Fiber plays a key role in your body. Fiber reduces the absorption of cholesterol, thus preventing cardiovascular disease, and reduces blood glucose, which should be appreciated by people with diabetes. Also, fiber makes you feel full for a long time, and that helps you lose weight.
There are two types of dietary fiber: soluble and insoluble characterized by different activities. In plant products, they occur together but in different proportions.
The fiber is divided into a soluble and insoluble type. Insoluble fiber (cellulose, lignin) from which the cell walls of plants are built acts as a filler.
It absorbs water, but it does not dissolve in it. Thanks to this, it softens the stool, increases its volume, accelerates intestinal motility, regulating bowel movements.
Insoluble fiber fractions act like a broom. They roam the entire digestive tract in a virtually unchanged state, eliminating residual leftovers.
Soluble fiber creates jelly in the intestines. It binds a large amount of water, swells in the stomach, stretches its walls, giving a sense of satiety.
It also delays the moment when food leaves the stomach. The soluble fiber fractions form a delicate gel that fills the stomach and covers the walls of the upper gastrointestinal tract, slowing the absorption of carbohydrates.
This type of fiber also helps to cleanse the body of toxic waste products and heavy metals.
It also has a suppressive effect during diarrhea, reduces cholesterol, increases fat excretion in the feces, and delays the absorption of triglycerides. Soluble fiber is also a nutrient for the development of beneficial bacteria in the gut.
Numerous scientific studies have shown the effect of fiber intake on the risk of cardiovascular disease.
During the 10-year follow-up, about 100,000 men and 245,000 women were tested. It was noticed that an increase in fiber intake, in each of the studied groups, by 10 g per day resulted in a 14% reduction of cardiovascular diseases. The risk of death due to coronary diseases was also reduced by 27 percent.
It has been proved that the increase in dietary fiber intake is inversely proportional to the number of deaths caused by cardiovascular diseases, and such factors as sex, age, environmental factors, physical activity did not have a significant impact on the results.
Dietary fiber has a protective effect on the circulatory system in several ways: it reduces the absorption of fat, lowers cholesterol, reduces the absorption of bile acids, and the production of short-chain fatty acids.
Since the 1980s, research results on the anti-cancer effect of fiber have been published, but they are not always conclusive.
Research in the USA, Finland, and Sweden did not give straightforward evidence of antineoplastic activity of fiber. Other studies have confirmed its anti-cancer properties.
In European studies, Prospective Investigations on Cancer and Nutrition (EPIC) coordinated by the International Agency for Research on Cancer have examined over half a million people to assess the relationship between diet and cancer.
In the published report, the researchers found that in comparison with people consuming 15 g of fiber a day in people who supply 35 g of this component, the risk of cancer was decreased by 40%.
Fiber inhibits the absorption of heavy metals and toxins and accelerates their removal from the body.
Other researchers have published a paper in which they compare the effect of fiber intake on the risk of stomach cancer.
The results from 21 articles that were published until 2012 were analyzed. It was found that an increase in dietary fiber consumption by 10 g/day reduces the risk of gastrointestinal cancer by as much as 44%, which confirms the results of earlier studies.
Dietary fiber can also reduce the risk of breast cancer. Researchers compared the results of 10 scientific studies of 700,000 women in which 16.848 developed breast cancer.
The authors found that among women who consumed higher amounts of dietary fiber, the percentage of cases was lower by 11%. And an increase in fiber intake by 10 g/day reduces the morbidity by 7%.
The anti-cancer effect of fiber may result from its beneficial effects on the functioning of the colon by stimulating the production of new cells, preventing atrophy (disappearance) of the epithelium, improving the passage of food through the intestine, as well as the ability to ferment because of significant amounts of short-chain fatty acids.
In the case of breast cancer, the anti-cancer effect of fiber is attributed to its ability to remove excess estrogen along with feces.
Increasing the content of dietary fiber in meals contributes to lower blood glucose fluctuations, allows you to control your blood sugar level and, so, prevent type 2 diabetes.
American Diabetes Association recommends consumption of at least 14 g / 1000 kcal/day, or 25 to 30 g / day.
It can also help people who are already struggling with diabetes, as shown by scientists from the Medical University of South Carolina, USA.
Their study aimed to answer the question of whether dietary fiber intake may affect the level of HbA1c glycated hemoglobin and glucose in patients with type 2 diabetes. Glucose was measured on a group of 400 patients, while the analysis of glycated hemoglobin was performed on a group of 324 patients.
The results of the study showed that in patients who were recommended to take larger amounts of dietary fiber in the daily diet by an average of 18g/day, there was a significantly greater decrease in glucose concentration by 0.85mmol / L, or 15.32 mg/dl in comparison to patients taking a placebo.
Similarly, in this group of patients, scientists saw 0.26 percent greater decrease in HbA1c glycated hemoglobin levels than in the placebo group.
The authors emphasize that, although the decrease in glycated hemoglobin is not impressive, long-term use of dietary fiber may be more important and complement the pharmacotherapy of type 2 diabetes.
In 2010 EFSA established the daily dose of fiber for adults at 25 g / day, and for children from 10 to 21, g / day depending on age.
According to the World Health Organization (WHO), the daily intake of fiber in adults should be 20-40 g. Do not exceed these doses.
Too much fiber intake in the diet can lead to:
Diseases in which too much fiber intake is inadvisable, e.g., gastritis or stomach ulcers, pancreatitis, bile ducts, intestines or anemia.
The fiber in the presence of water increases its volume and, so, also the volume of stool, facilitating its passage through the intestines and expulsion outside the body.
Also, fiber stimulates intestinal motility, which leads to more frequent, regular bowel movements, and so to the absence of constipation. However, the effectiveness of fiber in this range depends on its type.
The dietary fiber contained in bran, as well as in more processed products, does not show such an effective effect on the intestinal passage as fiber, whose source of food is low-processed and whole-wheat food.
Do not overdo it with the amount of fiber. Remember to drink the right amount of water – otherwise, it may cause constipation.
The effectiveness of fiber in the digestive system also depends on the amount of water consumed. Italian scientists have conducted studies on the effectiveness of dietary fiber on intestinal motility, which was supported by the intake of additional water.
The study group was divided into two control subgroups, which received a standard diet having 25 g of fiber, the first one drinking 1 liter of water/day and the other 2 liters of water/day for two months.
The amount of dietary fiber consumed in the study group increased twice. By the conducted tests, it was found that the frequency of defecation per week increased, however with added supplementation with water, significantly better results were recorded.
Fiber is an effective remedy for constipation, however, remember to carefully select products having the best quality fiber and remember about the appropriate supply of liquids.
Fiber absorbs water, thanks to which consumed foods increase their volume in the stomach, giving a feeling of fullness.
Another function of fiber that affects the feeling of satiety is to slow down stomach emptying and absorption of nutrients. Thanks to this, the feeling of fullness stays longer and stops the urge to eat.
Also, food rich in dietary fiber in most cases also needs increased chewing, because it is harder.
Thanks to this activity the feeling of satiety is also felt faster, because the meal is eaten slowly, and the pieces of food are chewed longer. In this way, fiber supports lose weight.
Check our list of the best sources of fiber
The source of fiber is mainly cereal products from low grain milling, such as high-grade flours (e.g., Graham type 1850), bread and multi-cereal flakes made from them, e.g., natural rye flakes (11.6 g / 100g), rye bread whole grain (6.1 g / 100 g).
The second very good source of fiber are fruits and vegetables – the fruits rich in fiber are especially currants (7.9 g / 100g) and raspberries (6.5g / 100g). They should be consumed in the amount of 5 portions/day.
It is recommended to consume seeds between meals instead of sweets, e.g., sunflower seeds (8.6 g fiber / 100 g), pumpkin seeds (6 g fiber / 100 g) and dried fruits such as figs (9.8 g fiber) / 100 g) or apricots (10.3 g fiber / 100 g) and plums (10 g / 100 g).
It is worth paying attention to linseed, which is a very good source of fiber at the level of 27.3 g / 100 g of product.
If so, far you have been avoiding foods rich in fiber, turn them into your diet gradually. It should take a few weeks to reach the recommended dose. A sudden increase in fiber can cause bloating, gas, loose stools.