Soluble vs. Insoluble Fiber: What's the Difference?

By now, most of us have heard that eating fiber is good for our health, especially in maintaining bowel regularity and in the prevention of constipation and other digestive ailments. But there are many other health benefits to adding fiber to your daily diet.

First, it's important to know the difference between soluble and insoluble fiber, both of which are good for your health, but each type serves a distinct purpose and can be found in different foods. Soluble fiber attracts water and turns into a gel-like substance during digestion, slowing the digestive process. It can also help lower cholesterol and glucose (sugar) levels. Soluble fiber is found in oat bran, barley, nuts, beans, lentils, and some fruits and vegetables. Insoluble fiber adds bulk to the stool and can help food pass more quickly through the stomach and intestines. Insoluble fiber can be found in wheat bran, vegetables and whole grains.

The best way to ensure that you're getting sufficient amounts of both types of fiber is eating a diet that's rich in whole-grains, fruits, vegetables and legumes and avoiding processed foods, including white bread and pasta.

According to the National Academy of Sciences' Institute of Medicine, women 50 and younger should aim for 25 grams of fiber a day, and women over 51 should get 21 grams. Men 50 and under should strive for 38 grams of fiber per day and men over 50 should get 30 grams. Just keep in mind that while getting adequate amounts of fiber in your diet is good for long-term good health, adding too much fiber to your diet too quickly can result in bloating, cramping and intestinal gas.

Getting Your Daily Dose of Fiber

To get more fiber in your diet, try sticking to an eating plan similar to the Mediterranean diet, which includes more fish and less red meat and high amounts of fruits, vegetables, and legumes and healthy fats like olive oil. Some additional sources of foods high in insoluble fiber include:

  • Dark green vegetables such as green beans and Brussels sprouts
  • Cabbage
  • Beets
  • Carrots
  • Turnips
  • Apple skin

Some additional foods high in soluble fiber include:

  • Oat bran
  • Rice bran
  • Citrus fruits
  • Strawberries
  • Apple pulp

Before making any major changes to your diet, be sure to discuss them with your doctor first to ensure that you're getting all the nutrients you need.