Soluble Fiber: Another Way to Fight High Cholesterol

By Jeanne Cullen, MS, RD, CD, CDE

Fiber may not be the magic health bullet that everyone is looking for, but it might be one of the missing links in your search for a healthy diet.

Most people know that eating ‘roughage’ helps to keep them regular. But did you know that a high fiber diet might help prevent heart disease and diabetes and even promote weight loss?

Most people don’t realize how many benefits a high fiber diet has and how much fiber we should eat.

Fiber is the part of food that cannot be digested or broken down by the human body. It passes through our body intact, cleaning our intestines as it travels through. This is why fiber promotes good intestinal function, although it adds little energy or calories to the diet.

You can think of fiber as a scrub brush for the intestines. Low fiber diets are associated with constipation, irritable bowel syndrome, diverticulosis and colon cancer. High fiber diets tend to prevent these problems and diseases. In the past, these were the main benefits associated with a high fiber diet, but we are now finding other ways that fiber is beneficial. Recent studies have shown that a high fiber diet can reduce the risk of heart disease and diabetes.1

Fiber is found only in foods of plant origin. The best sources of dietary fiber are fruits, vegetables, beans, nuts and seeds, whole grains such as brown rice, barley, wheat berries, oats, quinoa, and whole grain products such as whole wheat breads, pastas and cereals.

There are two different types of fiber: soluble and insoluble. Both types of fiber are important and they each provide different benefits to our health. Certain foods are better sources of one type than the other.

Soluble fiber dissolves and thickens in water. Soluble fiber is probably best known for its cholesterol lowering effect, when eaten as part of a diet low in saturated fat and cholesterol.

  • Soluble fiber is made up of sticky substances like gums and pectin, which form a gel-like substance in the presence of liquid. The gel binds with cholesterol and bile acids in the small intestine and eliminates them from the body. Bile acids are made from the cholesterol that is stored in our blood, so more of your body’s cholesterol is used up in replenishing the bile acids.

  • Soluble fiber also helps to stabilize blood sugar and control diabetes, by slowing the absorption of carbohydrates and reducing the rise of blood sugar after a meal.

  • Soluble fiber also provides a feeling of fullness, so it can potentially help with weight loss. The best sources of soluble fiber are oats, especially oat bran, barley, dried beans, soybeans, sweet potato and white potato, broccoli, asparagus, carrot, apple, pear, citrus fruits, berries, banana, almonds, psyllium and flax seeds.

The first fiber health claim approved by the FDA was for oatmeal.2 It said “Soluble fiber from oatmeal, as part of a low saturated fat, low cholesterol diet, may reduce the risk of heart disease.” Beta-glucan is the name of the soluble fiber found in oats. Studies have shown that 3 grams of beta-glucan per day are needed to reduce cholesterol. This would be the amount in 1 cup of cooked oat bran, 1½ cups of cooked oatmeal or 3 cups of instant oatmeal. As you can see, the more processed the food, the more you have to eat in order to reach the recommended level of soluble fiber.

Insoluble fiber does not dissolve in water. It absorbs water as it passes through the body, which adds bulk to the stool and speeds up transit time, preventing constipation and diverticulosis.

  • It also helps reduce the risk of colon cancer by moving toxins and cancer causing substances through the digestive tract more quickly.

  • The best sources of insoluble fiber are wheat bran and wheat products. Most plant foods contain both types of fiber. Insoluble fiber is more common, found in most fruits and vegetables as well as beans, grains and nuts.

So, how much fiber do we need to reap all these benefits? The American Dietetic Association recommends that people eat between 20 – 35 grams of total fiber daily, and of that, 5 – 10 grams should be soluble fiber.3 The National Cholesterol Education Program (NCEPIII) claims that we should be eating as much as 10 – 25 grams of soluble fiber/day.4

Unfortunately, recent studies have shown that most Americans only get about 10 – 12 grams of total fiber, and about 3 - 4 grams of soluble fiber daily. Not nearly enough. So how can we increase fiber on a regular basis? It is not as hard as you might think, especially when you eat foods as close as possible to the way nature intended for us to eat them.

Here is a sample meal plan that will provide the recommended amount of fiber for one day. 4, 5 Any change to your meal plan should be discussed first with your doctor, because if the carb counts change for each meal, your mealtime insulin doses may need to be adjusted.

Breakfast Total fiber Soluble fiber
1 cup cooked Scottish or steel cut oats 8 2
1 small apple, chopped 3.7 1.1
1 Tbsp. slivered almonds 0.9 -
½ tsp. Cinnamon - -

1 cup bean soup 9 2.1
1 sandwich on whole wheat bread 2.9 1.0
w/ turkey, lettuce, tomato, light mayo, mustard <1 -
Small handful of baby carrots 2.2 0.5

4 – 5 oz. fresh fish or lean meat - -
1 cup broccoli 5.2 1.6
½ small sweet potato (approx. 1 cup) 1.7 0.5
Salad w/baby greens, carrots, tomato <1 -

½ cup cottage cheese and 1 pear 2.5 0.6
1 slice of oat bread and almond butter 3.6 <1
Total 39.7 9.4

As you can see, if you eat a variety of fruits and vegetables throughout the day, along with a serving of beans, 5-6 servings of whole grains, a source of protein at every meal and a few healthy snacks, you are well on our way to having a balanced diet and meeting your fiber goals.

Here are some more tips to help you increase fiber in your diet. Good luck and good eating!

  • Eat some form of whole oat cereal or other high fiber cereal at breakfast. Look for at least 5 grams of fiber per serving on the label.

  • Eat fresh fruit with breakfast and at snack times, instead of drinking juice.

  • Use whole grain products, such as whole-wheat pasta, tortillas and breads and whole grains such as brown rice, instead of refined grains and products.

  • Add vegetables to sandwiches, pizza, pasta, soups and other entrees.

  • Try to eat beans a couple of times per week, in the form of chili, soup or adding garbanzo or kidney beans to your salad.

  • Have a handful of nuts as a healthy snack or garnish salads with a tablespoon of sunflower or pumpkin seeds.

  • Increase fiber gradually, over several weeks/months and make sure to drink plenty of water as you increase fiber in your diet. 

  • If you are on a low carbohydrate diet, you may need to take a fiber supplement. The FDA has approved a health claim on soluble fiber from psyllium seed husk, much like the one for oats discussed above. It states that 7 grams of soluble fiber from psyllium is needed to lower LDL cholesterol. Metamucil® is a fiber supplement made from psyllium. One packet of Metamucil contains 2.4 grams of soluble fiber. Sugar-free Metamucil is available.


Jeanne Cullen, MS, RD, CD, CDE is a Certified Diabetes Educator and trained Chef from the Culinary Institute of America. She received her Master's degree in nutrition from Bastyr University. Jeanne resides in Seattle, Washington where she combines her love of cooking and whole foods philosophy to work with prevention and management of chronic diseases. She specializes in diabetes education because she knows good nutrition practices can have such a positive outcome. Jeanne is employed at Tacoma General Hospital and the Bastyr Center for Natural Health.

Metamucil is a registered trademark of the Proctor and Gamble Company


1. Van Horn L, Ernst N, A summary of the science supporting the new National Cholesterol Education Program dietary recommendations: What dietitians should know. J Am Diet Assoc, October 2001, 1148-1154.
4. Pennington, Jean, Bowes and Church’s Food Values of Portions Commonly Used, Lippincott Williams and Wilkins,1998.

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