Resistant Starch: A Powerful Ally for Gut Health

What Is Resistant Starch?

Resistant starch (RS) is a class of carbohydrate that, unlike ordinary starch, is not broken down in the small intestine and reaches the large intestine undigested. There it acts as a fermentable prebiotic fibre — food for beneficial colon bacteria (Topping & Clifton, 2001).

There are four main types of resistant starch:

Butyrate — Why Does It Matter So Much?

When resistant starch is fermented, Bifidobacterium and Roseburia species produce butyrate — a short-chain fatty acid that is among the most thoroughly documented dietary compounds for gut health:

• Primary energy source for enterocytes — fuels colon mucosal cells
• Anti-inflammatory action — inhibits the NF-κB signalling pathway
• Colorectal cancer prevention — induces apoptosis in cancer cells
• Improved insulin sensitivity — enhances cellular glucose uptake
• Stronger intestinal barrier — increases tight junction expression (Canani et al., 2011)

Resistant Starch and Blood Sugar

Resistant starch has a meaningful impact on glycaemic response:

1. Lower glycaemic index — RS-rich foods raise blood glucose more slowly
2. Second meal effect — RS consumed at breakfast reduces the glycaemic response to lunch (Robertson et al., 2005)
3. Reduced insulin resistance — regular RS consumption improves insulin sensitivity

This makes resistant starch interesting for both diabetes prevention and body weight regulation.

Best Food Sources of Resistant Starch

Foods with the Highest RS Content:

1. Green (unripe) bananas — 15–19 g/100 g
2. Raw potatoes — 11–12 g/100 g
3. Cooled cooked potatoes — 3–6 g/100 g (retrograde RS)
4. Cooled cooked rice — 2–5 g/100 g
5. Beans and lentils — 2–5 g/100 g
6. Raw oats — 3–4 g/100 g
7. Plantain — up to 16 g/100 g

Key Tip: Cooling Increases RS Content

Cooling potatoes, rice, and pasta after cooking converts some digestible starch into retrograde RS (RS3). Research shows cooled and reheated potato has a significantly lower glycaemic index than freshly cooked potato.

Resistant Starch Supplements

The most popular RS supplements include:

• Green banana flour — high RS2 content
• Potato starch — affordable and effective RS2 source (approximately 8 g RS per tablespoon)
• Psyllium-based products — rich in soluble fibre compounds

ICONFIT Superfoods Organic Psyllium Husk Powder 150g is an excellent soluble fibre source that complements the prebiotic effect of resistant starch. Psyllium itself is not RS, but both support the gut microbiome via different mechanisms.

Find fibre and prebiotic supplements at maxfit.ee's fibre category.

How to Consume Resistant Starch?

• Start slowly — 5 g/day and increase over 2–3 weeks to 15–30 g
• Increasing too fast can cause bloating and gas
• Potato starch can be stirred into yoghurt, smoothies, or cold oats
• Green bananas can be blended into smoothies

FAQ

Does resistant starch boost metabolism?

There is no direct evidence for a metabolism-boosting effect. However, RS reduces post-meal glycaemic swings, which helps control food cravings and prolongs satiety — indirectly supporting healthy weight management.

Does heating destroy resistant starch?

Yes — cooking breaks down the RS crystal structure. This is why cooked potato contains less RS than raw potato. Cooling restores some RS as retrograde starch (RS3). Cooled-and-reheated food therefore has higher RS content than freshly cooked food.

Is resistant starch suitable on a keto diet?

This is individual. In theory, the carbohydrates in RS (which are not digested) should not affect ketosis, but in practice some RS sources also contain digestible carbohydrates. Potato starch is one of the purest RS sources with minimal digestible carbohydrate.

References

1. Topping, D. L., & Clifton, P. M. (2001). Short-chain fatty acids and human colonic function: roles of resistant starch and nonstarch polysaccharides. Physiological Reviews, 81(3), 1031–1064.
2. Canani, R. B. et al. (2011). Potential beneficial effects of butyrate in intestinal and extraintestinal diseases. World Journal of Gastroenterology, 17(12), 1519–1528.
3. Robertson, M. D. et al. (2005). Insulin-sensitizing effects of dietary resistant starch and effects on skeletal muscle and adipose tissue metabolism. American Journal of Clinical Nutrition, 82(3), 559–567.
4. Birt, D. F. et al. (2013). Resistant starch: promise for improving human health. Advances in Nutrition, 4(6), 587–601.