The Basics of Fiber

I'm sure you've heard by now that fiber is an important part of a balanced diet. But did you know that fiber is technically not a nutrient?

This is because fiber is not digested, nor absorbed by our bodies.

Although fiber is a "non-nutrient", it is still considered a very important contributor to good health.

So what is this non-nutrient?

Basically, it can come in different forms, from plant cell walls or from starches that escape digestion.

For example, uncooked plants like raw banana or many legumes.

What are the different types of dietary fiber?

Soluble Fiber - This fiber specifically works to absorb water in your gut to slow digestion and reduce blood sugar. I like to think about oatmeal and how it absorbs the water.

Insoluble Fiber - This fiber works to bulk up food and relieve constipation by speeding up the digestion process.

Some of the main benefits fiber provides:

1. It adds bulk to our meals

-Because fiber isn't digested and absorbed, it doesn't contribute to our caloric intake. However, our brains are only getting the message of the volume of our stomach, causing us to think we've had enough to eat and thus decreasing the amount of calories we actually consume.

2. It holds water well

-Soluble fiber has the ability to absorb water, which works to increase the gastric distension and thus slowing the rate that stomach contents exit and are digested and absorbed. This is helpful in controlling blood sugar levels and maintaining satiety.

3. It binds bile acid

-Bile acid is used to digest fats in the stomach. Fiber helps to bind bile acid thus disrupting fat digestion, causing some fat to be excreted out of the body instead. This is specifically protective against heart disease.

4. It is fermentible

-Because fiber cannot be digested, it must be broken down by the helpful bacteria that resides in your large intestine. Although this does cause unpleasant gas, it is helpful to keep your colon healthy and prevent colon cancer.

5. It decreases the time food spends in your large intestine

-By reducing the amount of time food spends being digested, you are reducing your chances of experiencing constipation, as well as reducing the chances of having harmful toxins and carcinogens being exposed to your body.

-Remember, anything entering your large intestine is what your body has tagged for excretion, so getting it out of this stage as quickly as possible is wise. So get your fiber in to help clean your body out!

Are you getting enough fiber in your diet?

The Recommended Dietary Allowance for fiber is set at 25-35 grams/day.

Some of the highest levels of fiber are seen in:

Ranked highest to lowest

(Grams per serving)

• Navy beans 19 g

• Black beans 15 g

• Pistachios - 13 g

• Chick peas -12 g

• Kidney beans - 11 g

• Almonds - 11 g

• Chia seeds - 11 g

• Avocado - 10 g

• Raspberries - 8 g

• Lentils - 8 g

• Steel cut/rolled oats - 5 g

• Bran flakes - 5 g

• Quick oats - 4 g

• Broccoli - 3.8 g

• Carrots -3.6 g

• Popcorn - 3.6 g

• Banana - 3.1 g

• Whole grain bread - 3 g

Don't be discouraged.

Just because your diet may not include much of this list, doesn't mean your not getting fiber! This is just a quick list of foods that contain high levels of fiber.

Any plant whole foods such as fruits, vegetables, and grains will contain some amount of cellulose, which is another type of fiber.

---

References

Ross, A. C. (2014). Modern nutrition in health and disease. Philadelphia: Wolters Kluwer Health/Lippincott Williams & Wilkins.