The Lowdown on Resistant Starch

You are likely already familiar with starch, the type of carb found in foods like bread, pasta, rice etc. But have you heard of resistant starch? 

Resistant starch is a type of starch that, unlike other starches, is not digested and absorbed in the gut. Instead it passes directly into the large intestine where it is fermented by your friendly gut bacteria to produce beneficial compounds called short chain fatty acids.

Four types of resistance starch:

  • RS1 - This type is physically inaccessible by digestive enzymes. Sources include coarsely milled or intact whole grains, legumes and durum wheat pasta 
  • RS2 - This type is indigestible in raw foods but becomes more digestible when cooked. Sources include some legumes, unripe green bananas, raw potatoes, and high-amylose starches like corn 
  • RS3 - This type is formed in foods that are cooked and then cooled. Sources include cooked and cooled bread, potatoes, pasta, and rice
  • RS4 - This type is a chemically modified starch. Sources include thickening agents found in processed foods 

What does resistant starch do?

Resistant starch passes undigested into your large intestine, where, like fibre, it acts as a food source for the good gut bacteria that live there. These bacteria ferment resistant starch and produce short chain fatty acids which provide a host of health benefits to the body. Some potential benefits [25331334] which have been attributed to resistant starch and effects of short chain fatty acids include:

* Improved bowel health
* Improved blood sugar and insulin control following a meal
* Increased satiety
* Stimulated growth and activity of good bacteria 

Great food sources of resistant starch:

  • Food Resistant starch content (g/100g)
  • Kidney beans, cooked/canned 3.8g
  • Butter beans, cooked/canned 6.4g
  • Black beans, cooked/canned 4.7g
  • Barley, cooked 3.4g
  • Rolled oats, uncooked 7.7g
  • Sourdough bread, wheat 3.3g
  • Banana, unripe/green, raw 2.8g
  • Plantain, ripe, raw 5.1g

 Source [32040399]. 

Written by
Alannah Mezzatesta, BSc
Nutrition Scientist (ANutr)
last updated  27th July 2022