I never get tired of seeing well-designed studies on my favorite thing in the world: fiber!
Well, here’s a couple research articles describing Bob’s Red Mill Potato Starch, man-made RS4, and an inulin supplement. tl/dr: Fiber good!
Study 1 – 4TBS Bob’s Red Mill Potato Starch for 10 days, 20 people
Butyrate increased by 67% average. Bifidobacteria and some known RS degraders increased significantly.
How’s that for vindication? Exactly as we have been saying around here for years. The only flaw in this study was that it only measured changes after 10 days of supplementing. I wish they had extended it to 6-12 weeks at least and used some different doses, and comparison fibers. But still, great paper giving much credibility to using BRM Potato Starch as a dietary fiber supplement.
Study 2 – RS4 (from wheat), 12 weeks, 86 people
Tested on people with Metabolic Syndrome:
- Cholesterol, blood sugar, waist measurement, weight all went down significantly
- Populations of beneficial bacteria increased
“In conclusion, this study provides evidence that dietary RS4
supplementation selectively changes the gut microbial and metabolite
environment as well as associated host metabolic functions.”
I do not believe there are any consumer-type RS4 sources available to purchase, this seems to be a product made and used by the food industry to add functional effects in processed/snack foods. When you start to see “High in Resistant Starch” on Ho-Hos and Ding-Dongs…sorry, still not healthy. I really don’t think there is a natural source of RS4, it’s made by ‘cross-linking’ starch chains using chemical modification. There are not even many good descriptions of the process, which seems to be tightly guarded. Until we are satisfied that RS4 is a good fiber, remember there is always potato starch, inulin, and a whole host of other fibers out there, including those in real foods!
Study 3 – Inulin prevents hunger cravings
Here we have some smart scientists who made a concentrated inulin extract which is shown to “turn off” cravings for certain high-reward foods.
Eating a type of powdered food supplement, based on a molecule produced by bacteria in the gut, reduces cravings for high-calorie foods such as chocolate, cake and pizza, a new study suggests.
These guys used something called “inulin-propionate ester” to invoke a release of the SCFA propionate in the gut. This is the same thing produced when we eat regular inulin (or RS, or other fibers).
Interestingly, this paper also confirms what I have been saying for years…you need lots of fiber to reap the rewards! In this case, they estimated it would take 60g of fiber to reproduce the same results as using a small amount of inulin-propionate ester. I’ve long been an advocate for 20-50g of fiber daily…do we need to raise the bar?
“The amount of inulin-propionate ester used in this study was 10g —
which previous studies show increases propionate production by 2.5
times. To get the same increase from fibre alone, we would need to eat
around 60g a day. At the moment, the UK average is 15g.”
Fiber is good for us, and knowing the different types is extremely important. Most of what is listed as “fiber” on food labels is non-fermentable fillers. To get a meaningful amount, we need to be ingesting the fibers that are known to be changed into short-chain fatty acids in the large intestine. These are fibers known as resistant starch, inulin, FOS, pectin, glucomannan, oligosaccharides, and others. It’s important to get as much fiber as possible from real foods, like onions, garlic, leeks, beans, potatoes, and all manner of whole grains, fruits, and vegetables. However, if you need a supplement, try inulin, potato starch, or one of the many supplements available. If you buy a commercially prepared fiber supplement, get one that has no artificial colors or flavors and consists of just fermentable fiber.