ancestors probably consumed more fiber than you do! Before the days of advanced milling technology, gristmills ground wheat, corn, and other grains into meal or flour. Using the power of a moving river, grain was milled between two coarse stones. Then it was sifted to remove the inedible chaff, or husk, leaving all the edible parts of the grain.
The bran and the germ that contain fiber and many essential nutrients remained. Whole grains were the only grains people knew. In some parts of the world, that’s still true today; in fact, some people still pound their grain by hand to make flour.
As technology improved, the bran and the germ were separated and removed, leaving refined white flour. With this new process came new status. White bread with its softer texture and high-class appeal became more desirable than coarser, darker bread.
But it was more expensive and only available to those who could afford it. For the same reasons, white rice became more desirable than brown rice. Simply put, refined was “in”! With this switch to refined grains, however, people became short-changed on many nutrients—including fiber—without knowing it.
In the 1940s, recognizing the health consequences, manufacturers began enriching many grain products. Now, some nutrients lost during processing—thiamin, riboflavin, niacin, and iron—are added back. In some, fiber is added back, too. Since the late 1990s, enriched grain products have also been fortified with folic acid.
Fiber: It’s Very Important!
We talk about fiber as a single component of food, but it’s not that simple. Actually, dietary fiber is a general term, referring to certain complex carbohydrates and lignin that your body cannot digest or absorb into your bloodstream. Instead of being used for energy like other carbohydrates, fiber is eliminated. Fiber is considered to be a phytonutrient, a component of food that promotes your good health in many other ways.
Fiber: Just What Is It?
Plants—and foods of plant origin—count on fiber for their shape. It’s fiber that gives celery its rigid stalk and gives spinach the strong stems that hold up its leaves. That same structure “bulks up” the contents inside your digestive tract. Like starch, most fibers are made of many sugar units, so they’re actually polysaccharides.
In dairy cows, bacteria in digestive juices break down fiber in their grassy meals, providing energy to produce milk. However, human digestive enzymes cannot break fiber into units that are small enough for absorption. That’s why fiber isn’t converted to energy, or calories, in your body. That very quality gives fiber its own unique roles in health.
(Technically, your body can digest very small amounts of some fibers. But the amount is much too small to count.) Not well studied, some nondigestible carbohydrates also come from animal-based foods. This type of fiber may have benefits to human health, too.
Soluble and insoluble: different types of fiber with different missions! What makes them unique? Soluble fiber dissolves in water, and insoluble fiber doesn’t.
These differing qualities allow them to keep you healthy in different ways although some major health benefits are attributed to both. With the mixture of foods people eat, about two-thirds to three-quarters of their fiber intake is likely soluble.