Some of you who are trying the low Fodmap diet, may not have had complete success with eliminating your symptoms. If that is the case, there are various things for you to look at and one of them is resistant starch. Today’s video will explain what it is, how it may be affecting your digestive system and what to do about it.
Today I want to talk to you about the part that resistant starch could be playing in your symptoms. If your symptoms are continuing even though you feel you have put everything else into place with this diet, then it is time to look at resistant starch.
Resistant starch resists digestion and passes through to the large intestine where it acts like dietary fibre. This is now thought of as the third type of fibre alongside soluble and insoluble fibre.
Let me explain a little about the two starches, amylopectin starch and amylose starch.
Amylopectin starch is easy to digest and absorb. It gelatinizes (absorbs water) easily when heated in water. Gelatinized starch is easier to digest. The digestive enzyme, amylase, can quickly break down amylopectin into glucose, which is absorbed rapidly.
On the other hand, amylose starch is more difficult to digest and absorb. It is more difficult for it to gelatinize making digestion by amylase enzyme difficult. In general, foods that contain more amylopectin (higher glycemic index), such as jasmine rice, short grain sticky rice (also known as glutinous or sushi rice) as well as some varieties of potatoes, such red waxy ones, are much easier to digest and absorb than foods containing more amylose (lower glycemic index), such as basmati rice, most long grain rice (except for jasmine), pasta, most wheat, corn, oat and barley products, most potatoes and bananas. The wheat and barley don’t concern us anyway because they are high Fodmap, but the others may concern us. As you can see this doesn’t bode well for those of you who should be on a low glycemic index diet.
Resistant starch has been categorized into four types:
- RS1 – Physically inaccessible or indigestible resistant starch, such as that found in seeds or legumes and unprocessed whole grains.
- RS2 – Resistant starch that occurs in its natural granular form, such as uncooked potato, green banana and high amylose corn.
- RS3 – Resistant starch that is formed when starch-containing foods are cooked and cooled, such as legumes, bread, cornflakes, potatoes or pasta salad. This occurs due to retrogradation, which is when dissolved starch becomes less soluble after being heated and dissolved in water and then cooled. I will talk about this again in a moment.
- RS4 – Starches that have been chemically modified to resist digestion. This type of resistant starch can have a wide variety of structures and are not found in nature.
Let’s go back to RS3 resistant starch, the one that occurs when certain starch-containing foods are cooked and cooled and something called retrogradation happens.
Retrogradation is a reaction that takes place in gelatinized starch when the amylose and amylopectin chains realign themselves, causing the liquid to gel.
When native starch is heated and dissolves in water, the crystalline structure of amylose and amylopectin molecules is lost and they hydrate (that is take in water) to form a viscous solution, which is fine for us but if the viscous solution is cooled or left at lower temperature for a long enough period, the amylose and amylopectin molecules retrograde and rearrange themselves again to a more crystalline structure, which they had at the beginning and that’s what makes these foods hard to digest.
So to summarize, if you think resistant starch may be your issue, avoid bananas, corn and corn starch, oats, frozen green peas, cold pasta, cold potato, long grain rice except jasmine, Basmati rice, most potatoes except red waxy ones, seeds and nuts. And avoid cooling and then reheating starches.