Resistant Starch

In the world of carbohydrates, not all are created equal.

One type of carbohydrate that offers health benefits and digestive support is resistant starch.

This article reviews resistant starch to help you find out if it’s something you should be eating more.


What is a Starch?

Starches are carbohydrate molecules comprised of linked sugar molecules.

Some starches are simple and therefore, digest quickly. Examples of simple starches include white bread, white pasta, pastries, cookies, etc

Other starches are more complex and therefore require more time and effort by the body to digest.  Examples of complex starches include potatoes, winter squash, fruits, quinoa, and whole-wheat products. Complex starches tend to be healthier to consume.

Summary:  Starch is an important part of good nutrition and can either promote or diminish health. Choosing complex starches can help improve health.


What is Resistant Starch?

Resistant starch acts similarly to dietary fiber in that is does not fully digest.

Resistant starch is a portion of starch that does not digest in the small intestine like most other foods. Instead, it makes its way to the large intestine. Here, bacteria ferment it to help make more healthy bacteria for the body.

Due to this effect, researchers often consider resistant starch a prebiotic. In the colon, resistant starch produce short chain fatty acids and create a lower pH environment.

What Makes a Starch Resistant?

The main reason resistant starches avoid digestion until they reach the large intestine is due to their structure.

All starches, resistant or not, are made up of amylose and amylopectin. However, resistant starch has more amylose, which does not break down easily.  Additionally, there are different types of resistant starches that resist digestion based on specific characteristics.

Summary: Due to specific properties, resistant starch evades digestion until fermentation occurs in the large intestine.


Types of Resistant Starches

Currently, four types of resistant starches exist including:

  • Type 1 – Starches such as whole grains, seeds, or durum wheat have a strong cell walls and protein matrices. This helps resist digestion, and slow blood sugar response.
  • Type 2– This type of starch is difficult to break down due to the arrangement of the amylose molecule. Find it in green bananas, uncooked potatoes, gingko, or maize.
  • Type 3 – The cooking and cooling process of certain starches causes retrogradation, which results in resistant starch formation. Eat more cooked and cooled potatoes, whole grain breads, and pasta.
  • Type 4 – This type is a man-made, chemically-modified starch that resists digestion. Find it in many food products like high fiber foods and fibrous food ingredients (1, 2).

Summary: Resistant starch resists digestion through various mechanisms derived from food.  Each type of resistant starch can be found in a wide variety of foods to incorporate in a diet.


Health Benefits 

Incorporating resistant starch into a daily diet can promote numerous health benefits.

  • Promotes gut health – When digested, resistant starch is fermented into short chain fatty acids such as butyrate and other byproducts that assist in gut microbiota growth and diversity (3).
  • May help prevent colon cancer – Although much more human research is needed in the area, a 2016 review of mice with colon cancer treated with resistant starch demonstrated decreased cell proliferation and colon carcinogenesis.
  • Regulates blood sugar – In those with diabetes, consuming resistant starch in place of refined starches lowers post-meal blood glucose and the associated insulin response. Also, resistant starch may decrease blood glucose response during a later meal (4).
  • Assists in weight management – Animal studies have shown that consuming resistant starch helps limit energy intake, reduces fat tissue, increase satiety, and may increase energy expenditure. These mechanisms all assist in weight management and reduction. More human studies are needed in this area (4).
  • Potential prevention of breast cancer – A 2015 study conducted demonstrated resistant starches, specifically whole wheat bread, legumes, and boiled potatoes, may reduce the risk of breast cancer risk. However, more studies are needed to confirm this finding (5).

Summary: Resistant starches can offer a host of health benefits including improving gut health, preventing various types of cancer, regulating blood sugar, and assisting in weight loss.


How to Add More

By eating a plant-based diet, you’ll naturally incorporate more resistant starches.

Here are some tips on eating more resistant starch:

  1. Consume greener, less ripe bananas when you’re picking them out at the store 
  2. For a side dish, include cooked yams, lentils, and chickpeas (6)
  3. Include at least 1 serving per day whole grains such as muesli, oats, buckwheat, barley, brown rice, and whole-wheat products 
  4. Make a smoothie and add in prepackaged resistant starch, such as Bob’s Red Mill Unmodified Potato Starch
  5. Cook starches such as whole-wheat pasta, boiled potatoes, and rice and then allow them to cool prior to eating

Here’s a List of Resistant Starch Foods-

Foods Grams of RS per 100g of food
Muesli 3.3
Buckwheat 1.8
Barley 2.4
Bananas 4.0
Plaintains (cooked) 3.5
Oats, rolled, uncooked 11.3
Lentils 3.4
White Beans 4.2

A full table of foods and the amount of resistant starch they contain can be found here.

Summary: Altering cooking methods, consuming more vegetables and beans, or drinking a quick supplement are easy ways to increase the amount of resistant starch in your diet.


How Much Should I Have?

In the world of nutrition, everyone is unique and requires different amounts of nutrients to function optimally.

However, increasing resistant starch intake can help boost almost anyone’s health. Although healthy for virtually all populations, it is important to receive most resistant starch from whole food sources and not supplements, as pairing it with other fermentable carbohydrates allows the body to utilize it best.

A 2008 survey found that the average American consumes about 5g of resistant starch per day. It was reported that 6-12 g at one meal are needed to assisted blood glucose regulation and about 20g per day is needed to observe health benefits.

Use the list provided above to gauge how much resistant starch you are eating. When increasing resistant starch, do so incrementally as too much too quickly can result in gas and bloating.

Summary: A daily dose of 20g of resistant starch can offer many health benefits. Introduce it slowly to assess tolerance.


Conclusion

Resistant starch can be beneficial to include due to potential benefits in the areas of gut health, cancer prevention, diabetes and blood sugar regulation, and weight management.

Add a variety of carbohydrates to your diet like legumes, greener bananas, muesli, and oats to get more resistant starch into your day. 

Resistant starch is a hot topic with many promising health benefits.

BY ELISE DEMING, RDN, LDN @EAT.WITH.ELISE

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