There was an interesting blog post...One surprising thing is that maybe Pectin is better than RS-2!?!?
Abstract here:
http://www.ncbi.nlm.nih.gov/pubmed/23831725
I didn't read through the whole thing...Also they didn't test GOS but Pectin appears to be about 3x better than RS-2 in terms of affecting bifido populations.
So, again, that caloriesproper blog tends to just cherry pick whatever it can to promote its low carb narrative and largely ignores the hundreds of studies that show tremendous benefits from RS. The criticism is good, but it needs to be accurate, and the author of that blog seems to just be promoting his low carb narrative more than anything else.
In any case, I want to stress that there are a
lot of fermentable fibers that we should be eating. RS is not the only one and Dr. Grace/BG has shown evidence that RS by itself doesn't do as much as RS
in conjunction with fermentable fibers does. But, most of the fermentable fibers are pretty easy to obtain from diet alone, as long as you are eating healthy portions of plants. RS is just one that is almost completely absent from the modern diet and
that's why we are focussing on it. Why the caloriesproper author would try to diminish a powerful fermentable substrate — unless he was trying to promote his low carb narrative — is beyond me. You need
all of the fermentable substrates!
Secondly, the pectin study was done
in vitro, in colonic simulators. Not that it isn't useful information, but
in vivo would be more useful since the conditions are totally different.
Thirdly, while it's all well and good that pectin might increase bifido populations more than RS (nobody even knows if you even
want that much bifido), the problem with dumping RS for pectin is that pectin hasn't been shown to produce much butyrate
in vivo.
If you look at this table (and notice the large differences between
in vitro and
in vivo results
):
http://onlinelibrary.wiley.com/doi/10.1002/star.201000099/full#tbl2
As Tim Steele points out
regarding this table:
Tim Steele said:
Tim Steele // DECEMBER 01, 2013 9:25 AM You will see that pectin and gums are fermented almost completely into acetate, where RS is fermented into equal parts acetate, propionate, and butyrate. This is clearly where RS beats Pectin and gum, but I like the thought of including many different fermentable fibers in a good gut diet.
So, it's not to say that we shouldn't eat pectin. We should! But, getting pectin is pretty easy if you eat the right foods. And I think the evidence is overwhelming that RS needs to be part of the fermentation process if you want healthy production of the most beneficial SCFAs, like butyrate.
