Okay, I’m a little ashamed to admit this, but I’m going to keep it real.

I haven’t heard of resistant starch until recently. Either my professors failed to mention about it throughout my four seemingly endless years of bachelor, or I was clearly not a very good student.

Nevertheless, I am glad that I was able to catch wind of this topic. Better late than never, right?

So, what the heck is resistant starch?

Overview of Resistant Starch

Mounting of research supports the benefits of fiber for diabetes, weight loss, heart disease, and gut health. While we are much familiar with the terms soluble and insoluble fibers, resistant starch (RS) is the little black sheep that many believe will slowly but surely make a name for itself soon.

Resistant starch is divided into five categories based on their enzyme resistance. Like the name suggests, RS is a type of starch that “resist” digestion and is not absorbed by the body.

RSI: Physically inaccessible to digestive enzymes. Found in whole or partially milled grains, seeds, and legumes.

RSII: Structure of the starch makes it difficult for enzymes to digest it. However, cooking allows the breakdown of the structure and access to digestive enzymes. Found in raw potato, underripe banana, and some legumes.

RSIII: Known as retrograded starch. Cooked then chilled foods like pasta, rice, and potatoes have a higher RS content then their freshly-cooked-hot version.

RSIV: Chemically modified starch

RSV: Amylose-lipid complex

Green banana tops the list of highest RS content among unprocessed foods.

Americans consumed roughly 3-8 grams of RS every day.

Health Benefits

Resistant starch is not digested in the small intestine. Instead, it makes its way to the colon where it is fermented by microbiota. Fermentation of these prebiotic fibers gives birth to compounds called short-chain fatty acids (SCFA) as a result of bacterial fermentation. Short-chain fatty acids have been suggested to play a hand in reducing the risk of colorectal cancer. Others benefits of RS that have been postulated include relief of constipation by increasing fecal bulk and of irritable bowel syndrome (IBS) by reinforcing the gut barrier through mucin production.

Resistant starch is a prebiotic fiber that feeds the bacteria of the gut. Because of the slower rate of fermentation, less gas is produced, and people can tolerate a higher amount of it.

Glycemia

Considering the several similarities RS share with both soluble and insoluble fibers, researchers sink their minds into the possible effect of RS on glycemia and insulin. Unfortunately, the results from studies continue to yield mixed results. Their methodology could explain such difference in their findings. Looking at the studies as a whole, it does seem like RS reduces postprandial blood sugar.

Weight loss

Since RS is a type of fiber, it is reasonable to be under the impression that it holds the same satiety effect as fiber. However, the handful of human studies evaluating this property leaves researchers skeptical about this matter. Therefore, the extent of RS in weight loss is still up for debate.

The Magic of Cooking

While potato in its raw state is packed with RS, cooking greatly reduces its content. However, chilled potato, as discussed in a previous post, increased the formation of RS type 3, given that certain criteria are met.

The food structure of potatoes makes it hard for the gut enzymes to digest it. This problem is easily solved once they are cooked in water: the change within the food matrix allows the enzymes to break down the starch easily and the body to absorb it. Cooling them modifies the structure again, yielding more RS and making it challenging for digestive enzymes to do their work.

Boost Your RS Intake

Here are some neat tricks to raise the amount of RS in foods:

• Eat chilled or reheated pasta instead of freshly cooked pasta
• Eat chilled or reheated potatoes instead of boiled hot potatoes
• Eat underripe bananas instead of overripe ones
• Eat frozen-reheated bread instead of fresh bread

Some dietitians encourage people to consume products that contain Hi-maize resistant starch or to straight-up purchase the ingredient itself. Consumers partially replace flour in their recipes with Hi-maize resistant starch. Some even sprinkled on their oatmeal to increase their RS intake.

Bottom Line

No doubt that future research will strengthen the evidence we currently have for RS. In the meantime, you can give Hi-Maize Resistant Starch a try and apply the simple tips discussed above to boost your intake of RS.

References:

A Evans. Resistant Starch and Health. In: Wrigley C., Corke H., Seetharaman K., Faubion F. eds. Encyclopedia of Food Grains. Waltham MA: Elsevier; 2016: 230-235.

Carbs and Cooking. Diabetes UK. URL Link. Accessed September 30, 2016.

Jill W. Resistant Starch – This Type of Fiber Can Improve Weight Control and Insulin Sensitivity. Today’s Dietitian. URL Link. Published 2012. Accessed September 30, 2016.