Resistant starch - what it is and why you should include it in your diet?
Resistant starch….what is it? what are the benefits? should you consume it?
Your health is a journey. When you are faced with health issues, finding the source and/or cause and then finding treatment and/or lifestyle changes is important to see what works for you as this would vary from person to person. For me, I suffered from bloating for many years even though I ate healthy foods. I tried probiotics but resistant starch worked better for me than any probiotics or fermented foods…..
For many years I avoided eating carbs as in rice, potatoes, bread. I ate a high protein and fat diet and my only carbs were in the form of vegetables - mainly green veggies and sweet potato and some fruit. Occasionally, I would have some properly fermented sourdough bread with lots of butter on top (yum) but my carb intake overall was very low.
My digestion was ok but never fantastic although I always ate wholefoods. I hardly ever ate anything processed as my body always had trouble digesting it and it always made me feel bad. However, although I was eating wholefoods, I was reacting to something or a few things and over the past year I have made it my mission to find out what was causing it. Through the elimination of certain foods, I have found what foods my body was having trouble trying to digest and I eliminated them from my diet.
I also made it my mission to improve my gut health. When kombucha became popular a few years ago, I started drinking it and then learnt how to make it. Although it helped a lot, my digestion was still not 100%. I tried to incorporate fermented foods, but although many people raved on about how it improved their digestion, it appeared to do the opposite for me. I ended up more bloated and uncomfortable and it did not help my digestion.
Then I heard about resistant starch. I had read about it, knew about its benefits but had not yet tried it and as such did not know how much it would help me.
What is resistant starch?
Resistant starch is starch that when consumed is not broken down by the digestive system. It is resistant to the digestive enzymes. Therefore it moves through the small intestine to the large intestine without being digested (Ref 1).
Starch is a carbohydrate which is composed of glucose molecules. Usually the digestion of starch begins in the mouth where it is acted on by the enzyme salivary amylase to start breaking it down. It then passes through the stomach to the small intestine where it is acted on by pancreatic amylase for further digestion. Resistant starch is the portion of starch that is not broken down by the pancreatic amylase in the small intestine, and therefore reaches the colon which are then partly broken down by intestinal bacteria (Ref 2, 3).
What are the types of resistant starch?
There are 5 types of resistant starch:
Type 1 is usually found in plant cell walls and in whole grains and is hard to access. (Ref 4, 9).
Type 2 is found in raw potato and unripe bananas. It is not able to be broken down by the body as starch is packed tight within the starch granules (Ref 9).
Type 3 is retrograded starch, which forms when cooked starchy foods are cooled (Ref 9).
Type 4 is due to the chemical treatment/modification of starch (Ref 9).
Type 5 is where part of the starch (amylose) forms complexes with fats (and forms an amylose-lipid complex) which makes it more heat stable (Ref 9).
The type of resistant starch which I am referring to is type 3, where starchy foods are cooked and cooled. When these foods are cooled, the starch crystallises making them resistant to digestion and therefore passing through to the large intestine without being broken down.
What are the functions of resistant starch?
Resistant starch is partially fermented in the colon, which leads to an increase of short chain fatty acids (SCFA) (Ref 1 & 4).
Bacteria in the colon ferment the resistant starch and non-starch polysaccharides (which are the major components of dietary fibre) and product short chain fatty acids (SCFA) (these include acetate, propionate and butyrate) (Ref 1, 4, & 5).
SCFA cause a number of changes to the microbiome, physiology of the colon, energy source and intestinal microbiota (Ref 6). SCFA’s help to lower the pH of the bowel (i.e. make it more acidic) which makes it harder for pathogens and ‘bad bacteria’ to grow (Ref 5).
Resistant starch is also a prebiotic which means that it helps to feed the ‘good’ bacteria in our gut (Ref 7). It helps to promote the growth of beneficial bacteria in the large intestine by providing food for the good bacteria in your intestines (Ref 7, 8).
What are the benefits of consuming resistant starch?
For over three decades, many studies have looked at the health benefits of resistant starch in humans and animals, and the results are pretty amazing. Resistant starch has been shown to:
Decrease glycaemic and insulin responses (and therefore has been used in the treatment of Type 2 diabetes). It has been shown to improve insulin sensitivity (Ref 8).
Lower plasma cholesterol and triglyceride levels (i.e. fat) (Ref 8)
Increase satiety (so you feel full and satisfied), and reduces risk of obesity (Ref 1, 8).
Resistant starch feeds the good bacteria in our large intestine.
While the ‘good’ bacteria grows and multiply from breaking down and consuming the resistant starch, the ‘bad’ bacteria can’t process it at all.
Good gut function is important for our overall health and well being. The gut-brain connection is an important one as it shows that what we eat has a profound effect on how our brain or mind feels and functions.
If our gut is functioning optimally, we are able to extract more nutrition out of our food.
Stronger immune system as our gut also makes up 80% of our immune system.
Helps to increase fecal bulk due to increased starch intake (Ref 4)
Increase absorption of important minerals like calcium and magnesium (Ref 8).
Decrease absorption of toxic and carcinogenic compounds (Ref 8)
What are the sources of resistant starch?
Cooled rice and cooled potatoes are excellent sources of resistant starch (Ref 9).
When cooking a rice dish or potatoes, cook it and leave it to cool before eating it or leave it to eat it the following day.
It has been shown that even if rice is cooked, cooled and reheated, it has more resistant starch in it.
Examples include cold potato salad, cold rice salads (Ref 6).
Other sources include raw potatoes, green bananas, green plantains (I haven’t gone this far but it is well worth a try!!)
I try to ensure I eat some resistant starch with every meal (or at least everyday) to help with my digestion and to feed my gut bacteria. Since I have been doing this, my digestion has improved so much and I am hardly ever bloated. For me this was the missing piece to the puzzle - after I had eliminated foods which I reacted to (including dairy and nuts).
For more information on this topic, or for information on how to heal your gut, elimination diets, fermented foods, then comment below or send me a message.
Thanks for reading this far!!
2. Evange´ lica Fuentes-Zaragoza, Elena Sa´ nchez-Zapata, Esther Sendra, Estrella Sayas, Casilda Navarro, Juana Ferna´ ndez-Lo´ pez and Jose´ A. Pe´rez-Alvarez. Resistant starch as prebiotic: A review. IPOA Research Group, Agro-Food Technology Department, Universidad Miguel Herna´ndez, Orihuela, Alicante, Spain. 2011
3. Kaiser, S. 2018. What are the steps to digestion for carbohydrates? https://healthyeating.sfgate.com/steps-digestion-carbohydrates-4053.html
4. The National Academy of Sciences, Engineering, Medicine. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (2005). https://www.nap.edu/read/10490/chapter/9#347.
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6. David Ríos-Covián, Patricia Ruas-Madiedo, Abelardo Margolles, Miguel Gueimonde, Clara G. de los Reyes-Gavilán, and Nuria Salazar. Intestinal Short Chain Fatty Acids and their Link with Diet and Human Health. Front Microbiol. 2016; 7: 185. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4756104/
8. Wells, K. Resistant Starch: Gut Superfood. 2018. https://wellnessmama.com/17005/resistant-starch-gut-superfood/
9. Reynante Lacsamana Ordonio and Makoto Matsuoka. Increasing resistant starch content in rice for better consumer health. PNAS November 8, 2016 113 (45) 12616-12618; published ahead of print October 28, 2016. https://doi.org/10.1073/pnas.1616053113