Could you tell me about the importance of fiber? I’ve read stuff about it can supposedly lower your cholesterol and might even preventing cancer. It all sounds like hocus pocus to me. Can you give me the low down?
Dr. Doug’s Answer
The benefits of fiber may sound like a lot of hocus pocus, but it all makes sense physiologically. It really is an amazing and important part of our food.
Simply put, fiber is a part of our food that is resistant to the digestive processes that normally break down our foods. So why is it a good thing to have parts of your food that don’t digest? Fiber goes through the entire system adding bulk to the stool. It binds waste products and toxic byproducts as it travels along and promotes healthy elimination. It is like a big pipe cleaner, scrubbing the digestive tract of impurities and built up junk.
It’s this function of fiber that seems to lead to these “magical” properties. Cholesterol is an important component of bile, the digestive juice that helps to break down fats. It binds to cholesterol and removes it with the other waste leading to lower levels of cholesterol in the blood.
How fiber lowers cancer rates is a little more theoretical. There have been a number of studies that have found an association between high-fiber diets and lowered rates of certain types of cancer, including colon and breast cancer. It is theorized that fiber actually binds carcinogens in the digestive tract which are eliminated as waste instead of remaining in the body and acting on cells. It also decreases the total transit time of food through the body, therefore lowering the amount of time harmful substances are exposed to the body, possibly leading to less incidence of cancer.
But fiber may also affect cancer by its role in digestive tract immunity. The large intestine contains billions beneficial bacteria that are an essential part of a healthy body. Many nutritionists consider the beneficial bacteria of the digestive tract one of the first lines of defense in the immune system as they contribute to the digestive tract’s integrity and prevent toxins from being absorbed. These bacteria use some of the fiber consumed as fuel for their own growth. Byproducts of this, including molecules called short-chain fatty acids (SCFA) are associated with a decrease in cancerous colon cells. They also contribute to maintaining healthy blood sugar levels and healthy intestinal tract cell walls which use the SCFAs for structure and energy.
So fiber not only contributes to bulking up your own digestion, it also feeds the important good guys in your digestive tract. Healthy gut bacteria means a healthy host. You can see that it is quite unique in its role in digestion and how no other element of our food can take on the same role. There’s no magic here, just important food science.
Remember, fiber is only found in plant foods, not animal foods. So load up on those veggies, fruits, beans, legumes, grains, nuts and seeds. Different plant foods have different fiber combinations, all of which are important. So make sure you get a variety of plant foods to maximize the types of fiber you’re getting.