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Carbs, amylum, polysaccharides, call it what you will, starch in all its forms has gotten a bad rap lately. Some of this negative attention is valid, as excessive starch in the diet can contribute to many health problems, not to mention gut issues.
The truth is that not all starch is bad, however, and one starch in particular called resistant starch (RS) has been gaining a lot of attention as it has been shown via research to be extremely beneficial to overall health.
Ironically, it is especially helpful for those with gut-related problems. This may seem hard to believe at first given that many forms of starch are avoided on gut healing diets like GAPS.
Resistant starch is a type of starch that does not break down. It literally “resists” digestion, instead of being absorbed as glucose like most starches. Instead, resistant starch travels through the small intestine to the colon where it is turned into beneficial, energy-boosting, inflammation squashing short-chain fatty acids by intestinal bacteria.
But, be wary as all forms of resistant starch are not the same!
Four Types of Resistant Starch
RS Type 1 – Starch that is bound by fibrous cell walls and therefore resists digestion, such as beans, legumes and grains, and nuts/seeds.
RS Type 2 – Indigestible due to its high amylase content when in its raw forms, such as found in potatoes, green bananas, tiger nuts, and plantains. Heating or over-ripening these foods renders the starch to be no longer indigestible though some reforms when cooled.
RS Type 3 – This type of resistant starch is the result of a process called retrogradation- when starches are cooked and then immediately cooled, which allows the digestible starch in some foods like rice, potatoes, and beans to be more resistant to digestion.
RS Type 4 – Industrial resistant starch that does not occur in nature. It is man-made via a chemical process and should be avoided.
Traditionally, it was believed that starch was fully digested and absorbed in the small intestine, but we now know this is not true.
At least 10% of the total starch in a typical Western diet is resistant starch, which acts very much like fermentable fiber. In general, starchy foods that contain RS Type 1 and RS Type 2 will yield greater amounts of resistant starch than any other foods, especially compared to fully cooked starches. Therefore, how a specific food is prepared can determine how much resistant starch it will contain.
Benefits
The research has shown that in general, moderate levels of resistant starch intake is well tolerated by healthy people, and also provides many benefits to improve some of the most common health issues many people face today, such as:
- Stabilizing blood glucose levels and increasing insulin sensitivity
- Improving cholesterol and triglyceride levels
- Reducing appetite and increasing satiation, which can lead to weight loss and easier weight maintenance
Although resistant starch has many benefits to the entire body, it most notably has been studied for its positive effects on gut health.
RS and the Gut
Our gut harbors hundreds of different species that we are still learning about, but in the last few decades, we have discovered that specific bacteria and especially the quantity of them can make a huge impact on our overall health and wellbeing. For example, bacteria in the small intestine outnumber the body’s cells 10 to 1, so taking this into consideration, that makes us only 10% human!
The main reason why resistant starch is so beneficial is that it feeds the friendly bacteria in your colon, turns them into important short-chain fatty acids, such as butyrate (known to help reduce inflammation) and is extremely helpful in cases of autoimmunity, IBS, colitis, and allergies
Resistant starch acts and is the preferred energy source for cells lining the colon. Researchers from the RIKEN Center for Integrative Medical Sciences found “that the guts of mice with colitis increased in regulatory T cells, and their inflammatory symptoms improved after they were given butyrate in their diets.”
Other gut supportive benefits of resistant starch include:
- Maintenance of normal gut function – motility, recycling of waste products, bile acids, water and increase electrolyte absorption
- Increase good bacteria (flora) which protects against the growth of bad bacteria and pathogens
- Vitamin production of biotin, folate, and vitamin K – which can only be produced through bacteria
- Increase immunity – Roughly 80% of immunity is located in the gut
- Enhancing breakdown and elimination of toxins
A Word of Caution
If you’re not used to consuming resistant starch or have digestive problems, I suggest adding it in slowly to your diet as it can cause gas and discomfort while the body becomes used to it!
There is also some concern around resistant starch exacerbating digestive issues for some. If you’re working on healing from any digestive or GI illness or infection/ bacterial overgrowth, such as SIBO (small intestinal bacterial overgrowth) or IBS, I don’t recommend introducing resistant starch until one is in at least the partial remission stage as it may add to the fermentation taking place in the intestines, especially the small intestine (where you do not want this happening). Although everyone is different, so you may experiment by adding in low amounts of resistant starch and see how it reacts with your body before introducing more.
How to Safely add Resistant Starch to Your Diet
Resistant starch can be obtained either through food or supplements. Most common food sources include:
- Retrograded potatoes (cooked and then cooled such as fermented potatoes)
- Green bananas
- Plantains
- Legumes (cooked and cooled)
- Parboiled rice (including wild rice)
Supplement sources include:
- Potato starch, NOT potato flour (where to find)
- Plantain flour (where to find)
- Green banana flour (where to find)
- Cassava starch/tapioca (where to find)
- HI-MAIZEⓇ Flour (not cornmeal, cornflour or cornstarch)
Note: arrowroot is not high in the resistant type of starch, contrary to popular belief. On the other hand, teff, a lesser-known but extremely nutritious gluten-free grain, is high in resistant starch.
Potato starch and more recently, banana flour are probably the most common and researched resistant starch supplements, although any of these can be used. Remember, although these foods are starches, they are not being absorbed so they are not contributing to your daily carbohydrate consumption nor are they a significant source of calories. There is also no need to worry about spikes in blood glucose or insulin with these starches either.
One tablespoon of retrograded potato starch contains 8 grams of resistant starch and is very economical as a supplement source. Start small with a 1/2 tablespoon and slowly work your way up allowing several days to a week before increasing consumption to know how your body reacts with the introduction. You can mix this with other food, or in water alone. Some gas and bloating can be expected but should subside over time. When side effects are stabilized, you can safely work your way up to 30 grams of resistant starch. Note, that for some this may be too much to handle, so go at your own pace. If symptoms persist, this may be a sign that you may have other intestinal issues present.
Most healthy people will tolerate resistant starch just fine if slowly introduced, and will eventually start to see some great benefits from regular use. It may take some time (a few weeks) until you can notice health improvements as your body adapts to the starch and converts it over to the usable short-chain fatty acids.
References
(1) Gut bacteria’s fatty acid boosts immune system, reducing inflammation
(2) Promise for Improving Human Health
(3) A promising dietary agent for the prevention/treatment of inflammatory bowel disease and bowel cancer
I, too, wonder how the process of retrograding works. Please could anyone answer!
Could I cook several batches of potaoes or white rice and cool it down directly. Then reheat in portions as I need it and eat it hot? Or do I need to eat is cold?
And what about baking with tapioca or plantain?
I would like to use the RS in whole foods and not take a supplement.
Thank you all!
Thanks Carla. You are incorrect — raw RS2 is vastly different from RS3 both in physical, biochem and gut flora effects in human trials.
RS2 at high dosages has several problems — it worsens the MetSyn gut profile by lowering all the anti-inflammatory gut flora and the gut hormone known for fat burning, GLP-1. RS2 only provides energy for the ‘bottom feeders’ in the gut, not the human species that are special to H. sapiens.
http://drbganimalpharm.blogspot.com/2014/12/new-bulletproof-podcast-with-dave.html?m=1
RS3 (cooked-crystallized) resistant starch is what humans and our ancient hominid cousins adapted to by cooking and routine use of fire.
http://drbganimalpharm.blogspot.com/2014/12/paleo-mag-hot-tony-federico-has.html?m=1
The gut researchers have concluded that the rodent/hamster studies for RS2 do not apparently translate to humans for benefits of metabolisms, fat loss or insulin/glycemic control. It appears for really dysbiotic guts, RS2 causes fatty organs, increases fat mass and raises insulin resistance.
“In rodents, data suggest that chronic RS
feeding upregulates proglucagon expression (i.e. GLP-1
precursor) in the colon with concomitant increases in
neuropeptide expression in the hypothalamus (Shen et
al., 2009; Zhou et al., 2008). These effects result in weight
loss and improvements in glycaemic control.
However, to date there is no evidence for this in humans” (Geurts et al, 2014)
Grace Liu is mistaken. There are more than 70 human clinical trials with RS2 from high amylose corn and about ten clinical trials with RS3. RS2 from high amylose corn is available in the food industry and from King Arthur Flour as Hi-maize natural fiber. It has specifically been shown to significantly improve insulin sensitivity (by up to 54%), gut health, laxation, stops diarrhea when added to oral rehydration solutions, reduce protein-based toxins in the blood when given to patients with kidney diseases, increase satiety, help people eat less food. People have consumed 100 grams of resistant starch from high amylose corn without ill effect – it actually significantly improved insulin sensitivity in healthy people at that dose.
Animal studies show that RS3 ferments differently than RS2, but not enough human studies have been published which show differences in fermentation patterns and health benefits. RS3 from tapioca has the most studies, but potato has 2 human clinical studies that I know of.
See resistantstarch.us for the science behind resistant starch. The overall body of evidence is tremendously strong with RS2 from high amylose corn and simply skimpy for other sources. Get the facts!
Might be more convincing if you noted your conflict of interest, as I assume, judging from your LinkedIn page, that King Arthur or a similar concern is a client of yours. Then again, this kind of sounded like a commercial.
I love to eat ripe,sweet platains.Problem is that they make me flatulent.What could be causing this?And what should I do to correct this?
Does this information change anything in the GAPS diet?
If the food is has been retrograded, then yes these are significant sources, but if cooked normally or store bought than no. Supplements can just be an easier way for people to reap the benefits immediately in concentrated amounts.
How is a potato retrograded?
“Retrograded” simply means cook a potato, let it cool off in the fridge, then eat. You can eat it cold from the fridge, or re-heat it: once it has reached fridge temperature once, it has “retrograded”, and reheating it will not damage that nice “retrograded” quality.
So, eat previously cooked and cooled potatoes (or previously cooked and cooled rice, same idea).
For RS Type 3 – After retrogradation- when starches are cooked and then immediately cooled, does the resistant starch survive reheating or must it be eaten cold?
Jim
Hate to show my ignorance, but I have never heard of the retrograde process..Can anyone explain it in a “Retrograding for Dummies” manner? Thanks!
Retrograde is when starches are cooked and then immediately cooled, such as parboiled rice. It allows for starched to still be indigestible.
So what would that look like for cooking potatoes? Sorry, I need a “Retrograding for Dummies” manual also! And does that mean the food should be consumed cold? Thanks!
Plants store energy in the form of starch, which is made of chains of glucose. Within the plant, they are packed into dense little granules. Raw, unprocessed whole grains have a lot of RS2 and RS1 resistant starch.
Cooking starch in the presence of water makes the granules swell, and some of the glucose chains leak out. This causes thickening as the granules are now bigger and glucose chains are floating around. If they are cooked long enough, the granules will burst, releasing all of the glucose chains. This is why gravy does not maintain its thickness on buffets – the additional heat required to keep food warm finishes cooking out the starch.
When potatoes or rice are cooled down again, the glucose chains are attracted to each other and can form weak bonds with each other. This is what retrogradation actually is. For instance, an uncooked potato is 80+% resistant starch, but a hot baked potato contains very little. If that hot baked potato is allowed to cool (without mixing in sour cream, butter, etc, which interferes with retrogradation), one study found about 12% resistant starch had formed. It’s low, but it’s there. If the potato is heated up again, some of these weak bonds break and there is less resistant starch, but if it is cooled down again, you’ll end up with slightly more resistant starch than 12%. That means there is still a lot of digestible starch, which you may or may not want. There is not a lot of data that is trustworthy as the analytical methods to measure resistant starch have been changing over the past decade.
I’ve built resistantstarch.us to explain the scientific data, with lots of references to the publications. The data is really very strong – more than 100 published human clinical trials showing strong benefits.
What about people who are avoiding nightshades due to inflammatory conditions? Would potato starch react differently in the body than other nightshades when used in this way?
Not in my experience, it has a much different reaction than a fully cooked potato, but you can still be cautious by adding in a little at a time as directed in the article.
Here is an interesting article about RS1, RS2 and RS3.
Cooked/Crystallized RS3 Trumps Raw RS2: They are Vastly Different for Our Guts
Update ~ RS2 and RS3 are Not Exactly the Same Thing
http://drbganimalpharm.blogspot.com/2014/06/contupdate-2-rs2-and-rs3-are-not.html?m=1
I’ve written before about my Mom’s decades long struggle with IBS (mostly resolved in the past 10 years due to some diet changes and supplementation with therapeutic grade probiotics and fermented cod liver oil), but when her IBS was at its worst, I remember she always loved green bananas (which I don’t enjoy at all .. I like them ripe)! Perhaps this was a sort of self medication on her part with food and resistant starch in particular to help with the IBS.
Hi Sarah
Which article was it that wrote about your mom’s recovery from IBS? I would love to read this, as I am dealing with IBS.
Thanks, Renee