The Benefits of High-Fiber Foods for Thyroid Patients

high-fiber foods

For thyroid patients, a high-fiber diet can be of particular benefit in two key ways: fiber can aid in weight loss for thyroid patients, and can help with chronic constipation, a common thyroid-related complaint. It's helpful to understand the role of fiber. Learn more about the different types of fiber and the foods that are rich in fiber that you can add to your healthy diet.

Understanding This Important Nutrient

Fiber (sometimes spelled fibre) is also commonly known as “roughage.” Dietary fiber describes plant-based foods that are not digested or absorbed.

 There are two kinds of fiber—soluble and insoluble.

Most of the foods you eat–which include carbohydrates, fats, and proteins–are broken down and absorbed by your body–except for fiber. The stomach is unable to digest fiber. Fiber passes through the body–first the stomach, then the small intestine, followed by the colon, and finally, it exits the body– virtually untouched.

Fiber is thought to help slow digestion and the post-meal increase in blood sugar. It helps prevent the build-up of toxins in your intestines by keeping bulk moving through the digestive tract. By binding to bile, fiber can lower cholesterol and help keep arteries clearer of plaque buildup. 

Benefits of Fiber

In general, there are many benefits of a diet high in fiber. Fiber can: 

  • Reduce the risk of stroke and improve your heart health: An important connection has been found between fiber intake and heart attacks. Studies show that patients eating a high-fiber diet decrease their risk of heart attack by up to 40 percent. Your risk may be decreased by 9 percent for each 7 grams per day increase in dietary fiber, according to studies quoted by the Academy of Nutrition and Dietetics in their position paper.
  • Aid in weight loss and management: The more fiber in your daily diet, the lower your risk of obesity. This is likely because fiber makes you feel full, which means you are likely to eat less. Fewer calories each day can eventually lead to weight loss over time.
  • Lower cholesterol: The soluble fiber found in certain beans, flaxseed, oat bran, and oats may help lower “bad” cholesterol levels. This can also lead to less heart inflammation and reduced blood pressure levels.
  • Improve digestion: Dietary fiber helps control the digestion of other foods.
  • Reduce hemorrhoids: By eating a high fiber diet, hard stools and constipation problems may be solved, along with a reduction in your risk and severity of hemorrhoid symptoms.
  • Regulate bowel movements: Fiber can help soften the stool. It also increases the weight and size of the stool. This can help relieve constipation
  • Help control blood sugar levels: People with diabetes on a high-fiber diet have shown that their absorption of sugar is slowed. This helps promote better glucose levels. In­sulin sensitivity may be improved with certain dietary fibers. Eating a high-fiber diet may also decrease your chances of developing type 2 diabetes.
  • Reduce your risk for diverticulitis: Insoluble fiber has been shown to reduce the risk of diverticulitis. However, for those with diverticulosis or irritable bowel disease, some people have worse symptoms with more fiber, while others have fewer symptoms.
  • Relieve irritable bowel syndrome (IBS): Fiber has been shown to decrease IBS symptoms in some people, although others have more symptoms when eating more fiber.
  • Reduce colon cancer risk: Some promising studies have shown that a high-fiber diet may decrease risks of colorectal cancer, but this is not found in every study.
  • Increases mineral absorption: Dietary fiber may help your body to absorb certain minerals more effectively, especially calcium.

Recommendations and Types

The Academy of Nutrition and Dietetics recommends adult women consume 25 grams of total fiber per day and adult men consume 38 grams, with 10 to 15 grams coming from soluble fiber. As you age, you need less and over age 50, women should consume 21 grams and men should consume 30 grams.  

Soluble Fiber: Soluble fiber is fiber that is easily dissolved in water, where it forms a gel-like substance. This type of fiber has been shown to help lower blood cholesterol levels as well as blood glucose levels.

Soluble fiber is found in:

  • Apples
  • Barley
  • Beans
  • Carrots
  • Citrus fruits
  • Flour, corn
  • Hazelnuts
  • Jicama
  • Mixed vegetables (frozen)
  • Oats
  • Okra, cooked
  • Onion (white, yellow, red, cooked)
  • Parsnips
  • Pears
  • Prunes
  • Peas, cooked
  • Soy flour*
  • Yams (canned with syrup, drained)

Insoluble Fiber: Insoluble fiber is a fiber that helps speed up elimination from the body. Insoluble fiber can help prevent constipation. Insoluble fiber also helps keep the pH level in your intestinal tract at an optimum level. The foods that are highest in insoluble fiber include the following:

  • Almonds*
  • Apple with skin
  • Baking chocolate
  • Barley, cooked
  • Bran cereal
  • Blueberries
  • Brazil nuts
  • Broccoli*
  • Brussels sprouts*
  • Bulgur
  • Cabbage*
  • Carrots
  • Cauliflower*
  • Cereal party mix, homemade
  • Cherries
  • Chestnuts
  • Coconut
  • Corn nuts
  • Corn
  • Cranberries
  • Elderberries
  • Figs
  • Flax seed
  • Flour, barley, barley bran, barley malt, rye, whole wheat
  • Gooseberries
  • Green beans
  • Guava
  • Hickory nuts
  • Hominy
  • Jicama
  • Kale*
  • Kidney beans
  • Kiwi
  • Kumquat
  • Lentils
  • Macadamia nuts
  • Mandarin oranges
  • Mango
  • Millet*
  • Mushrooms
  • Nectarine
  • Oatmeal
  • Oyster
  • Papaya
  • Pasta, whole wheat, cooked
  • Peanuts*
  • Pears
  • Peas
  • Pine nuts
  • Pineapple
  • Pistachios
  • Potatoes
  • Prunes
  • Pumpkin seeds
  • Pumpkin puree
  • Quinoa
  • Raisins
  • Raspberries
  • Rhubarb
  • Rice (brown, cooked)
  • Rutabaga
  • Sauerkraut
  • Sorghum
  • Spinach
  • Split peas
  • Sprouts
  • Squash
  • Strawberries
  • Sunflower seeds
  • Sweet potato
  • Tomato paste
  • Tomatoes
  • Trail mix
  • Turnips
  • Vegetable juice
  • Walnuts
  • Wheat bran germ
  • Whole wheat flour
  • Wild rice (cooked)

* Note that these high-fiber foods are also goitrogenic, meaning that they promote thyroid enlargement and can potentially cause or aggravate hypothyroidism. Typically, the risk of goitrogenic foods is in overconsuming them, especially in raw form. Cooking or steaming typically eliminates most goitrogenic properties.

A Caution for Thyroid Patients

If you start a high-fiber diet and are taking thyroid hormone replacement medication, make sure that you have your thyroid blood test levels rechecked in six to eight weeks. Fiber can sometimes change the absorption of your medication, so it's important to recheck to see if you need to modify your dosage. 


Dahl WJ, Stewart ML. Position of the Academy of Nutrition and Dietetics: Health Implications of Dietary Fiber. Journal of the Academy of Nutrition and Dietetics. 2015;115(11):1861-1870. doi:10.1016/j.jand.2015.09.003.

Felker P, et. al. Concentrations of thiocyanate and goitrin in human plasma, their precursor concentrations in brassica vegetables, and associated potential risk for hypothyroidism." Nutr Rev. 2016 Apr;74(4):248-58. doi: 10.1093/nutrit/nuv110. PMID: 26946249.

Improving Your Health With Fiber. Cleveland Clinic.

Nutrition and Healthy Eating. Mayo Clinic.

Wald A. Patient Education: High-fiber diet (Beyond the Basics). UpToDate.

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