Dietary Fiber is Essential for a Healthy Diet

You have probably been told at some point that you should eat more fiber.  Most people know fiber for its ability to prevent or relieve constipation, but it doesn't just keep your bowel habits regular!  Foods containing fiber can provide several health benefits, from maintaining a healthy weight to lowering your risk of some cancers.  

What is dietary fiber?

Dietary fiber includes the parts of plant foods that your body can't digest or absorb.  Other food components, such as fats, carbohydrates, and proteins, are broken down and absorbed by your body.  But fiber is not digested by your body; human cells just don't have the enzymes to digest fiber.  Instead, it passes through the stomach and small intestine relatively intact.  However, it can be digested to some degree by the good bacteria that live in your gut, primarily in the large intestine.  These bacteria are commonly referred to as your microbiome.  

What are the different types of fiber?

• Soluble fiber - This type of fiber will dissolve in water to form a kind of gel.  This type can help to lower blood cholesterol and glucose levels.  It is found in oats, apples, citrus fruits, carrots, peas, beans, and psyllium.
• Insoluble fiber - As the name implies, this type of fiber does not dissolve in water.  It promotes the movement of material through your digestive system and increases stool bulk.  It can be very beneficial in preventing constipation or irregular stools.  It can also help with people who suffer from diarrhea, by adding bulk to the stool.

Let's talk more about your microbiome, the good or friendly bacteria that live in your gut.

Your body works as well as it does in large part due to a mutually beneficial relationship between you and what we think of as "good" bacteria.  Good bacteria live on the skin, in the mouth, in the nose, and in your gut.  The great majority of those are living in the gut, primarily in the large intestine.  

Up to a thousand different species of bacteria live in the intestine.  They are also known as the gut flora, or the gut microbiome.  They can do things that your body cannot do on its own.  Some of these bacteria are crucial for many aspects of your health, including weight control, blood sugar control, immune function, and even brain function.

Here's where fiber comes in.  Your body is breaking down and absorbing all the fats, carbohydrates, and proteins before they get to the large intestine.  This leaves none of those for the bacteria to eat.  Since you can't digest fiber, it reaches the large intestine essentially intact.  Intestinal bacteria do have the enzymes to digest many of these fibers.  

Dietary fiber is feeding these good bacteria.  In return for you providing this food for the bacteria, they produce certain nutrients for your body.  These nutrients can decrease inflammation in your colon and provide benefits throughout your body.

What are the health benefits of a high-fiber diet?

• Normalizes bowel movements - Fiber increases the weight and size of the stool and softens it.  This decreases the risk of constipation.  If you have loose or watery stools, fiber can help to solidify the stool, because it absorbs water and adds bulk to the stool.
• Lower cholesterol levels - Soluble fiber can lower cholesterol levels, particularly "bad" cholesterol levels.  
• Helps control and prevent diabetes - Fiber, particularly soluble fiber, can slow the absorption of sugar, making blood sugar levels more steady, with fewer highs and lows.  This is particularly important for people who already have diabetes.  Studies also indicate that a healthy diet that includes insoluble fiber may reduce the risk of developing type 2 diabetes.
• Lowers inflammation levels - The nutrients produced by the gut bacteria can lower the level of inflammation in the intestine and throughout your body as well.  This includes inflammation in blood vessels, which helps lower your risk of heart attack and stroke.
• Healthy weight - High-fiber foods are more filling than low-fiber foods.  They are less dense in energy, meaning that they have fewer calories for the same volume of food.  They also keep your appetite satisfied longer, so you don't get hungry as quickly.
• Maintain overall bowel health - Higher fiber intake lowers your risk of developing hemorrhoids as well as the small pouches in your colon called diverticuli.  Diverticular disease can lead to recurrent infections of the colon and can even rupture like your appendix.
• Lower risk of colon cancer - Studies have found that a high-fiber diet lowers the risk of colorectal cancer.
• Longer life - Studies suggest that increasing your fiber intake is associated with a reduced risk of dying from cardiovascular disease and all cancers.

Next week, one of our dieticians will be giving you more information about how much fiber you need and some tips for adding fiber to your diet.

If you have any questions about dietary fiber, please log into your account and send us your question. We are here to help.

Dr. Anita Bennett MD - Health Tip Content Editor