Resistant starch RS1

Resistant starches

Starch trapped in a structure that digestion does not open: whole grain, intact seed, uncrushed legume.

Milling is what destroys it: the same grain reduced to fine flour no longer provides any.

Effects and benefits

The starch that makes the whole journey. Locked inside a whole grain or an intact lentil, it escapes digestion and reaches the colon, where your bacteria turn it into butyrate, the favorite fuel of the cells lining it. Along the way, it softens the rise in blood sugar after a meal.

In the small intestine, enzymes can only attack what they reach. The walls of intact plant cells form a cage: as long as they hold, the starch stays inside. That is why whole or cracked grains raise blood sugar less than the same amount of fine flour (Jenkins et al., 1988).

Replacing digestible starches with resistant starch in a meal contributes to a reduction in the blood glucose rise after that meal, provided it makes up at least 14% of total starch (Regulation 432/2012).

Once in the colon, it is fermented slowly, and what comes out is mostly butyrate: the cells lining the colon draw most of their energy from it, up to 70% (Roediger, 1982). The rest becomes propionate and acetate, used by the liver and muscles.

There is no recommended intake for resistant starch; a Western diet provides a few grams a day, several times less than in rural Africa or India (Birt et al., 2013). For fiber in general, the benchmark is 25 g a day for an adult according to EFSA, 30 g according to ANSES.

Sources: Jenkins et al., BMJ, 1988 · Roediger, Gastroenterology, 1982 · Birt et al., Adv Nutr, 2013 · EU Regulation 432/2012 · EFSA, 2010 · ANSES, 2016

Where to find it (54)

Its category: Resistant starch