Episode 51 – Resistant Starch

Key Topics Covered

What is resistant starch and why should we care about it? 

  • It is a form of starch/fibre that passes through both the small intestine and large intestine mostly undigested. 
  • It acts as a prebiotic fibre. Even though it passes through mostly undigested, it still is a food source for bacteria in the large intestine. 
  • It increases the amount of short chain fatty acids in the gut too. And these are typically associated with good gut health. In particular it increases butyrate which is often linked with positive outcomes. 
A healthy gut filled with fiber rich foods

What is it found in and how much do people eat? 

  • Pretty much all starchy foods contain some amount of resistant starch. But it is particularly found in unripe bananas, legumes, and cooked and cooled potato/pasta/rice 
  • The average person appears to get 3-9g of resistant starch per day  
  • Whereas the benefits of resistant starch seem to be best at 15-20g per day. 

There are a lot of benefits associated with a higher intake of resistant starch  

  • Improved gut health/diversity of gut microbiome.  
  • Reduction in insulin resistance
  • IBS symptoms
  • Weight loss
  • And few other things which we will go over one by one.  

1. Insulin Resistance

  • High intake of resistant starch has been associated with a 33-50% reduction in insulin resistance. 
  • In the short term it reduce BGL’s due to being resistant to digestion and also slowing the uptake of glucose. But in the long term, it theoretically improves insulin resistance due to some downstream effects of increased short chain fatty acids (SCFAs) (↓circulating fatty acids = ↓ insulin resistance) 
  • We’ll discuss shortly, but it also potentially helps with weight loss. Which as we’ve seen in the research, has its own benefits on improving insulin resistance.

2. IBS Improvements

  • As mentioned, resistant starch increases SCFAs, particularly butyrate.  
  • It also increases bifidobacteria, which is a group of bacteria commonly associated with good gut health. 
  • People with IBS on average have 5x lower levels of bifidobacteria. So theoretically, resistant starch could help. 
  • I would also caution against a dramatic increase in fibre, since that could increase gas/bloating. 
  • FODMAPs that are often also found in these plant based foods may also be something else to consider although – rice, potatoes and unripe bananas would be great Low FODMAP sources of resistant starch.
  • Just to preface though, just because someone has IBS doesn’t mean they have poor gut health. This approach may work for some, but not all.

3. Weight Loss 

  • Carbs normally have 4kcal/g, whereas resistant starch has 2kcal/g. So that can be a small factor, whereby you’re consuming half the amount of calories for the same amount of food that you’re eating.
  • But, the bigger factor is that people with higher resistant starch intake typically consume fewer total calories per day. 
  • Appetite management is the biggest factor that is proposed to explain this. 

4. Other stuff  

  • Resistant starch has early links with reduced cases of bowel cancer, inflammatory bowel disease and diverticular disease.  But it is super early in the research though, so it is hard to make strong claims about any of that. 

Practical takeaway 

  • Do we do anything with this in practice with our clients? 
    • We don’t go out of our way to mention it, as we’ve identified that many of our clients are incidentally consuming relatively high amounts anyway.
  • While these benefits are nice, it is clearly not a top priority. 
  • I’d focus on doing things that help, without having to stray too far from your nutritional priorities. 

For example: 

  • Focusing on legumes, seeds and/or wholegrains. 
  • Potentially having cooked and then cooled potato/rice. 
  • Maybe having less ripe bananas, if you like them that way. 
  • Consider having a product like BARLEY+ protein at breakfast. 

Relevant Links/Resources

Studies Mentioned

Relevant Resources

Related Blog Posts