking 400 ml of it well fermented daily. To which I add 15gms of raw potato starch and 15gms of Inulin. Combining probiotics and prebiotics is known as synbiotics, giving the benefits from their synergism.
At 75 and on NO prescription medications I seem to be doing pretty well.
Alison
PS I work out on a treadmill daily. Just 30 mins of brisk walking.