Facts about Fiber

by Dr. Tracy Gilbert, ND
Naturopathic Doctor

If you are like most Canadians, you are probably not getting adequate amounts of fiber in your diet.  According to the Heart and Stroke Foundation, the average Canadian consumes only 14 grams of fiber daily – this is significantly below the recommended amount of 26 to 38 grams.

Before discussing ways to increase fiber in the diet, let’s review some of the important facts.  Fiber is a carbohydrate found in the indigestible cell walls of plant foods.  It is essentially what remains after your body has removed all of the nutrients from fruits, vegetables, and grains.  Although the fiber itself contains no vitamins or minerals and is not digested by the body, it does play an essential role in supporting overall health.  For example, research has shown that fiber has the following benefits:

  • Improves digestion – Most people are aware that fiber regulates bowel movements.  It helps to prevent constipation, diarrhea, ulcers, hemorrhoids, and digestive diseases by improving the bulk and passage of the stool.  A lesser known fact is that fiber also serves as a food source for the body’s healthy intestinal bacteria (also referred to as flora).  These bacteria play an important role in maintaining a healthy immune system by producing antifungal, antibiotic, and anti-carcinogenic substances.
  • Improves the elimination of toxins from the body – The digestive system produces toxins as food breaks down and decays.  If decaying food sits in the intestinal tract for too long, the toxins get reabsorbed back into the blood stream and the intestines become a perfect breeding ground for yeast (candida), unhealthy bacteria, and parasites.  Fiber helps to prevent these problems.  As it travels through the intestinal tract, it sweeps and binds to toxic substances to remove them from the body with the stool.
  • Reduces risk of certain types of cancer – Fiber binds to potential cancer-causing substances in the intestines and reduces risk of colon cancer.  In addition, fiber may reduce the risk of breast cancer in women.  One study revealed that pre-menopausal women who ate 30 grams of fiber daily had half the risk of developing breast cancer compared to those who ate less than 20 grams.
  • Lowers cholesterol levels – Fiber, particularly soluble fiber as found in oats, helps to reduce blood cholesterol levels by binding to bile salts in the intestines and removing them from the body with the bowel movement.  Bile salts contain fats and cholesterol – if they are not properly excreted in the stools, they will be reabsorbed into the blood stream and contribute to elevated cholesterol levels.
  • Promotes weight loss – There are many reasons why fiber can help you to lose weight. Firstly, high fiber foods require more time to chew.  This gives the body the opportunity to signal when you are full which may prevent overeating.  Secondly, high fiber foods fill you up and keep you feeling satisfied for longer periods of time.  Thirdly, fiber reduces insulin secretion and this can help to prevent food from being stored as fat.

Now that you know why you should get plenty of fiber in your diet, let’s turn our attention to how you get it.  Fiber is found only in plant foods – in other words, foods that grow from the ground.   You will find fiber in fruits, vegetables, whole grains, beans, lentils, nuts and seeds.  In contrast, fiber is not found in meat, dairy products (e.g., milk, cheese and eggs), or processed grains (e.g., white flour) – the staples of the North American diet.  A diet high in these fiber-depleted foods is linked to all of the diseases associated with industrialized societies including cancer, high blood pressure, high cholesterol, heart disease, diabetes, and obesity.

Let’s take a look at some examples of food sources of fiber:

  • Sources of Fiber (i.e., foods that contain more than 2 grams of fiber per 1/4 cup) – bananas, apples, brown rice, corn, oranges, shredded wheat, green peas, sweet potato, carrots, peaches, pears, strawberries, and spinach.
  • High Sources of Fiber (i.e., foods that contain more than 4 grams of fiber per 1/4 cup) – split peas, baked potatoes with the skin, figs, raisins, dried apricots, corn bran cereal, broccoli, bran flakes, and dates.
  • Very High Sources of Fiber (i.e., foods that contain more than 6 grams of fiber per 1/4 cup) – 100% bran cereal, red lentils, white beans, and kidney beans.

Tips for increasing fiber:

  • Replace white bread with multi-grain bread.  Note: whole wheat bread is often white bread dyed brown!
  • Include more whole grains with breakfast (e.g., whole rolled oats, oat bran, whole-grain granola or muslei).
  • Pre-wash and cut fresh vegetables to have as a convenient mid-day snack.
  • Try hummus as a dip for raw vegetables – it is made from chic peas and is high in Fiber.
  • Replace white rice with brown rice.
  • Eat fresh fruit instead of fruit juices.
  • Introduce fiber slowly.  A sudden increase in fiber can lead to temporary gas, bloating, and/or cramping.
  • Drink plenty of water.  If you increase fiber without increasing water, it can contribute to constipation.  Be sure to drink at least 8 glasses of water daily.  Note:  Sorry to break the news, but other fluids (such as coffee, tea and juice) are not a replacement for water.
  • Consider a fiber supplement (e.g., psyllium, powdered greens, or ground flaxseeds).  Note: Fiber supplements should be taken away from medications and other supplements.  Remember that fiber binds to substances in the intestines and eliminates them from the body.  Taking your medication at the same time as a fiber supplement may reduce its absorption and effectiveness.