Resistant Starch 101 — Everything You Need to Know

Resistant Starch 101 — Everything You Need to Know
Starches are long chains of glucose that are found in grains, potatoes, and various foods.
7/17/2018
Updated:
7/17/2018

Most of the carbohydrates in your diet are starches.

Starches are long chains of glucose that are found in grains, potatoes and various foods.

But not all of the starch you eat gets digested.

Sometimes a small part of it passes through your digestive tract unchanged.

In other words, it is resistant to digestion.

This type of starch is called resistant starch, which functions kind of like soluble fiber.

Many studies in humans show that resistant starch can have powerful health benefits.

This includes improved insulin sensitivity, lower blood sugar levels, reduced appetite and various benefits for digestion (1).

Depending on how foods are prepared, the amount of resistant starch changes.

It goes through your stomach and small intestine undigested, eventually reaching your colon where it feeds your friendly gut bacteria (4).
The bacteria in your intestine (the gut flora) outnumber the body’s cells 10 to 1 — in that respect, you’re only 10% human (5).
Whereas most foods feed only 10% of your cells, fermentable fibers and resistant starches feed the other 90% (67).
There are hundreds of different species of bacteria in your intestine. In the past few decades, scientists have discovered that the number and type of bacteria can have a profound impact on your health (89).
Resistant starch feeds the friendly bacteria in your intestine, having a positive effect on the type of bacteria as well as their number (1011).

The most important of these short-chain fatty acids is butyrate (15).
Butyrate is the preferred fuel of the cells that line your colon (16).

Therefore, resistant starch both feeds the friendly bacteria and indirectly feeds the cells in your colon by increasing the amount of butyrate.

Resistant starch has several beneficial effects on your colon.

It reduces the pH level, potently reduces inflammation and leads to several beneficial changes that should lower your risk of colorectal cancer, which is the fourth most common cause of cancer death worldwide (1718).
The short-chain fatty acids that aren’t used by the cells in your colon travel to your bloodstream, liver and the rest of your body, where they may have various beneficial effects (1920).
Due to its therapeutic effects on the colon, resistant starch may aid various digestive disorders. This includes inflammatory bowel diseases like ulcerative colitis and Crohn’s disease, constipation, diverticulitis and diarrhea (21).
In animal studies, resistant starch has also been shown to increase the absorption of minerals (2223).
However, the role of butyrate in health and disease needs to be studied properly in people before any strong recommendations can be made.
SUMMARY
By increasing the production of butyrate, resistant starch feeds the cells of your colon and leads to various improvements in the function of your digestive system.

Health Benefits of Resistant Starch

Resistant starch has various benefits for metabolic health.
Several studies show that it can improve insulin sensitivity — the responsiveness of your body’s cells to insulin (24).
Resistant starch is also very effective at lowering blood sugar levels after meals (2526).
What’s more, it has a second meal effect, meaning that if you eat resistant starch with breakfast, it will also lower your blood sugar spike at lunch (27).
The effect on glucose and insulin metabolism is very impressive. Some studies have found a 33–50% improvement in insulin sensitivity after four weeks of consuming 15–30 grams per day (2829).

The importance of insulin sensitivity cannot be stressed enough.

Having low insulin sensitivity (insulin resistance) is believed to be a major risk factor for several serious diseases, including metabolic syndrome, type 2 diabetes, obesity, heart disease and Alzheimer’s.

By improving insulin sensitivity and lowering blood sugar, resistant starch may help you avoid chronic disease and improve your quality of life.

The higher the resistant starches content in a food, the fewer calories it will have.

Several studies show that soluble fiber supplements can contribute to weight loss, primarily by increasing feelings of fullness and reducing appetite (3031).
Resistant starch appears to have has the same effect. Adding resistant starch to meals increases feelings of fullness and makes people eat fewer calories (323334).

Several commonly consumed foods are high in resistant starch.

This includes raw potatoes, cooked and then cooled potatoes, green bananas, various legumes, cashews and raw oats.

As you can see, these are all high-carb foods, making them out of the question if you’re currently on a very low-carb diet.
However, you can eat some if you’re on a low-carb diet with carbs in the 50–150-gram range.

That being said, you can add resistant starch to your diet without adding any digestible carbohydrates. For this purpose, many people have recommended supplements, such as raw potato starch.

Raw potato starch contains about 8 grams of resistant starch per tablespoon and almost no usable carbohydrate.

What’s more, it’s very cheap.

It tastes kind of bland and can be added to your diet in various ways, such as by sprinkling it on your food, mixing it in water or putting it in smoothies.

Four tablespoons of raw potato starch should provide 32 grams of resistant starch. It’s important to start slowly and work your way up, as too much too soon can cause flatulence and discomfort.

There’s no point in taking much more than that since excess amounts seem to pass through your body when you reach 50–60 grams per day.

Kris Gunnars, BSc is a nutrition researcher with a Bachelor’s degree in medicine. This article was originally published on Healthline.

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