Beta-glucan is a special soluble fiber (NSP)-- it's not made by mammals.
It's found in yeast cell walls, whole grains, and mushrooms. It's been
shown to not only affect the microbiota but also improve immune
function, wound healing, metabolic dysregulation, cancer/tumour sizes,
and inflammation.
A recent study tracked the fate of beta-glucan in the
gut and immune lymphoid tissues. Researchers
found "these large -1,3-glucans were taken up by gastrointestinal
macrophages and shuttled to reticuloendothelial tissues and bone marrow.
Within the marrow, the macrophages degraded the -1,3-glucan and
secreted small soluble biologically active fragments that bound to CR3
of mature bone marrow granulocytes. Once recruited from the bone marrow
by an inflammatory stimulus, these granulocytes with -1,3-glucan-primed
CR3 could kill iC3b-coated tumor cells."
Resistant starch (RS) is found to be quite as plentiful as beta-glucan
and plant fibers however cooking breaks it down to a form that we can
digest (enzymatic, mastication, acidic). The amount remaining in a food
that escapes our digestive juices varies by many factors -- species,
maturity of the plant, cooking/cooling methods, food acidity, to name
just a few. RS is different from beta-glucan and fiber due to its
tightly bound double helical glucose polymer structure. Yes it is coiled up like DNA....
Solubilization in cooking water 'releases' the starches into a gelatin
matrix which our spit amylases and pancreatic carb-ases can breakdown
to glucose for absorption in the stomach and small intestine. Any
undigested amounts enter the caecum and colon. The amount of SFCA
produced upon caecal and colon fermentation varies as well depending on
an individuals microbiota species, large intestine health status, etc.
