Fiber is one of the main reasons that whole plant foods are good for you. Growing evidence shows that your digestion may benefit from adequate fiber intake and decrease your risk of chronic illness. Your gut microbiota, the millions of bacteria that live in your digestive system, mediates many of these advantages. Not all fiber, however is produced equally. Each type has various effects on health.
What is Fiber?
Put simply, a non-digestible carbohydrate found in foods is dietary fiber.
Based on its water solubility, it is split into two broad categories:
Soluble fiber: It dissolves in water and the "good" bacteria in the gut will metabolize it.
Fiber insoluble: Does not dissolve in water.
Fermentable or non-fermentable is perhaps a more useful way to categorize fiber, which relates to whether or not friendly gut bacteria can use it. Keeping in mind that there are several different types of fiber is important. Some of them though others are largely useless, have significant health advantages.
Soluble and insoluble fibers also have a great deal of overlap. Good bacteria in the intestine can digest certain insoluble fibers, and most foods contain both soluble and insoluble fibers. Health officials suggest that 38 and 25 grams of fiber a day be consumed by men and women, respectively.
Feeds “Good” Gut Bacteria
In the human body, the bacteria that live outnumber the cells of the body 10 to 1. Bacteria are present in the skin, mouth and nose, but the vast majority live in the gut, mainly the large intestine. In the intestine, roughly 500 separate species of bacteria live, totaling about 100 trillion cells. These gut bacteria are sometimes referred to as the flora of the gut.
It's not a bad thing here. In fact, between you and some of the bacteria that live in your digestive system, there is a mutually beneficial relationship. You provide the bacteria with food, shelter and a stable habitat. In return, they take care of certain things that cannot be achieved on their own by the human body.
Some of the many different types of bacteria, including weight, blood sugar regulation, immune function and even brain function, are important for different aspects of your health. You may wonder what fiber has to do with this. Bacteria need to eat to get nutrients to live and work, just like any other organism.
The issue is that before they make it to the large intestine, most carbohydrates, proteins and fats are absorbed into the bloodstream, leaving nothing for the gut flora. This is when it comes to fiber. Human cells do not have the enzymes to absorb fiber, so it remains largely unchanged in the large intestine.
Intestinal bacteria do however have the enzymes to digest all of these fibers. This is the most significant explanation for the importance of some) dietary fibers for wellbeing. In the intestine, they feed the "good bacteria, acting as prebiotics.
In this way, they encourage the production of "good" gut bacteria, which can have different beneficial health effects. Friendly bacteria produce the body's nutrients, including short-chain fatty acids such as acetate, propionate and butyrate, the most important of which tends to be butyrate.
The cells of the colon can be fed by these short-chain fatty acids, contributing to decreased inflammation of the gut and changes in digestive disorders such as irritable bowel syndrome, Crohn's disease and ulcerative colitis.
As the fiber is fermented by bacteria, they often create gases. This is why in certain individuals high-fiber diets can cause flatulence and stomach discomfort. When the body changes, these side effects normally go away with time.
Can Help You Lose Weight
Certain types of fiber can help you lose weight by reducing your appetite. In fact, some studies show that by immediately reducing calorie intake, increasing dietary fiber can cause weight loss. In the intestine, fiber will soak up water, slowing nutrient absorption and increasing feelings of fullness.
This does, however, depend on the form of fiber. There is no effect on weight for certain forms, although some soluble fibers may have a major effect. Glucomannan is a good example of an effective fiber supplement for weight loss.
Can Reduce Blood Sugar Spikes After a High-Carb Meal
High-fiber foods appear to have a lower glycemic index than processed carbohydrate sources, which have been stripped of much of their fiber. However, scientists agree that only high-viscosity, soluble fibers have this property. Having these viscous, soluble fibers in carbohydrate-containing foods can cause smaller spikes of blood sugar.
This is significant particularly if you follow a high-carb diet. In this case, the fiber can reduce the risk that carbs will increase your blood sugar to harmful levels. That said, if you have problems with blood sugar, consider reducing your carbohydrate intake, especially low-fiber, processed carbs, such as white flour and added sugar.
Can Reduce Cholesterol, but the Effect Isn’t Huge
Your cholesterol levels can also be lowered by viscous, soluble fiber. The impact, though isn't almost as impressive as you would think. A analysis of 67 controlled studies showed that eating 2-10 grams of soluble fiber per day only decreased total cholesterol by 1.7 mg/dl per day and, on average, LDL cholesterol by 2.2 mg/dl.
But this also depends on the fiber's viscosity. With increased fiber consumption, some studies have observed remarkable reductions in cholesterol. It is unclear if this has any major long-term consequences, although several observational studies suggest that people who consume more fiber have a lower risk of heart disease.
Fiber and Constipation
Reduced constipation is one of the principal advantages of rising fiber intake. It is believed that fiber helps to absorb water, increase the bulk of your stool and speed up your stool's passage through the intestine. The proof is however, fairly contradictory.
Some studies indicate that rising fiber may improve constipation symptoms, but other studies show that constipation is improved by eliminating fiber. The effects are depending on the fiber type. In one study of 63 people with chronic constipation, their problem was solved by going on a low-fiber diet. The people who stayed on a high-fiber diet saw little change.
In general, fiber that raises the water content of the stool has a laxative effect, while fiber that adds to the dry mass of the stool can have a constipating effect without increasing its water content. It is also effective to have soluble fibers that form a gel in the digestive tract and are not fermented by gut bacteria. Psyllium is a good example of a gel-forming fiber.
By drawing water into the colon, other fiber types, such as sorbitol, have a laxative effect. A good source of sorbitol is prunes. Choosing the right form of fiber can improve your constipation, but you can do the opposite by taking the wrong supplements.
For this purpose, before taking fiber supplements for constipation, you can consult with a health professional.
Might Reduce the Risk of Colorectal Cancer
Colorectal cancer is the world's third leading source of cancer deaths. Several studies have linked a high intake of foods rich in fiber to a decreased risk of colon cancer. Whole, high-fiber foods such as fruits, vegetables and whole grains, however, contain numerous other beneficial nutrients and antioxidants that can influence the risk of cancer.
It is also difficult to distinguish the effects of fiber in balanced, whole-food diets from other influences. No strong evidence to date shows that fiber has cancer-preventive effects. However, since fiber can help keep the colon wall safe, fiber plays an important role, many scientists believe.
To Sum It Up
There are several health advantages of dietary fiber. Fermentable fiber not only feeds the gut bacteria, it also forms short-chain fatty acids that nourish the colon wall.
Additionally, after high-carb meals, viscous, soluble fiber will decrease your appetite, lower cholesterol levels and decrease the increase in blood sugar. You should make sure to get a lot of fiber from whole fruits, vegetables and grains if you are looking for a balanced lifestyle.