Fiber & Why it is Marvelous: Part Two (Soluble)

What can be described as gooey and causes fermentation? That would be soluble fiber. It may not sound appealing, but to our bodies soluble fiber is a true terrestrial gift. Like the saying goes, don’t judge a book by its cover (or in this case, its sludginess).

When comparing the two types, what differentiates soluble from non-soluble, is that soluble fiber turns into a gel when added to water, whereas non-soluble will not. Oatmeal is a prime example. When you place the oats into boiling water, within seconds you’ll have a paste. The longer you cook it, the thicker it becomes.  

If you did this with a bell pepper, you’ll have a soggy pepper, but it won’t be a gel.

Take a bite of that oatmeal and the viscous, glutinous fiber oozes through your digestive track. A similar action happens with the soft insides of apples. Part of what gives the meat of the apple its shape is a substance called pectin. Pectin is actually a type of soluble fiber. After you bite into the apple, chew it up, and send it down the hatch, your body will then take the nutrients it needs and discard the pectin (but not before the pectin works some magic…we’ll get to that…)

Of course pectin isn’t alone. It belongs to a family of soluble fibers that like to hang out in our food, such as inulin oligofructose, mucilage, beat-glucans, psyllium, polydextrose pylols, resistance startch, and wheat dextrin.

Fiber Smart Powder Supplement, made from soluble corn fiber (3g per 1 tsp)

Fiber Smart Powder Supplement, made from soluble corn fiber (3g per 1 tsp)

Don’t get caught up on the names. They are long tongue twisters, but being familiar with them will help you know if the food you purchase has functional fiber added to it. Look at your “high fiber” bread. Odds are inulin or wheat dextrin is a guest star.

Going back to how soluble fiber acts in your gut -- I want you to think of silly putty rolling over a floor covered in dirt. As you roll the putty with the palm of your hand, the gummy putty will start to pick up the little speckles of dirt. When you look back at the floor where the putty passed, it will be a little cleaner. Less dirt!

Why am I drilling this point home? Because it gives insight into why soluble fiber is heart healthy. After you eat, one of the digestive fluids that is called to duty (meaning, to break that burger down) is bile acid. The bile acid will do its job then want to get out of there. If you have sticky soluble fiber in that meal, the broken down bits of bile acid will hitch a ride and go out the shoot at your next bowel movement.

If you do not get enough soluble fiber, the dilapidated bile acid turns into the houseguest that stayed too long. It will set up camp in your intestines or want to be reabsorbed. Here is why this is a problem:

-       Bile acid is high in bad cholesterol, so we don’t want it reabsorbed. Instead, we want “out with the old and in with the new.”

-       If the bile acid is removed, your body will need to make more. Your liver gets the cue to create some, and uses bad cholesterol to do so. Ultimately this lowers the amount of bad cholesterol swimming around your body.

-    The metabolized bits of bile acid can actually damage the walls of your colon, which puts you at greater risk of colon cancer ('nuff said).

 Another benefit of eating the recommended about of soluble fiber is its ability to cause fermentation in your colon. Yes, fermentation, the same process that creates refreshments like beer and wine. This was the magic I was referring to with pectin. Although it may seem odd that this process is beneficial, there is no doubt that fermentation improves the health of your gut, and therefore your overall well being.

 By keeping the good vs. bad bacteria in balance, fermentation allows your colon to better absorb the vitamins and minerals you are eating from food. Basically, it preps the colon for digestion.

Fermentation also helps produce little guys called short-chain fatty acids, which are the main fuel source for your colonic cells (think of it this way, cells have to eat too). Don’t let their pint-sized name fool you, these short-chain fatty acids are powerful protectants of the gut, and some research shows they help reduce the risk of colon cancer as well as boost immunity.

 If you thought fiber was only good for laxation (aka, regular bowel movements), then you were sorely mistaken. Considering your gut health is strongly tied to your immune system, the next time an illness strikes perhaps you should ask yourself, “Have I eaten enough soluble fiber lately?”

 This far into the article, you have a good understanding of why soluble fiber is beneficial, so now let’s go into where we can find it. Listed are 10 foods that contain a substantial about of soluble fiber.

  • 1 ¼ cup fresh Strawberries = 1.1 grams
  • ½ cup cooked Broccoli = 1.2 grams
  • ½ cup cooked peas = 1.3 grams
  • ½ cooked Asparagus = 1.7 grams
  • 1 small fresh Orange = 1.8 grams
  • ½ cup cooked sweet potato flesh = 1.8 grams
  • ½ cup cooked Kidney Beans = 2.0 grams
  • ½ cup cooked Brussels sprouts = 2.0 grams
  • ¾ cup cooked Oat Bran = 2.2 grams
  • ½ cup cooked Black Beans = 2.4 grams

 In Part One of this fiber saga, I stated that our bodies would benefit from 25-38 grams of total fiber each day. How much of that should come from soluble fiber exactly? Well, the Institute of Medicine did not specify this for us, but there is a diet called the Therapeutic Lifestyle Changes diet (TLC for short), that suggests at least 5 to 10 grams of soluble fiber per day, but really pushes for closer to 10 to 25 grams daily.

The TLC is not a fad diet, but rather a style of nutritious eating endorsed by the government to help reduce a human body’s serum LDL cholesterol level (the bad kind of cholesterol that can cause major health problems when it gets too high). When the creators of this diet were studying how much soluble fiber to recommend, they found that if you consistently ate 5-10 grams soluble fiber for 6 weeks, you’ll drop your LDL cholesterol by 3 to 5%. Not too shabby.

 Moral of the soluble fiber story: beans, beans they’re good for your heart! The more you eat, the more….prepared your body will be to fight off illness and keep running smoothly! 


3/4 cup cooked oatmeal with heart healthy walnuts

3/4 cup cooked oatmeal with heart healthy walnuts

*All soluble fiber in food values taken from the Harvard University Health Services May 2004, “Fiber Content of Foods in Common Portions” list.