Digestive Wellness|Fiber Facts|Food & Nutrition

Soluble vs. Insoluble Fiber: Which Is Better for You?

You probably know that dietary fiber is an essential part of a healthy diet, but did you know that there are different types of fiber? Yup, there are two types of fiber, soluble and insoluble. They have unique functions in the body, and benefit your health in their own way, too. Read on to learn more about the differences between soluble and insoluble fiber, and whether or not one is better for you than the other.

First, what is dietary fiber?

Dietary fiber is a naturally occurring component of plant-based food that can’t be broken down by our digestive systems. It passes right on through the gut, aiding the digestive process along the way. You probably know it best for helping you poop, but dietary fiber plays other roles that benefit gut health. For example, it helps you digest saturated fats by promoting the production of bile. Dietary fiber also helps you feel more full between meals, and may regulate your blood sugar levels.

Due to the many advantages of getting enough fiber in your diet, doctors and experts recommend it to help lower the risk of diabetes, cardiovascular disease, and high blood pressure. It’s also associated with preventing constipation, hemorrhoids, and colon cancer. 

What is the difference between soluble fiber and insoluble fiber?

Soluble fiber is able to dissolve in water and gastrointestinal fluids. When it does so, it turns into a gel-like substance once it reaches the colon. This then gets digested by the gut microbiota, which are friendly microorganisms that keep your gut healthy.

Due to the many advantages of getting enough fiber in your diet, doctors and experts recommend it to help lower the risk of diabetes, cardiovascular disease, and high blood pressure.

Insoluble fiber doesn’t dissolve in water, but absorbs it. In doing so, it helps bulk up your stool.

Which is better: soluble fiber or insoluble fiber?

Both soluble and insoluble fiber have advantages for your digestive system, as well as your overall health.

Benefits of soluble fiber include:

  • Lowering fat absorption and helping weight management: As a thick, spread-out gel, soluble fiber blocks fats that would otherwise be digested and absorbed.
  • Lowering cholesterol: Soluble fiber prevents some dietary cholesterol from being broken down and digested. Over time, soluble fiber can help lower cholesterol levels or the amount of free cholesterol in the blood.
  • Stabilizing blood sugar (glucose) levels: Just as it prevents fats from being absorbed, soluble fiber slows down the digestion rate of other nutrients, including carbohydrates. This means meals containing soluble fiber are less likely to cause sharp spikes in blood sugar levels and may prevent them.
  • Reducing the risk of cardiovascular disease: By lowering cholesterol levels, stabilizing blood sugars, and decreasing fat absorption, regularly eating soluble fiber may reduce the risk of heart disease and circulatory conditions.
  • Feeding healthy gut bacteria: Some soluble fiber-rich foods feed gut bacteria, as it is fermentable in the colon, and so it helps the bacteria thrive longer.

On the other hand, benefits of insoluble fiber include:

  • Preventing constipation: As an indigestible material, insoluble fiber sits in the gastrointestinal tract, absorbing fluid and sticking to other byproducts of digestion that are ready to be formed into the stool. Its presence speeds up the movement and processing of waste, helping prevent gastrointestinal blockage and constipation or reduced bowel movements.
  • Lowering the risk of diverticular disease: By preventing constipation and intestinal blockages, insoluble fiber helps reduce the risk of developing small folds and hemorrhoids in the colon. It may also reduce the risk of colorectal cancer.
  • Not increasing your calorie intake: Since insoluble fiber doesn't dissolve in water or gastrointestinal fluids, it doesn't get broken down by the body and therefore doesn't release calories. 

Even with all of these benefits, certain digestive conditions may require you to consume only one type of fiber in order to avoid exacerbating your symptoms. For example, some IBS and ulcerative colitis patients are advised to consume only soluble fiber in order to avoid exacerbating their symptoms.

How can I get more soluble and insoluble fiber in my diet?

The FDA has recommendations for how much fiber you should consume daily: 25 grams for women and 38 for men. Unfortunately, only about 5 percent of Americans actually get that much fiber a day, whether soluble or insoluble. You can easily get more fiber by making adjustments to your diet. 

These are some of the foods you can eat to get more soluble fiber in your diet:

  • Dried beans
  • Oats
  • Rice bran
  • Barley
  • Citrus fruits
  • Apples
  • Strawberries
  • Peas
  • Potatoes

Here are some foods you can eat to increase your insoluble fiber intake:

  • Wheat bran
  • Whole grains
  • Cereals
  • Seeds
  • The skin of many fruits and vegetables

Additionally, you can take a supplement every day to keep your fiber intake on track. Bellway’s all-natural fiber supplements give you 18 percent of the fiber you need daily, plus it has the added benefit of containing no artificial ingredients. (Just note that it’s made with psyllium husk fiber, which is soluble.) As with any supplement, check with your doctor before adding it to your daily routine.