Wellness Friday with MAKwellness

Carbohydrates 101:  Fiber as a Super Food, Part Five

By:  Maria Kasdagly
In MAKwellness

Fiber has become an everyday term used when talking about anything nutrition.  Even though it is not considered a nutrient, food labels now show fiber content and many health professionals claim that Americans don’t consume enough fiber on a daily basis.  The goal of this section is to discuss the physiological effects of fiber and how those effects help your colon health while also aiding in one epic bathroom session sure to make any speedo or two-piece feel amazing on.

What is Fiber?

Plant cell walls contain more than 95% of dietary fibers.  Dietary fiber is found only in plant foods (i.e. fruits, vegetables, grains, and legumes).  There are two types of dietary fiber–soluble and insoluble fiber.

Soluble fiber dissolves in hot water and insoluble fiber does not dissolve in water.  Soluble fiber are gums, pectins, some hemicelluloses, and beta-glucans and can be found in foods such as berries, any beans, any peas, flax seeds, plums, apples, and oats.  Fiber from psyllium seed, an ingredient in some over-the-counter laxatives, is also in this group.

On the other hand, insoluble fibers, which provide structure to plants are primarily lignins, cellulose, and some hemicelluloses.  Insoluble fiber can be found in vegetables, brans, nuts, seeds, and the skins of fruits and vegetables.   Most foods contain mixtures of both types of fibers, but generally vegetables and wheat, along with most grain products, contain more insoluble fibers than soluble fibers.  Both soluble and insoluble fibers are important to your health for different reasons, which are discussed below.

Health Benefits of Fiber:

The physiological and metabolic effects of fiber vary based on the type of ingested fiber but in general fiber is vital for good health.  Although fiber is not digested, it is bulky and therefore increases satiety.  Soluble fiber is viscous, meaning it is able to pull water from the body.  Think of soluble fiber as a dry sponge, so as it moves throughout the digestive tract it soaks up water and digestive juices.  Soluble fiber will also delay the stomach from emptying into the intestines, which is partly why soluble fiber tends to decrease theglycemic effect of the meal.    Fiber is also sticky, so on it way through the digestive tract it helps to pick up harmful chemicals, potentially carcinogenic chemicals, that find their way into the intestines.   Mechanisms in which dietary fibers prevent disease are multiple and varied, but the outcomes can include avoidance of constipation-based diseases such as colon cancer, diverticulitis, hemorrhoids, and varicose veins.

Fiber’s Preventative Role Against Colon Cancer

Often we think of our colon as the place where we hold our human “waste” until that waste makes it grand adventure down the toilet.  But there is so much more to our colon than just are “poop holding tank”.  As previously discussed, 70% of our immune cells reside in the lining of our intestinal walls, thus it’s important to eat a diet that will nurture and  support the health of our colon.

Many fibers once they reach the colon are fermented by the good bacteria, and can produce favorable effects for the body.  Fermentable fibers, predominantly from soluble fibers, stimulate the production of bacteria and can also generate short-chain fatty acids for use by the body.  Short-chain fatty acids are hard to get in the diet, so our body depends on our mighty colon to make these fats.  Research is showing that these fats help keep the colon cells healthy and thus prevent diseases, such as colon cancer.  Also, fiber fermentation creates an acidic environment in the colon, which decreases the synthesis of secondary bile acids.  Decreasing secondary bile acids has been shown to decrease the generation of tumors.  Unlike soluble fiber, insoluble fibers resist fermentation (degradation).  This allows insoluble fibers to bind carcinogens, which thereby minimizes the chances of the carcinogen interacting with the colon cells.

Other Benefits of Fiber:

Besides increasing satiety and contributing to overall colon health, fiber may benefit us in other ways.  It has been shown to decrease triglyceride and bad cholesterol levels, increase frequency and volume of defecation (making you feel like a super star), and may even help prevent diabetes, heart disease, ulcers, and other types of cancer.


  1. Gropper, SS, Smith, JL, Groff, JL (2008) Advanced Nutrition and Human Metabolism. Belmont, California: Wadsworth.
  2. Campebell, CT and Campbell, TM (2006) The China Study:  Startling Implication for Diet, Weight Loss and Long-Term Health. Dallas, Texas: BenBella Books, Inc.


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