Fibers have virtually no nutritional value, but soluble and insoluble fibers play an important role in maintaining the health.
Soluble fibers (in fruit, vegetables, oats, nuts and legumes) are made of substances similar to rubber and some other components of plant cells and cell walls with water swelling properties. By the bacteria’s acting in the colon, they break down into simpler compounds. Plantago ovata (psyllium) is often used as a source of soluble fibers. Insoluble fibers (in various types of grains) consist mostly of cellulosic parts of plant cell walls. She does not swell in water, but bind with it; they remain unchanged in the digestive system because they are not absorbed nor degraded by digestive enzymes.
How do they work?
Fibers absorb excess water in the bowel, and the stool becomes abundant and softer. They also bind cholesterol, which is then thrown out from the body, which is useful for reducing its level in blood. Insoluble fibers such as cellulose help the function of the intestine. They also throw out toxins and substances that stimulate the creation of cancer. Although the soluble fibers can not be digested, they are fermented by useful bacteria from the intestine. In this process fatty acids are formed, important for the intestinal tract nutrition.
MAIN USEFUL EFFECTS: the lack of fiber in the diet is associated with numerous degenerative and chronic diseases, including heart disease, diverticulitis and diabetes. A proper meals should contain 18 grams of fiber per day, and most people in the United Kingdom take only 12 grams. One slice of whole grain bread contains five grams of fiber.
A food, rich in fiber, can help in preventing constipation and hemorrhoid by increasing the amount of water in the stool, which makes it easier to excret. Many soluble fibers in the diet may be of benefit to diabetics because the absorption of sugar slows down and thus reduces insulin consumption. This type of fiber also reduces the amount of cholesterol that gets from the bowel to the bloodstream, therefore its volume in blood is smaller. In one study, people with high cholesterol levels took at least 10 grams of psyllium for six weeks. They reduced the level of ”bad” (LDL) cholesterol by 6% to 20%.
Psyllium, as a rich source of soluble fibers, helps regulate the function of the intestine in people who suffer from both diarrhea and constipation. It is good for people with irritable bowel syndrome, where the bowel function varies between these two extremes.
ADDITIONAL USEFUL EFFECTS: some studies have shown the beneficial effect of fiber in weight loss because the absorbed water fills the stomach and the appetite decreases. Likewise, the release of food from the stomach is slowed down. Some types of fiber-rich foods, such as flaxseed, contain plant estrogens, so-called lignans, associated with reduced risk of cancer. This is especially true for breast cancer. Psyllium has a role in preventing gallstones; this has been shown by a Mexican study conducted on obese patients, who had bigger risk of gallstones formation.
How to take it?
DOSAGE: start with small doses, say 1 to 2 grams with each meal. Over time, the amount can be increased to 1 to 3 tablespoons (up to 10 grams) of powder, two to three times a day, with 250 ml of juice or water. Never take more than 30 g per day.
USE GUIDELINES: when using fiber as a dietary supplement, you should drink plenty of fluids because they are absorbed in large quantities. It is advised that you wait at least two hours between taking the fiber and some other medication, so there won’t be interference with the absorption of the drug. Pregnant women should consult a doctor before using fibers.
Possible side effects
Bringing large amounts of fiber can cause inflammation and abdominal pain. Legume can cause strong flatulence, and in some people fibers, especially wheat, cause stomach irritation.
IMPORTANT: large fiber intake may reduce the effectiveness of some drugs, including oral contraceptives and cholesterol-lowering medicines, such as lovastatin.
Tablets or capsules with fiber can be dangerous. When they come into contact with the water they swell and obstruction in the throat or bowels can occur.
If you suffer from a rare psyllium allergy, which causes rash or breathing problems, be sure to seek help from your doctor.