digestibility of amylose vs. amylopectin ( Re: Invasive Breast Cancer)

[Guest guest]

> here's a study that found amylose to be significantly more resistant to

> digestion than amylopectin:

>

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve & db=PubMed & list_ui

> ds=8935440 & dopt=Abstract

>>>Suze,

I couldn't figure out how it was saying that amylopectin was more easily

digested. It said that amylose corn contained more " resistant starch " but

that

wasn't in the results part of the study, that was in the intro. It went on

to

give figures in terms of energy per gram of resistant starch, without

specifying anything about either of the two diets.

Assuming " resistant starch " is starch that can't be broken down, than they

are implying the amylopectin is better digested, but they didn't write any

*findings* about that in their study.

---->perhaps i'm misunderstanding the results then. it says:

RESULTS: Total fiber uncorrected for resistant starch was 35.2 g and 48.8 g

in the AP and AM diets, respectively. The AM diet contained an average of

29.7 g resistant starch (16% of total starch) while the AP diet averaged 0.8

g (less than 0.01%).

----->i understand that to mean that the amylose diet had 16% starch that

resisted digestion, while the amylopectin diet had less than 0.01% starch

that resisted digestion. meaning the latter is significantly more

digestible, in contrast to what gotschall is claiming. Do you have a

different understanding of it?

>>>Starches are very sticky. It seems feasible that Amylopectins might

aggregate despite their shape. I have no idea. Neither starches are

allowed on SCD

though.

---->that may be, but i'd like to know if gotschall is mistaken about the

digestibility of these starches, because people are reading that in her book

and on the web and believing it.

here is an excerpt from another article that refutes it:

" The ratio of amylose (straight chain of 50 to 300 glucose molecules) to

amylopectin (larger, highly branched chain of 300 to 5,000 glucose

molecules) in food is also an important factor that influences GI values.

Foods with a higher ratio of amylose to amylopectin such as legumes and

parboiled rice tend to have lower GI values. This is because the tight

compact structure of amylose renders it physically less accessible to enzyme

attack and therefore harder to digest, and amylopectin molecules, on the

other hand, are larger and more open to digestive enzymatic attack. "

http://www.lipid.org/clinical/articles/1000004.php

and:

" Variation in amylose/amylopectin determines how easily the starch is

digested by humans and domestic animals.

High amylose cereal starch is poorly digested or has a slow rate of

digestion. It is a compact molecule and enzyme access is restricted compared

to the more open branched amylopectin. "

http://www.library.uq.edu.au/bio/lectures/agrc2001_2003/carbo.doc

the above explanations are my understanding of the difference between the

two. in fact, this also indicates (and i read elsewhere) that amylose starch

is fodder for colonic bacteria, albeit the beneficial kind that produce

SCFAs from it. if amylose has a lower GI index, that's also pretty

indicative that it's less digestible than amylopectin. yet gotschall has

spent a number of years researching the effects of starch on the digestive

tract...? so either she's wrong about something that she should know very

well, or these other sources are wrong, and the GI indexes are wrong.

Suze Fisher

Lapdog Design, Inc.

Web Design & Development

http://members.bellatlantic.net/~vze3shjg/

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