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Resistant starch facts and foods

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It’s a nutrient that’s often mentioned in the same sentence as ‘gut health’ but what exactly is resistant starch? Which foods deliver the largest hit? And how much should you be eating, anyway? Here’s what you need to know.

Gut health is big these days – and for a big reason. Your mood, sleep quality, stress levels, immune system and even how likely you are to maintain a healthy weight, can all be affected by how healthy and happy your gut is, or isn’t. 

And while a few different foods and lifestyle factors can help support your gut health, resistant starch plays a key role.

What is resistant starch

Resistant starch is a dietary starch that has fibre-like qualities, because, as its name suggests, it resists digestion in the small intestine. 

This allows it to pass through to the large intestine unscathed, where it acts as a prebiotic, encouraging ‘good’ bacteria like Bifidobacteria and Lactobacilli to grow. It also feeds the gut’s resident population of bacteria, which ferment and break it down into a few different healthy fatty acids. 

One of those is a fatty acid called butyrate. Because it’s the preferred fuel for the cells that line the gut, butyrate is vital for helping the gut to stay healthy and function normally. 

But, butyrate has a number of other health benefits, too, including helping to maintain healthy cholesterol levels and even being able to potentially boost weight loss

Foods that are high in resistant starch

All starchy foods contain a certain amount of resistant starch, but the best sources are:
  • Wholegrain cereals, such as uncooked oats. 1/4 cup uncooked rolled oats contains 4.4g of resistant starch, while 1 cup of cooked oats contains only 0.5g of resistant starch.
  • Legumes, including lentils, kidney beans and chickpeas. ½ cup of cooked lentils contains 3.4g of resistant starch
  • Firm, slightly under-ripe bananas. 1 medium banana contains 4.7g of resistant starch.
Resistant starch also forms when some types of starchy foods are cooked then cooled, because this allows some of the starch molecules to recrystalise.

So, while cooked rice, pasta and potatoes naturally contain a small amount of resistant starch, levels increase when they’re allowed to cool before being eaten.

To make it work, think sushi and pasta and potato salads. It’s the same story with legumes – allow them to cool down after you’ve cooked them from scratch, and their resistant starch content climbs even higher.

Are you eating enough resistant starch?

An official adequate or recommended dietary intake hasn’t yet been established for resistant starch, but some experts advise eating between 15 and 20 grams of it per day, for bowel health. CSIRO research suggests that Australians are falling well short of that mark, only eating around three to nine grams of resistant starch each day, on average.

To bump up your intake, try this resistant-starch-rich menu: