Resistant starch is a carbohydrate that is resistant to digestive enzymes and passes unchanged into the large intestine. It is a breeding ground for the development of beneficial intestinal bacteria and has many he alth-promoting functions.

Starch , a carbohydrate composed of glucose monomers, has for many decades been considered a fully digestible food ingredient if it has been cooked. It is now known that certain fractions of starch calledresistant starchpass through the gastrointestinal tract into the large intestine unchanged or almost intact.

Benefits of consuming resistant starch include: reducing the risk of developing colorectal cancer, lowering blood sugar and cholesterol levels, and better absorption of minerals from food.

Contents:

  1. Resistant starch - what is it?
  2. Resistant starch as a fiber
  3. Foods rich in resistant starch
  4. Resistant starch - he alth properties
  5. Resistant starch - role in slimming diets

Resistant starch - what is it?

Resistant starch owes its name to the fact that it is not digested by gastrointestinal enzymes and is not absorbed in the small intestine. It is one of the components of dietary fiber. The resistance of raw potato starch to the action of amylolytic enzymes was first announced in 1937 by Polish scientist Franciszek Nowotny. The topic was revisited 40 years later, when Japanese researchers obtained similar results.

There are four types of resistant starch (RS):

  • RS1 - physically unavailable; starch contained in undamaged plant cells, e.g. whole cereal grains. It is indigestible in the digestive tract because it lacks enzymes that break down plant cell walls. It passes through the small intestine intact.
  • RS2 - raw starch grains (uncleiled) found in some plants, e.g. raw potatoes, unripe bananas, legume seeds.
  • RS3 - Retrograded starch, which is formed in heat-treated and then chilled food products. It is a starch that has glued at an increased temperature, i.e. has become digestible for humans, andthen precipitated in the retrograde process. RS3 is found in chilled potatoes, rice, pasta, cereals and stale bread.
  • RS4 - chemically or physically modified starch.

Resistant starch as a fiber

In the classic sense, insoluble fiber is components of plant cell walls that are not digested in the digestive tract, such as cellulose, hemicellulose and lignin, and soluble fiber is pectin, gum and mucilage.

Currently, resistant starch is included in dietary fiber because consuming it has the same he alth benefits for the human body as consuming other fiber components. Resistant starch has the effect of soluble fiber.

Increases the volume of food, passes through the small intestine in an unchanged form, and when it reaches the large intestine, it is fermented by bacteria of the typeBifidobacteriumandLactobacillus , i.e. probiotic lactic acid bacteria that form the basis of a he althy human intestinal microflora. The benefits of using resistant starch as a prebiotic, i.e. a medium for the proper gut microbiome, are:

  • production by fermentation of volatile compounds: methane and hydrogen as well as short-chain fatty acids, which leads to a lowering of the pH of the large intestine;
  • promoting the growth of beneficial bacteria whose favorable environment is a low acidic pH and elimination of pathogenic bacteria that develop in a neutral and alkaline environment;
  • production of short-chain fatty acids (acetic, propionic and butyric), which are used by the cells of the intestine as an energy and nutrient and improve their functioning;
  • increased absorption of minerals, especially calcium and magnesium;
  • lowering blood sugar and cholesterol;
  • reducing the risk of developing colorectal cancer.
Worth knowing

Foods rich in resistant starch

Resistant starch as an ingredient beneficial to he alth should be consumed daily in an amount of at least 20 g per day. In developing countries, the average amount in the diet is 30-40 g, while in developed countries, including the European Union, we consume on average only 3-6 g of resistant starch per day.

To avoid unpleasant gastrointestinal ailments such as flatulence, gas and diarrhea, you should not eat more than 50-60 g of resistant starch a day.

The best sources of resistant starch are:

  • beans - 8 g of starchresistant in 1/2 cup,
  • green-skinned banana - 6 g resistant starch in one large fruit,
  • wheat bran - 4.6 g resistant starch in 1/2 cup,
  • cooked lentils - 3.4 g resistant starch in 1/2 cup,
  • potatoes - 4 g resistant starch in 1/2 cup chilled,
  • brown rice - 3 g resistant starch in 1/2 cup chilled,
  • corn - 2 g resistant starch in 1/2 cup,
  • wholemeal bread - 1-2 g resistant starch in 3 slices.

Resistant starch - he alth properties

There has been a lot of attention in recent decades of resistant starch and its potential he alth effects. When consumed in adequate amounts, resistant starch has been shown to contribute to good colon he alth, prevent inflammatory bowel disease, and protect against colon and colon cancer - the world's fourth leading cause of death.

Resistant starch has a lower effect on lipid and glucose metabolism than non-starch polysaccharides, but still plays an important role in lowering blood cholesterol and sugar levels.

The prebiotic and pro-he alth potential of resistant starch is likely to be used in the food industry on a large scale in order to introduce more of this valuable ingredient into the diet of people in highly developed countries.

Resistant starch is metabolized only 5-7 hours after eating a meal, unlike glued starch, the digestion process of which begins immediately after eating.

Protection against colorectal cancer

There is scientific evidence that butyric acid, formed in the gut by the fermentation of resistant starch by bacteria, reduces the risk of cancer in the colon cells.

Studies in rats have shown that a decrease in pH of the intestinal contents and increased production of SCFAs were associated with a reduced incidence of colorectal cancer.

In vitro, butyric acid and its s alts have been shown to play a special role in inhibiting malignant lesions of colon cells.

In people who consume little fiber, doubling this amount reduced the risk of colon cancer by 40%. The best results of butyric acid secretion are achieved by combining insoluble fiber with resistant starch in the menu.

Effect on blood sugar

The presence of resistant starch in food products lowers their glycemic index and reduces insulin secretion after eating a meal. This is especially true fordiabetics, as well as for people controlling body weight, because the low amount of insulin circulating in the blood promotes the use of fat tissue as a source of energy.

Resistant starch is metabolized only 5-7 hours after eating a meal, unlike glued starch, the digestion process of which begins immediately after eating. As a result, the hypoglycemic effect of resistant starch prolongs and the feeling of fullness lasts longer.

Foods containing RS-3 reduce postprandial glycemia and may be of particular importance in controlling metabolism in type II diabetes. For resistant starch to have a beneficial effect in lowering blood sugar and insulin levels, it must make up at least 14% of the total starch in a meal.

Lowering blood cholesterol

The hypocholesterolemic effect of resistant starch has been extensively documented in animal studies. Short-chain fatty acids resulting from the fermentation of resistant starch affect lipid metabolism.

In the experimental animals fed with fodder with resistant starch, a reduction in the level of total cholesterol, low and very low density lipoproteins (LDL and VLD), ie the fraction of "bad" cholesterol, triglycerides, but also the fraction of "good" HDL cholesterol, was found.

Human studies show a positive or neutral effect on the level of lipoproteins in the blood plasma. When consuming fasting-resistant starch, the study group showed a decrease in total cholesterol and triglycerides or no change.

The mechanism of action of starch resistant to fat metabolism in the human body requires more detailed knowledge, however, it has been suggested that the reduction in blood cholesterol content as a result of resistant starch consumption is associated with a change in the composition of bile acids secreted into the large intestine.

Lower risk of gallstones and gout

A diet rich in easily digestible starch contributes to the formation of gallstones due to increased insulin secretion, while the introduction of resistant starch into the diet reduces the risk of gallstones.

This conclusion was made on the basis of an analysis of the diet of the surveyed populations from highly developed and developing countries.

As a result of the observation of changes in the content of individual indicators in the blood after the introduction of resistant starch to the diet, it was noticed that its increased share in the diet results in a decrease in serum uric acid concentration, and thus reduces the risk of developing gout.

Better absorption of minerals

Resistant starch increasesthe absorption of many minerals at the level of the ileum in rats and humans. Increased absorption of calcium, magnesium, zinc, iron and copper was noted in animals fed a diet rich in resistant starch.

In humans, resistant starch appears to have the greatest effect on calcium absorption. Comparing the absorption of calcium, phosphorus, iron and zinc in a meal containing only digestible starch and a meal with 16.4% resistant starch, the level of mineral absorption was much higher in the second case.

Important

Resistant starch - role in slimming diets

Starch-rich carbohydrate products are most caloric immediately after heat treatment, when the starch is most glued and therefore most easily digestible.

The colder the potatoes or pasta, the more starch is retrograded, the proportion of resistant starch increases and the caloric content of the dish decreases. This phenomenon can be used in weight loss diets and weight control.

To increase the amount of resistant starch in your menu, you can replace warm, carbohydrate-rich dishes with potato or pasta salads, as well as desserts, e.g. with rice.

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