Resistant starch

CONCLUSIONS AND FUTURE PROSPECTS

Animal studies have shown that different types of RS can differ substantially
in their effects on gut metabolism and host physiology (Le Leu et al., 2009).
Such variation can be assumed also to occur in humans. At the same time,
there is evidence that RS fermentation may vary markedly between individual
humans (Walker et al., 2011). Host factors, the nature of the dietary
substrate and the composition of the gut microbiota are all likely to play a
role in determining the fermentability of resistant starch in the large
intestine (Figure 14.4).
The likely inter-dependence of these various factors is explored briefly
below.
1. RS structure will determine its rate and site of fermentation in the large
intestine. The structure of dietary starch (particle structure, association
with other polymers, crystallinity, branching, retrogradation, cross-linking)
The likely inter-dependence of these various factors is explored briefly
below.



is known to determine its digestibility in the small intestine. It can be
assumed that these characteristics will also determine how rapidly resistant
starch is fermented in the colon, but less research has been done on this.
Rapid fermentation ofRSmay lead to complete fermentation in the proximal
colon, whereas slower rates will also support fermentation in more distal
regions, with the possibility of incomplete colonic fermentation overall.
2. Different types of RS may promote different groups of colonic bacteria. It
is possible that different forms of RS will prove to be accessible by
different groups of colonic microorganisms. This could result in selective
effects of starch intake upon the species composition of the colonic
microbiota, as well as differential effects on gut metabolism. For example,
it was suggested above that Bacteroides spp. may be best adapted to
utilizing soluble starch molecules. It has also been proposed that certain
types of RS might be more bifidogenic because of the high activity of this
group on high-amylose starches. If such selective effects occur, then
individuals who differ in the composition of their gut microbiota can
be expected to show different responses to RS intake as, indeed, is
suggested by the recent work of Martinez et al. (2010).
3. Host and dietary factors can influence what fraction of starch comprises
RS. Host factors (e.g. affecting secretion of digestive enzymes or transit
times) could play an important role in determining the undigested starch
fraction that arrives in the large intestine and its subsequent rate of
fermentation in the colon. This is also likely to be true for dietary factors
(e.g. the pattern of starch ingestion over time) and the presence of amylase
inhibitors of dietary origin (Wolin et al., 1999). Thus, it may be that the
types of starch that comprise RS will differ between individuals and also
within individuals over time, driven by changes in dietary intake.
4. Multiple factors (host genotype, diet, health, medication) have the potential
to alter the amylolytic community within the large intestine. It seems
possible that a few species of amylolytic anaerobe play key roles in the
initial degradation of RS in the colon, especially when the RS exists in
particulate form. If so, variation in these ‘keystone’ species between
individuals could result in individual differences in fermentability of
RS (Ze et al., 2012). One possibility is that certain species might be
eliminated by antibiotic treatment during an individual’s lifetime and may
fail to re-establish, as has been proposed, for example, to explain variations
in oxalate degradation between humans (Duncan et al., 2002).
We have to conclude that some of the most fundamental questions about
the factors that influence starch fermentation in the human colon, and its
consequences for human health, remain unanswered. A combination of
The Microbiology of Resistant Starch Fermentation in the Human Large Intestine 261
cultural microbiology, microbial genomics and molecular ecology promises
progress in understanding microbial fermentation of starch by colonic microorganisms.
This effort will clearly need to be allied, however, to an understanding
of starch chemistry, and to physiological and nutritional studies both
in humans and in animal models.

What to eat to put resistant starch in yourself?

Ideal Supplement Options
Raw unmodified Potato Starch such as (Bob’s Red Mill unmodified potato starch)
Plantain or “green banana” flour/starch such as (Barry Farm Plantain Flour)

After 6 months of daily 4 TBS of raw potato starch in addition to 20g of RS from foods and some dietary changes Tim had his gut micrbiome tested via The American Gut Project. The following are his results:



Tim Steele Resistant Starch tatertot American Gut Project

What is profound about these results is the reduced frequency of Proteobacteria. Proteobacteria are considered pathogenic and consist of species such as E. Coli, Salmonella, Vibrio and Helicabacter. Everyone has small amounts of these bacteria in their gut however the quantity and degree of proliferation is an important indicator of health.
Tim had the lowest amount of all comparable samples! In addition to this his most enriched microbes were all of the beneficial kind. The highest being Bifidobacteria notable for their health promoting properties.
Tim never did a test before taking the RS so we don’t know what his gut profile looked before the RS, however the improvements in health and well being speak for themselves. After many people have taken on the RS challenge they have seen similar improvement in well being as well.

scottyc33 wrote:I'm experimenting with adding some potato starch into my morning smoothie. Too early to tell if there's any benefit for me....

I think the most important point (also made in that video) is its probably wise to have a relatively healthy gut before adding in RS.

Or at the very least, taking some probiotics along with the RS is probably a good idea.