Fiber Food Sources Benefits And Side Effects -

Fiber Food Sources Benefits And Side Effects

Fiber Food Sources Benefits And Side Effects


Fibers are indigestible carbohydrates primarily derived from various plant sources, including fruits, cereals, grains, and vegetables. They are made of materials like cellulose and lignins which cannot be digested. From the small intestine, they pass directly to the large intestine where only a part of this fiber is fermented by the gut bacteria.


So, why do we need fiber in the first place?

Fiber is essential for providing bulk food and regulating bowel movements. Being undigestible, it stays in your gut and makes you feel full for a longer period thus increasing the gap between your meals. This is especially helpful for diabetics as less frequent meals can help maintain blood glucose levels.

Additionally, a diet rich in fiber would keep your stomach healthier and help reduce the risk of problems like obesity, constipation, colon cancer, piles, and heart diseases.

The many health benefits of dietary fibers have earned it the title of “functional food” by the American Council of Cereal Chemists.

  • Types of dietary fiber
  • Fiber-rich foods and sources
  • Fiber health benefits
  • Fiber side effects
  • Takeaway

Types of dietary fiber

Dietary fiber can be classified into two types:

1. Insoluble dietary fiber

Insoluble dietary fiber, as the name suggests, does not dissolve in water. They bind with the water in your intestines and provide bulk to the food. Foods rich in insoluble fiber would thus increase the transit time (the time for which food stays in the intestine) and make you feel full for longer. Insoluble fibers help in:

  • regulating bowel movement
  • reducing constipation
  • losing weight

Insoluble fiber is more commonly found in fruit peels, wheat bran, cereals, etc.

2. Soluble dietary fiber 

Soluble fibers can dissolve in water and turn into a gum or gel-like substance in the intestines. They are mainly found in fruit pulps, barley, seeds, and nuts.

Some soluble dietary fibers are fermented (breakdown of carbohydrates by the action of microorganisms) in the intestines and thus are responsible for modulating the microflora of the gut. Since a huge proportion of our food is digested by gut microbes, eating a particular type of fiber may be the deciding factor in the health of your gut. Soluble fibers also help in:

  • reducing cholesterol levels in the body
  • reducing blood glucose levels

Fiber-rich foods and sources

Fiber is naturally present in the whole grain diet including wheat, wheat bran, oat bran, fruits, and vegetables. According to the Asian Journal of Pharmaceutical and Clinical Science, the daily recommended intake of fiber ranges from 25-30 g/day which can be achieved by consuming more cereals, grains, and plant-based products.  If you take a vegetarian diet, it’ll most probably cover your daily fiber intake. However, a non-vegetarian diet lacks fiber, so you must take a balanced diet by adding more fruits and vegetables to it.

Here is a list of fiber-rich foods that you can easily add to your diet:

  • Whole grains like wheat, oats, and quinoa
  • Psyllium husk
  • Oat bran
  • Wheat bran
  • Lentils
  • Beans (french beans, mung beans, black beans, kidney beans)
  • Soybean
  • Most Fruits (apples, pears, figs, raspberries, oranges, bananas)
  • Dates
  • Pistachios
  • Pecans
  • Almonds
  • Hazelnuts
  • Peanuts
  • Vegetables like carrots, beets, broccoli, artichokes, and potatoes

You should always consult a dietician or nutritionist to know the right amount and sources of fiber for your diet.

Fiber health benefits

Fiber-rich foods have several health benefits. It can help you reduce weight, lose cholesterol and regulate insulin levels in the body. However, the most important benefit of a high-fiber diet lies in its use in reducing constipation and regulating bowel movements. Furthermore, it is very helpful in reducing the risk of conditions like piles and cardiovascular diseases. Let us look into some of the health benefits of fibers.

Relieves constipation: Fibre provides bulk to the food and helps softens stool thus promoting easier passage through the gastrointestinal tract. It also promotes healthy bacteria in the gut which facilitate proper and easier digestion of food, thus preventing constipation.

Relieves piles symptoms: By alleviating constipation, fiber helps in reducing the excess pressure on anal walls, thereby, relieving piles symptoms.

Promotes weight loss: Taking a sufficient amount of fiber in your diet help reduce hunger pangs by making you feel full for longer. It has been evidenced that a fiber-rich diet is more efficient in reducing weight than some of the complex diet plans.

Reduces cholesterol: Research evidence indicates that a fiber-rich diet helps in reducing the levels of low-density (bad) cholesterol through an unknown mechanism. It also produces short-chain fatty acids in the intestines, which reduce total cholesterol by interfering with lipid metabolism.

Promotes heart health: Consuming the recommended amount of dietary fiber is conducive to a healthy heart by removing the excess cholesterol from the body and reducing blood pressure levels. It also reduces the risk of atherosclerosis and heart attack.

Regulates blood sugar levels: Though fiber is a type of carbohydrate, it doesn’t get easily digested or absorbed in the intestines. Thus, avoiding the sudden peak in blood glucose after a meal.

  • Fiber for constipation
  • Fiber for weight loss
  • Fiber for cholesterol
  • Fiber reduces blood pressure
  • Fiber for heart health
  • Fiber for diabetes
  • Fiber prevents colorectal cancer
  • Fiber for piles

Fiber for constipation

A fiber-rich diet goes a long way in improving gut health and reducing constipation. The most common benefit of fiber is that it gives bulk to the food and softens the stools. But, various kinds of fibers may have different effects on the gastrointestinal tract. The fiber content in your food may increase or decrease the transit time that is taken by food to pass through the gut. It can also affect the type of bacteria that grow inside your intestines thus regulating the digestion of food.

Studies suggest that ingestion of high-soluble fibers leads to an increase in the numbers of intestinal bacteria like Lactobacillus and Faecalibacterium. Both of these bacteria are very useful in maintaining a healthy gut and aid in the proper digestion of food.

A meta-analysis of RCTs (Random Clinical Trials) in 2012 confirms that the addition of an optimum amount of fiber is very beneficial in reducing constipation.

Fiber for weight loss

Do you know that intake of high dietary fiber can help you lose weight? The insoluble fiber is known to add bulk to your food and increase the colon transit time thus making you feel full for a longer period. It leads to a decreased appetite which ultimately aids in weight loss.  According to a study published in the Annals of Internal Medicine, taking the daily recommended dosage of fiber is much more efficient in reducing obesity as compared to some of the complex diet plans.

Fiber for cholesterol

Numerous studies have been done to assess the role of high-fiber diets in maintaining body health. In all these studies, it was found that the administration of a fiber-rich diet leads to a significant reduction in the levels of low-density lipoprotein (bad cholesterol) and triglyceride fats. However, no apparent effect has been noted in the high-density lipoprotein (good cholesterol) so far.

The exact mechanism by which soluble fibers help to maintain healthy body cholesterol isn’t yet completely understood. But, recent research claims that it may act as a hypocholesterolemic (reducing body cholesterol levels) by interfering with the bile metabolism in the body.

Furthermore, some types of fibers undergo fermentation in the intestines to form short-chain fatty acids (SCFA) like acetate and butyrate. These SCFAs are known to reduce the body’s cholesterol levels by interfering with the metabolism of lipids in the body.

Fiber reduces blood pressure

When it comes to the effects of fiber intake on blood pressure, the evidence is not clear. Although a fiber-rich diet has been associated with lower arterial blood pressure in animal models, individual studies on different fiber sources would be more informative. In a pilot study, the consumption of oats has been found to reduce systolic and diastolic blood pressure in hypertensive people (people suffering from high BP).

According to a meta-analysis published in Nutrition Metabolism and Cardiovascular diseases, an average dose of 9g fiber per day for about 7 weeks has been reported to reduce blood pressure in people suffering from hypertension. Additionally, it suggests that a higher fiber diet is more beneficial in reducing blood pressure for hypertensive people as compared to the healthy.

Fiber for heart health

Cardiovascular diseases are one of the leading causes of mortality all over the world. While the exact mechanism of action of dietary fiber has not yet been found, it has been strongly associated with a reduced risk of cardiovascular diseases like coronary heart disease.

A fiber-rich diet has also been found to alleviate conditions like high blood pressure, obesity, and hypercholesterolemia which are directly linked to conditions like atherosclerosis, heart attack, and stroke.

Fiber for diabetes

Concerning the efficiency of a carbohydrate-rich diet in reducing blood sugar levels, the responses are quite controversial. Even though fibers are a type of carbohydrate, they cannot be readily digested and absorbed by the body. Thus, a high-fiber diet does not increase blood glucose levels. Soluble fibers have been suggested to regulate the levels of glucose in the blood by an unknown mechanism.

Furthermore, insoluble fibers reduce the glycemic index (amount of sugar converted to glucose in the blood) by increasing the transit time in the intestines.

Fiber prevents colorectal cancer

Numerous studies have been done to test the efficiency of dietary fiber in the prevention of colorectal cancer. According to a systematic review, intake of fiber-rich foods, like cereals and whole grains is protective against colorectal cancer. The World Cancer Research Fund has associated dietary fiber with a reduced risk of colorectal cancer.

Although the exact mechanism of action or the cancer stage at which fiber acts is quite unclear, studies have suggested that the consumption of a fiber-rich diet is negatively correlated with colorectal cancer.

Fiber for piles

Piles or hemorrhoids are associated with abnormally high pressure in and around the anus leading to inflamed blood vessels. According to NIH, factors like obesity, long-term constipation, and a low-fiber diet could be the reasons behind swollen hemorrhoids. Consuming a fiber-rich diet would thus help alleviate some of the symptoms of piles.

Research suggests that fibers soften stools and help them easily pass through the intestine. This would not only reduce constipation but also the excess pressure on anal walls, thus providing relief from piles.

Fiber side effects

Taking a fiber-rich diet along with low water intake can lead to the blocking of the intestines. So, if you want to reap the constipation-relieving benefits of a high-fiber diet, you should keep your water intake in check.

Some types of fibers are fermented in the intestine, leading to an increased risk of bloating and gas.

High fiber diet is a known hypoglycemic (reduces blood sugar levels), so diabetic people are suggested to check with their doctor to know the right kind of fiber.

fiber is an efficient hypotensive (reduces blood pressure). People who suffer from low blood pressure or are hypertensives on medication should talk to a nutritionist before taking fiber supplements.

Some studies suggest that the intake of high dietary fiber leads to reduced absorption of minerals like iron and zinc.


A fiber-rich diet is very important for the proper functioning of the gut and bowels. It not only relieves constipation but also helps you to reduce weight. However, an excess of fiber may lead to constipation and reduced blood sugar levels.

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