I would be surprised if you haven’t heard something about resistant starch lately. It has become a hot topic in the world of nutritional science, particularly with regards to gut health. So what is resistant starch? Does it play a role in gut health and IBS? What are the food sources? Let’s take a look!
What is Resistant Starch?
Resistant Starch (RS) is a type of fibre that we cannot digest. So basically as it sounds – starch which resists digestion. Below are the four types of RS, each of which have distinctive properties.
Found in legumes, seeds and wholegrains. RS1 resists digestion due to its physical properties (e.g a protective coating).
Found in unripe bananas and green potatos (yum…). RS2 resists digestion intrinsically prior to cooking.
RS3, AKA retrograded starch, resists digestion due to physical changes that occur during retrogradation. Retrogradation occurs when foods are cooked and then cooled. Therefore RS3 is found in foods such as cold cooked potatos and rice.
RS4 is chemically modified to resist digestion, particularly for use in processed foods.
Once RS reaches the large intestine, it acts as fuel for gut microbiota (bacteria). This makes RS beneficial for good gut health, in addition to a few other proposed health benefits.
Health Benefits of RS
RS has been associated with a few other key health benefits, such as:
- Blood glucose control and insulin regulation (particularly important for those with Diabetes).
- Satiety – AKA feeling of fullness after a meal. Improved satiety is associated with weight management and/or weight loss.
- Decreased risk of colon cancer
Whilst RS is beneficial for gut health due to its role in fuelling gut microbiota, it may potentiate problems for those with Gastrointestinal (GI) issues, such as Irritable Bowel Syndrome (IBS). But if RS is beneficial for gut health, shouldn’t it be beneficial for all individuals with GI issues? RS is beneficial for the gut bacteria of all individuals, including those with GI issues. However, as large quantities of RS may worsen IBS symptoms in some individuals, it is important to individualise intake.
Impact of RS on GI Conditions
RS behaves much like soluble, fermentable fibre. Similar to RS, fermentable fibre can be a culprit for worsening IBS symptoms in some individuals, due to increased gas production. Whilst RS may worsen symptoms in some individuals, it still promotes healthy gut bacteria – which is extremely important in IBS. This means quantity becomes key – as everyone has different tolerance thresholds.
So even if you find large quantities of RS trigger symptoms, it is still important to include some low FODMAP RS sources in the diet. Some low FODMAP sources of RS include:
- Green (unripe) bananas
- Cooked, then cooled potato, rice and gluten-free pasta.
- Oats (particularly soaked overnight), barley and sorghum.
- Low FODMAP serves of lentils (1/4 cup chickpeas, ¼ cup butter beans, or ½ cup tinned lentils).
If you are planning on altering your intake of RS (or other key nutrients), ensure this is done under the provision of an Accredited Practising Dietitian (APD).
- Alfa MJ, Strang D, Tappia PS, Graham M, Van Domselaar G, Forbes JD, Laminman V, Olson N, DeGagne P, Bray D, Murray BL. A randomized trial to determine the impact of a digestion resistant starch composition on the gut microbiome in older and mid-age adults. Clinical Nutrition. 2017 Mar 31.
- Gong L, Cao W, Chi H, Wang J, Zhang H, Liu J, Sun B. Whole cereal grains and potential health effects: Involvement of the gut microbiota. Food Research International. 2018 Jan 31;103:84-102.
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