The fiber revolution began with British surgeon Denis Burkitt. In 1970, Burkitt published the best-selling, "Don't Forget the Fiber in Your Diet," in which he presented to the public what he had observed about fiber and digestive health after years of comparing the diets of British soldiers stationed in Uganda with the Ugandan natives.
Burkitt concluded many Western diseases that were rare in Africa were the result of diet and lifestyle. Fiber suddenly was a hot topic and became the subject of ongoing research that ultimately characterized different fibers and their effects. Benefits were seen on not only digestive health, but on conditions beyond those narrow parameters.
Soon after, it became popular to pump up breakfast cereals with bran and re-create whole grain breads. But a specific type of fiber became the most demanded: soluble fiber. This complex carbohydrate gave dietary fiber a new image and expanded purpose. While the bran in cereals could relieve constipation because of its insoluble wood chip-like nature, soluble fibers seemed to have the power to lower cholesterol and slow the entrance of sugar into the blood.
Soluble fibers bind water, and this water-binding ability gives them a gel-like consistency that slows the movement through the small intestines resulting in delayed sugar absorption.
The same water-binding capacity also allows soluble fibers to trap the bile secreted by the gallbladder into the small intestine in response to dietary fat. Here the bile acts as an emulsifier allowing fat-digesting enzymes to do their job. Since bile is made of cholesterol, the removal of fiber-bound bile from the body forces the liver to pull cholesterol out of the blood, make more bile, and store it in the gallbladder.
Today, the growing list of soluble fibers wears a new badge: prebiotics. They include ingredients such as beta-glucans and resistant starch, because they are the preferred food of probiotic gut bacteria. The fibers that these healthful gut bacteria use for energy occur naturally in a variety of fruits, vegetables, legumes and grains.
Hundreds of studies have shown that the bacteria in the gut play an important role in maintaining digestive health due to their interaction with the immune system. Alterations in the gut microbiome are associated with a host of inflammatory disorders, such as Chron's Disease, Irritable Bowel Syndrome and colitis.
With rapidly occurring advances in genetic research, scientists are now able to create detailed maps of the genomic sequences of the microbes found within the gut. The ultimate aim is to develop a greater understanding of healthy gut maintenance.
Because of these advances, scientists can monitor the range of microbes within individuals and populations allowing them to pinpoint specific species that may promote or interfere with digestive health. This type of research is opening entirely new ways to treat digestive disorders, especially through prescribing specific strains of bacteria.
Eating to feed healthy gut bacteria in a general sense has been going on for quite some time. That's why yogurt and similar cultured foods have always been popular in other countries and is catching up in popularity in the U.S. over the past couple of decades. However, targeting specific portions of the gut microbiota to treat disease is a daunting task.
While proving clear cause-and-effect relationships between gut microbiota and health are difficult, definite patterns have emerged. For example, researchers have demonstrated that elderly persons residing in long-term care facilities display a decrease in the compositional variation of intestinal microbiota compared to their community-dwelling counterparts. But most importantly, this decrease in variation is correlated with an increase in frailty.
Reduced diversity of intestinal microbiota is also found in patients with Chron's Disease. It is precisely this kind of data that keeps scientists hopeful and excited about the gut microbiome. It is also only a small sampling of the research being done in this area. The gut microbiome is under investigation for its relationship to many other conditions including obesity and type 2 diabetes.
Having coupled with technology that has allowed active cultures to enter into and survive the rigorous conditions of processing, the enthusiasm for probiotics is not going away. Recently available to the consumer are such items as coffee, chewing gum and baked goods with live bacteria that live through previously impossible levels of heat, acid, pressure and shear.
The market for foods with a natural variety of probiotics, such as yogurt, keifer and a long list of fermented foods that includes traditional staples like sauerkraut and kimchi, continues to increase. The market for foods fortified with prebiotics also is expected to grow as new research comes in.
How specific probiotics can be used to target either prevention or treatment of variety of conditions remains a hot research topic. Still, the most prudent strategy when it comes to feeding and maintaining a healthy gut microbiome remains one of making available a diversity of healthy bacteria across a variety of food choices.