Our efforts to obtain prebiotic fibers/resistant starches to cultivate healthy bowel flora means recreating the eating behavior of primitive humans who dug in the dirt with sticks and bone fragments for underground roots and tubers, behaviors you can still observe in hunter-gatherer groups, such as the Hadza and Yanomamo. But, because this practice is inconvenient for us modern folk accustomed to sleek grocery stores, because many of us live in climates where the ground is frozen much of the year, and we lack the wisdom passed from generation to generation that helps identify which roots and tubers are safe to eat and which are not, we rely on modern equivalents of primitive sources. Thus, green, unripe bananas, raw potatoes and other such fiber sources in the Wheat Belly lifestyle.
There is therefore no need to purchase prebiotic fibers outside of your daily effort at including an unripe green banana, say, or inulin and fructooligosaccharides (FOS), or small servings of legumes as a means of cultivating healthy bowel flora.
HOWEVER, convenience can be a struggle. Traveling by plane, for example, makes lugging around green bananas or raw potatoes inconvenient. Inulin and FOS already come as powders or capsules and they are among the options for a convenient, portable prebiotic fiber strategy. But there are others that can be purchased. This is a more costly way to get your prebiotic fibers and you do not need to purchase these products in order to succeed in your bowel flora management program. These products are therefore listed strictly as a strategy for convenience.
Most perspectives on the quality of human bowel flora composition suggest that diversity is an important feature, i.e., the greater the number of species, the better the health of the host. There may therefore be advantage in varying your prebiotic routine, e.g., green banana on Monday, inulin on Tuesday, PGX on Wednesday, etc. Beyond providing convenience, these products may introduce an added level of diversity, as well.
Among the preparations available to us that can be used as prebiotic fibers:
PGX–While it is billed as a weight management and blood sugar-reducing product, the naturally occurring fiber–α-D-glucurono-α-D-manno-β-D-manno- β-D-gluco, α-L-gulurono-β-D mannurono, β-D-gluco-β- D-mannan–in PGX also exerts prebiotic effects (evidenced by increased fecal butyrate, the beneficial end-product of bacterial metabolism). PGX is available as capsules or granules. It also seems to exert prebiotic effects at lower doses than other prebiotic fibers. While I usually advise reaching 20 grams per day of fiber, PGX appears to exert substantial effects at a daily dose of half that. As with all prebiotic fibers, it is best to build up slowly over weeks, e.g., start at 1.5 grams twice per day. It is also best taken in two or three divided doses. (Avoid the PGX bars, as they are too carb-rich for those of us trying to achieve ideal metaobolic health.)
Prebiotin–A combination of inulin and FOS available as powders and in portable Stick Pacs (2 gram and 4 gram packs). Quite costly, given the generally low cost of purchasing chicory inulin and FOS separately. More on Prebiotin here.
Isomalto-oligosaccharides–This fiber is used in Quest bars and in Paleo Protein Bars. With Quest bars, choose the flavors without sucralose, since it has been associated with undesirable changes in bowel flora.
There you go. It means that there are fewer and fewer reasons to not purposefully cultivate healthy bowel flora and obtain all the wonderful health benefits of doing so, from reduced blood pressure, to reduced triglycerides, to deeper sleep.
Disclaimer: I am not compensated in any way by discussing these products.