Key Message: Resistant starch plays an important role in our diet and helps maintain intestinal health
Action Point: Choose whole, unprocessed sources of carbohydrates such as wholegrains, fruits and vegetables, beans and legumes
Resistant starch (RS) plays an important role in our diet. It is a type of starch that isn’t fully broken down and absorbed in the small intestine, but rather turned into short-chain fatty acids (SCFA) by intestinal bacteria. SCFAs can be absorbed into the body from the colon or stay put and be used by colonic bacteria for energy.
The amount of SCFAs we have in our colon is related to the amount and type of carbohydrate we consume. And if we eat plenty of RS, we have plenty of SCFAs. But the most important of these SCFA’s is butyrate, which is actually the preferred fuel of the cells that line the colon. So, by increasing the amount of butyrate, resistant starch feeds both the friendly bacteria and indirectly feeds the cell in the colon. 1
What makes a starch “resistant”?
Most of the carbohydrates in our diets are starches. All starches are composed of two types of polysaccharides: amylose and amylopectin.
Amylopectin is broken down quickly, which means it produces a bigger rise in blood sugar (glucose) and subsequently, a large rise in insulin. Examples are waxy rice, maize and potato starch.
Amylose predominates in RS. Foods high in amylose are digested more slowly and are less likely to spoke blood glucose or insulin. Examples are beans and other legumes.
Not all the starch we eat gets digested and it is therefore resistant to digestion. We call this resistant starch,which acts like soluble fibre.
What are the health benefits of resistant starch?
Eating foods rich in resistant starch nourishes your gut bacteria, which helps maintain intestinal health and reduces the risk of developing colorectal cancer. Many studies have shown that resistant starch can have powerful health benefits. These include improved insulin sensitivity, lower blood sugar levels, reduced appetite and various benefits for digestion. 2 It can also improve immunity and minimize tooth decay.
Where is resistant starch found?
Resistant starch is found in many whole plants foods, but the preparation method has a major effect on the amount of resistant starch in food.
An example of the amount of RS in foods is below. We have found huge variances in the reported levels of RS across all our sources. What we do know is that these foods have higher levels than most!
| Food | Approx Resistant Starch (per 100 g) |
| Potato, steamed, cooled | 6 g |
| Cashew nuts | 19 g |
| Bananas, ripe | 5 g |
| Oats, cooked | 0.2 g |
| Oats, rolled, uncooked | 11 g |
| Potato, roasted, cooled | 19 g |
| White beans, cooked/canned | 4 g |
| Lentils, cooked | 3 g |
How much should we consume?
We might see some benefits from as little as 6-12 grams/day of RS, but closer to 20 grams/day might be ideal. This is easy to get if you eat plenty of whole plant foods.
Data suggests that RS is safe and well tolerated up to 40-45grams per day. Consuming more than this may result in digestive problems such as diarrhoea and bloating. Resistant starch seems to be tolerated best when it is in solid form, is consumed as part of a mixed meal and its consumption is increased gradually over time.
Conclusion:
To get the most from resistant starch, choose whole, unprocessed sources of carbohydrate such as whole grains, fruits, vegetables, and beans/legumes.
References
- Gunnars, K (2014) “Resistant Starch 101 – All you need to know” Authority Nutrition Website. Accessed on 9 September 2015 at http://authoritynutrition.com/resistant-starch-101/
- Nugent, A. P. (2005), Health properties of resistant starch. Nutrition Bulletin, 30: 27–54. doi: 10.1111/j.1467-3010.2005.00481.x
- Andrews, R (2015) “All about Resistant Starch”. Precision Nutrition blog. Accessed online on 9 September 2015 at http://www.precisionnutrition.com/all-about-resistant-starch
- CSIRO Website “ The Hungry Microbiome” Accessed online 9 September 2015 at http://www.csiro.au/hungrymicrobiome/food.html
- Saxelby, C (2014) “Resistant Starch: The newest Fibre” Foodwatch. Accessed online on 9 September 2015 at http://foodwatch.com.au/blog/carbs-sugars-and-fibres/item/resistant-starch-the-newest-fibre.html
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Written by: Sandra Di Giacomo |
