Different foods have different concentrations of resistant starch. For 100 g of dry substance, white bread has 1 g of resistant starch, rice – 4 g, dried peas – 5 g, lentils – 9 g, potato – 5 g, beans – 18 g.

Those who think that the resistant starch it’s a blight for body are wrong. And here it seems that the Creator had a good idea for us: starch with an increased fraction resistance content has a lower glycemic index, it creates a smaller increase of glycemia, than easily digestible starch. This is why beans, with 18 g of resistant starch per 100 g of dry substance, so advisable for diabetics, increases much less the glycemia.

The third type of resistant starch is retrograde.

When the starch has boiled in the water, the granules gelatinizes and swell. In particular the amylose is brought into solution easily, while amylopectin remains in the swollen structure the starch granules.

During the cooling, occurs amylose recrystallization, ie relegation, resulting in a digestibility decrease. Any starch has the relegation potential, but the bigger the amylose content, the easier relegation occurs, resulting in more resistant starch.

But what happens to the resistant starch which could not be digested by the small bowel?

Here we must register the second nutritional advantage – the resistant starch is fermented in the large bowel.

The diverse and numerous microflora in the colon ferments the unabsorbed  carbohydrates, ie the starch that resisted to digestive enzymes in the small bowel, in fatty acids with short chains: acetic, propionic and butyric, as secondary products resulting hydrogen, carbon dioxide and methane. Short chained acids are absorbed immediately, so the unabsorbed energy from the small bowel is not lost.

The energy value of food fibers is 2 kcal (8.3 kJ) per gram. A similar amount has the resistant starch. The butyric acid or butyrate resulted from the resistant starch fermentation supports the health of the large bowel, acting as a preferred energy source for intestinal mucosal cells.

But there are more other advantages. The resistant starch, being the necessary substrate of intestinal flora, favors the bacterial conversion of the bile acids, which have escaped the small bowel reabsobrtion being converted into secondary bile acids (deoxycholic and lithocholic) protecting the intestinal mucosa from prolonged contact with bile acids and this way protecting against the risk of cancer.

Finally, the resistant starch is the bacterial flora food useful in the colon. Sufficient amounts of resistant starch make the large number of bacteria to not allow the development of pathogens germs who broke into the digestive tract.

So we don’t have to avoid any potatoes or beans. Our body needs the resistant starch.

Categories: Diet, Health, Nutrition

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