Not All Dietary Fiber is Created Equal


Katie Harris, Product Development & Nutrition Scientist

When people hear the words “dietary fiber”, they almost instinctively associate it with easier bathroom habits (rightfully so!).  The truth is, it’s so much more than that; and that’s why it’s one of the most amazing nutrients that we can consume.  You see, there are many different types of dietary fiber that all perform different functions once they get into our body.  But, let’s take a step back and think about what it means for a carbohydrate source to be considered “dietary fiber”.

Dietary fibers are carbohydrate sources that do not get broken down during typical digestion because they have a specific physical structure that our innate enzymes cannot break down.  There’s two different types of dietary fibers as defined by their chemical properties.  They are classified as either soluble or insoluble fiber; soluble meaning it dissolves in water and insoluble meaning it doesn’t dissolve in water.  This characterization is important because the ability of the fiber to dissolve in water can contribute to its functionality in the body.

The benefit of consuming a variety of fibers is limitless.  As you can see in the above diagram, there are two different types of fibers, both of which have the ability to perform at least one of the three main functions fiber has in our body.  Consuming a variety of fibers is associated with lowering the risk of non-communicable diseases that are plaguing industrialized nations like Cardiovascular Disease and Type 2 Diabetes.  Research is also beginning to show the profound influence dietary fiber has on maintaining and improving our gut health.

One versatile fiber that is extremely important for all of these ailments is resistant starch.  While common starches (like corn starch) are highly digestible by our innate enzymes, resistant starch has a specific physical structure that is different from a regular starch, and thus it’s un-digestible and delivers a unique functionality compared to other dietary fiber sources.  Because resistant starch doesn’t get broken down by our digestive enzymes, it doesn’t contribute to our blood glucose like regular digestible carbohydrates do.  Consuming too many digestible carbohydrates over time can lead to blood sugar abnormalities like insulin resistance, and the subsequent development of Type 2 Diabetes.

One of the more unique functionalities resistant starch has in our body is its ability to get slowly fermented throughout our gut, which not only ensures we are having a comfortable digestion process, but the bi-products of the fermentation response have a number of health benefits.  The millions of bacteria that live in our gut love to metabolize (or ferment) whatever food substrates did not get digested and absorbed in the preceding small intestine.  Because resistant starch doesn’t get digested in the small intestine and because its physical structure is unique to that of other fibers, the bacteria respond a little differently than they would with other fermentable fiber sources.

The bacteria slowly ferment the resistant starch and as a result release short chain fatty acids like butyrate, propionate, and acetate. These short chain fatty acids then act at a number of different locations all throughout the body. Butyrate is used as the primary energy source for our colon cells, which is a highly beneficial response that can help control proper cellular growth and as a result may prevent colon cancer from developing.   Propionate and acetate tend to leave the digestive tract and travel to other areas of the body where they can participate in mechanisms like regulating our glucose utilization and forming healthy cholesterol.  The production of these short chain fatty acids also has more of a local effect that has downstream benefits for the gut as a whole.  The short chain fatty acids will lower the pH of the colon, which allows for proper nutrient absorption and ensures that there is a healthy balance of good bacteria and bad bacteria in our gut.

Interestingly enough, you can find resistant starch in so many of your favorite foods.  Some examples include green bananas, oats, legumes, and wheat-based products made with HealthSense™ High Fiber Wheat Flour.  HealthSense is a unique variety of wheat that inherently contains 10-20x the amount of fiber in traditional wheat in the form of resistant starch.  It allows you to consume your favorite wheat-based foods that everyone seemingly tells you to avoid (like white bread, tortillas, and pasta) without any guilt!  Not only will your gut get a heaping, delicious dose of resistant starch (your body will thank you), but you don’t have to worry about rapidly spiking your blood glucose. One of my favorite tricks for getting more fiber and resistant starch in my diet is making this easy and delicious breakfast quesadilla:

Breakfast Quesadilla

1 tortilla made with HealthSense™ Flour
1 tbsp. nut butter
1 green banana
2 tbsp. rolled oats
½ tbsp. chia seeds

  1.  Spread nut butter along half of the tortilla
  2. Cut green banana into slices and spread along the nut butter.  Sprinkle with oats and chia.
  3. Fold the tortilla in half and enjoy!
This Breakfast Quesadilla made on a HealthSense tortilla includes nut butter, banana, oats and chia seeds.

This Breakfast Quesadilla made on a HealthSense tortilla includes nut butter, banana, oats and chia seeds.