I think it’s time for a follow-up on the Resistant Starch (RS) experiment embarked upon by my husband and me. We both started consuming Bob’s Red Mill Potato Starch on December 23rd, 2013. We are both considered “pre-diabetic” (although I’m definitely closer to crossing that line than he is). Many people in the Paleosphere (which is now beginning to look more like a “starchosphere”) who have tried RS have reported improvements in their fasting and post-prandial blood sugar, as well as improved digestion, lowered inflammation, and fun dreams. We wanted all these things too.
I’ll start with my husband’s experience.
He had no problems taking it. As far as side effects go, he experienced a little more gas and softer stools (though digestion/elimination wasn’t much of a problem to begin with, reportedly). He got in the habit of taking the potato starch with meals. Every meal he’d take a heaping tablespoon or so, for combined total of about 4T of RS a day. He continued to do this for 4 weeks. Here is a graph of his fasting blood sugar throughout this period of time:
If you drew a trend line through those data points you’d see a flat line. No change. Now, proponents of RS say you should give it 6 weeks. So he quit a bit early. Why would he quit? I’ll get to that in a minute.
But first, let’s talk about my experience with RS.
On 12/23/13 I started small because I didn’t know what to expect – a teaspoon a day, then two, and then I got bold and tried a tablespoon. BAD NEWS. I had massive bloating and abdominal pain for 24 hours…and was in the bathroom a lot during that time. Painful, burning, awful. Ok, but I was committed to this experiment! I went back to my previously well tolerated dose – 2 teaspoons a day (in 2 doses), and figured I’d work my way up more gradually. Did that for a week or so, and then tried 2 teaspoons at one time – again, BAD NEWS. So I started taking a fancy (read: expensive) probiotic along with 1 teaspoon of RS a day, hoping to cultivate some happy gut colonies that would “fix” whatever is wrong…because that’s what the potato starch people on the interwebs are recommending. Did that for a couple weeks. Then I stopped. Why did I stop? Same reason my husband did. And again…I’ll get to that in a minute.
Now, here’s the cool thing about having a blog. You have a written record of everything that’s going on…and even if things don’t make sense at the time, they often make sense in retrospect, and you can go back through your archives and try to put the pieces together. On 12/26/13, 3 days after I started taking potato starch as a supplement, I wrote this post. In it I wrote
I’ve shared myself honestly in this blog in the hopes of helping other people struggling to regain their health. I doubt I’m helping anyone, because I have no answers. I’m less healthy, heavier, more depressed, and less happy than I was 2 years ago when I started this blog.
That’s me – depressed. I remember writing it and I felt terrible. I had enough energy to mumble out a few lines on the blog, but I was a really dark cloud for a few days there.
I reviewed other posts I’d written around that time, and discovered that on 12/28/13 – 5 days after starting potato starch, I wrote this:
What I don’t understand is why the effects of estrogen have recently gotten so bad. I’ve never had breast soreness within the first week of my cycle before, I’ve never had headaches associated with hormone changes before, and usually my depression is pre-menstrual, not mid- or post-menstrual. Why is this happening now?
I now realize it was the potato starch. I didn’t put it together at the time – after all, why would potato starch cause me to feel like I was sideswiped by the estrogen train?
It wasn’t until I heard a podcast by Ray Peat, released a few days later on 1/1/14, that the pieces of the puzzle started coming together. When asked about the nutritional value of eating potatoes he said the following:
Adding butter or cream slows the digestion so it isn’t such a powerful insulin stimulant, but it also reduces the chance of what’s called persorption of starch granules. [...] A potato starch granule happens to be very big. Other starches are more the size of a red blood cell, but a potato starch granule is several times fatter than that. But even these huge granules bigger than cells can get squeezed right through the wall of the intestine, enter the lymphatics and the blood system, so within 30 minutes after you eat starch without fat, you see the starch grains circulating through your blood, and if they’re big they’ll plug up your arterioles. Studies in mice showed that a high raw starch diet accelerated their aging. You can demonstrate areas of every organ that were being killed by plugging up the arteries.
Hm…we’ll that didn’t sound good. Didn’t explain my recent symptoms, but it did clue me in that Peat didn’t think raw potato starch was a good idea. That spurred some more research. I came across this article at Ray Peat’s website. In it he states something similar to the quote above:
Volkheimer found that mice fed raw starch aged at an abnormally fast rate, and when he dissected the starch-fed mice, he found a multitude of starch-grain-blocked arterioles in every organ, each of which caused the death of the cells that depended on the blood supplied by that arteriole. It isn’t hard to see how this would affect the functions of organs such as the brain and heart, even without considering the immunological and other implications of the presence of foreign particles randomly distributed through the tissue.
Reading on in the same article:
The premenstrual estrogen-dominance usually leads progressively to higher prolactin and lower thyroid function. Estrogen is closely associated with endotoxinemia, and with histamine and nitric oxide formation, and with the whole range of inflammatory and “autoimmune” diseases. Anything that irritates the bowel, leading to increased endotoxin absorption, contributes to the same cluster of metabolic consequences.
Aha! Anything that irritates the bowel (resistant starch), leads to endotoxin absorption (headaches, feeling like crap) and estrogen-dominance including higher prolactin (sore breasts) and lower thyroid function (depressed mood, lack of energy). Well, that makes sense. Obviously, not everyone reacts to RS this way. My husband didn’t. Dozens (hundreds?) of people commenting over at Free the Animal aren’t having problems (although a few are). But for me this stuff felt bad in doses over 1 teaspoon. That’s not why I stopped taking it though. My husband and I stopped taking it because of the persorption issue. Peat seems to think this is a significant reason to avoid starches, unless they’re well-cooked and served up with fat – essentially making them more digestible and definitely not “resistant”.
I can’t say Peat is completely alone in his assertion that RS has the potential to be dangerous…but he’s almost alone. A Google search indicates very few people talking about the issue of persorption; most of the ones doing so are bloggers who follow Peat like Rob Turner and Andrew Kim. Now, it’s no secret I love me some Ray Peat, and the folks who follow his recommendations I’ve found to be invariably very intelligent and science-oriented. But I trust no one….so I do my own research. I did a search of pubmed for “persorption” – there’s not too much there, and a search for “persorption + starch” yielded even less, but a few studies stood out as relevant, including:
1. Persorption of raw starch: a cause of senile dementia? by BJ Freedman. The full article is not available, and the abstract suggests this is a review, rather than an experiment. So it’s someone’s opinion about research that has been published. It seems the conclusion is that exposure to raw starch could result in the loss of many neurons, and long term this could mean dementia. Honestly, I don’t typically put a lot of stock in theory pieces like this. I’m sure he raises good points, but I want empirical science.
2. Oral cornstarch therapy: is persorption harmless? by Gitzelmann and Spycher. Another review. “The possibility of late adverse reactions to persorbed starch should not be disregarded.”
Pretty much all the rest of the articles involved studies by G. Volkheimer, the scientist Peat refers to when he discusses the importance of starches being well cooked. Here, Peat cites this article by Volkheimer: [Persorption of microparticles] (Original article in German). The abstract states:
Since persorbed microparticles can embolise small vessels, this touches on microangiological problems, especially in the region of the CNS. The long-term deposit of embolising microparticles which consist of potential allergens or contaminants, or which are carriers of contaminants, is of immunological and environmental-technical importance.
Another of Volkheimer’s articles is available full text for free, and details his experiments: Passage of particles through the wall of the gastrointestinal tract. He describes how they dyed the potato starch (and other substances with relatively large particle size) with Lugol’s solution so they could watch where the particles moved around the body. Apparently they moved all over the place including cerebral spinal fluid, the milk of lactating women, and the placenta of pregnant women. Toward the very end of the article, it says,
Enzymatic degradation of starch granules in the body fluids was demonstrated.
Well that sounds good, right? The starch granules are degraded by enzymes. And the graphs do show that in the case of each of the substances tested the quantity of particles found in the blood diminished over a fairly short period of time. So no worries then?
It goes on to say:
Deposition of embolized starch granules and other persorbed particles in the lumen of the smallest vessels was observed in animals after long-term oral administration. in pigs, dogs, chickens, and rats fed with particles, we found individual particles as microemboli in the lumen of the smallest vessels a long time later.
I had to look up “embolized.” It means blocking a blood vessel. So apparently they found that these large persorbed particles blocked small blood vessels, and did so for a “long time.” If I took the time to read all of Volkheimer’s work maybe I’d know what he means by a “long time.”
In any case, I don’t know what long-term use of RS would do to my itty bitty blood vessels, or to the organs they’re attached to and I don’t really want to find out. That’s why I stopped the potato starch, and recommended to my hubby that he stop too. And he did.
I asked Richard Nikoley for his take on all this. He and Tim “Tatertot” Steele have been spearheading the RS movement, and are in the process of writing a book together on the subject. They responded to my inquiry quickly, and after researching my questions for a bit suggested that current research indicates that persorption is very common, occurring with particles much smaller than potato starch, and may have some beneficial effects:
It is possible that these particles have beneficial health effects not only in the intestinal lumen but directly in the blood stream and on the endothelial surface of vessels.
Hm…Ok, that could be. But this article doesn’t refute Volkheimer’s research that says the large starch particles clog up little blood vessels. In any case, Richard suggested I research this and write it up on my blog. So here it is.
Ray Peat has been right about many things for me, and I’m just getting started with him. I have no reason at this point not to trust him. So, I’m choosing to trust him and his interpretation of Volkheimer’s research, and I’m avoiding the raw potato starch. In spite of this, I truly hope the conclusions drawn as a result of this research are wrong, and that RS is actually as healing as the many current anecdotes suggest it is. But just in case, here’s a thought: Maybe RS combined with probiotics is a way to get your gut in good working order, after which its use should be discontinued, in order to avoid potential problems associated with long-term use. It may be wise to think of it as an intervention, rather than as a way of life.
Something to think about.