From Chapter Six: Feeding the Germs of Fermentation Well with Prebiotics
Prebiotics are dietary substances from the carbohydrate family that encourage the activity and multiplication of the germs of fermentation. They come in the form of plant fiber that cannot be digested by human beings but can be digested by the germs of fermentation, particularly those that reside in the lower part of the small intestine and in the ascending colon.
Please Note: It is important to not confuse prebiotics for probiotics. Probiotic is the name that is given to those intestinal germs whose activity is beneficial for our health. Prebiotics are the foods that nourish these germs.
Two Kinds of Fiber
Prebiotics are plant fibers, but this does not mean that all the fiber contained in the foods we eat are prebiotics, nor that foods that are high in fiber are necessarily a rich source of prebiotics. In fact, a distinction is made between two kinds of fiber.
Insoluble fiber is the fibers that form the protective envelope of cereal grains (the pericarp or bran) or the substance that makes the plant structure stiff, such as the stem, for example. These fibers appear in the form of cellulose. They are hard and coarse, and for this reason they are a source of irritation for the intestinal walls when too much insoluble fiber is present in the foods consumed.
Insoluble fiber is composed of chains of glucose that can include anywhere from 10,000 to 25,000 units. Because of their length and their insoluble nature, these fibers cannot be broken down into smaller particles, which is to say they cannot be digested by the germs of fermentation. For that reason they cannot get any nourishment from insoluble fiber, which is why insoluble fiber is not prebiotic. Its role in the intestines is to provide roughage that contributes to a healthy intestinal transit.
Keep in Mind: Roughage Has No Prebiotic Properties
Wheat bran and oat bran are recommended as roughage to fight against constipation because they are both so high in fiber. They consist of 43% and 15% fiber respectively. However, the fiber they contain is insoluble fiber, therefore it has no prebiotic properties.
Soluble fiber is composed of short chains of glucose; these chains consist of as little as two to no more than twenty units of glucose. The simple nature of these chains makes them easily digestible by the germs of fermentation. Furthermore, the soluble nature allows these germs to easily transform through the processes of hydrolysis and fermentation. Because soluble fiber is able to be used as food by the germs of fermentation, it is prebiotic.
The Different Kinds of Soluble Fiber
Soluble fibers are very small in size, which often means they are not visible to the naked eye. They play a role in the formation of the skin of fruits and vegetables, but they can also appear in their flesh. They are also abundantly present in cereals and beans. There are several different kinds of these fibers.
Pectin is a mucilaginous substance present in many plant foods. It is primarily known as a setting agent for jams and jellies, as one of its characteristics is to swell upon contact with water. This allows it to form a solid mass that makes the jelly less liquid. A food that is well-known for having a high pectin content is the apple.
This substance has a composition close to that of starch, but its structure is much less complex. It consists of a blend of fructose and a variety of other simple sugars. Inulin can be found in many plants, but particularly in chicory roots and in the tubers of Jerusalem Artichokes.
The Oligosaccharides (FOS)
These fibers are composed of fructose and other simple sugars. They are found primarily in fruits, but they are also found in beans and in the seeds of whole grain cereals.
The Galactooligosaccharides (GOS)
These fibers consist of galactose in combination with other simple sugars. Galactooligosaccharides are the form in which plants store carbohydrates as a reserve fuel. This is why they are primarily found in the seeds of leguminous plants (green beans, red beans, Lima beans, lentils, and so on) and in the lower portions of plants (beetroot, onions, Jerusalem artichokes, and so on).
Foods That Are Sources of Prebiotics
All fruits provide useful prebiotics for our intestinal flora, whether they are common fruits to Europe and North America like apples, pears, and grapes, or if they come from more tropical regions like grapefruit, pineapple, oranges, bananas, and so on. These fruits can all be consumed fresh to enjoy their benefits, but they are just as helpful when dried. Dried fruits would include dates, figs, raisins, apricots, prunes, and many more.
Instructions for Using Fruits
Fruits are an ideal food for snacks because they provide energy because of the carbohydrates they contain. They are able to lift the energy levels of the physical organism without demanding any great effort of the body because they are easy to digest. They also make it possible to avoid eating bad sugars such as those found in chocolate or pastries. The sugars in these foods place a much heavier demand on the digestive functions and contribute toxins.
Did You Know? Honey, thanks to its FOS content, also has a prebiotic effect.
Another source of prebiotics is cow’s milk. In fact, cow’s milk contains 4.7 grams of carbohydrates per liter in the form of lactose. This is a bisaccharide that is made up of equal parts of galactose and glucose. It is the same galactose that is found in GOS and in OHM. The digestion of lactose can release galactose that can then be used as a prebiotic for the intestinal germs. Whey, which is a byproduct of milk, is rich in lactose and for this reason has been long used successfully as a means of regenerating the intestinal flora.