How High-Fiber Foods Can Benefit Your Thyroid

A high-fiber diet can aid digestion and lower your risk for other conditions

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Most of the foods you eat, including carbohydrates, fats, and proteins, are broken down and absorbed by your body. The exception is dietary fiber, sometimes called “roughage,” which passes through your body virtually untouched.

When you have a thyroid condition, a diet that's high in fiber can be particularly beneficial to you by helping with weight loss and easing chronic constipation, a common effect of hypothyroidism (underactive thyroid), or diarrhea, a common outcome of hyperthyroidism (overactive thyroid).

benefits of fiber for thyroid disease
 Illustration by Emily Roberts, Verywell

Fiber's Benefits for Thyroid Complications

Fiber is an important part of anyone's diet, but there are many aspects of a high-fiber diet that are of particular importance and benefit to those with thyroid disease.

Lowers the Risk of Heart Disease

Studies show that when you eat a high-fiber diet, you lower your risk of coronary artery disease and heart attack by as much as 40% to 50%. Research has also found that your risk of heart disease may be decreased by 9% for every 7 grams you increase your daily fiber intake.

Since thyroid disease puts you at a higher risk for heart disease, including coronary artery disease, stroke, and heart attack, this benefit is particularly meaningful.

In addition, soluble fiber in particular may help lower low-density lipoprotein (LDL), the "bad" cholesterol. It also can reduce heart inflammation and blood pressure levels. This benefit may also contribute to lowering your risk of heart disease.

Helps With Weight Management

Weight gain, difficulty losing weight, and trouble maintaining a healthy weight can be a challenge when you have hypothyroidism. The more fiber you get in your daily diet, the lower your risk of obesity.

This is likely because fiber makes you feel full, helping you eat less. Fewer calories each day can eventually lead to weight loss over time. 

Aids Your Digestive System

Dietary fiber helps control the digestion of other foods, a helpful effect since digestion can be slow when you have hypothyroidism.

A high-fiber diet can help alleviate hard stools and constipation—common complaints of people with hypothyroidism. This, in turn, may reduce the risk and severity of hemorrhoids, a common outcome of chronic constipation.

If you have hyperthyroidism, you may have issues with diarrhea, so upping your fiber intake can help regulate your bowel movements as well.

Helps Control Blood Sugar Levels

People with diabetes on a high-fiber diet have a slower absorption of sugar, promoting better glucose levels. Eating a high-fiber diet may also decrease your chances of developing type 2 diabetes, a risk that's higher when you have thyroid disease.

Reduces the Risk of Diverticulosis

If you have hypothyroidism, you may be more likely to develop diverticulosis, an inflammation or infection of the small pouches lining your intestine. Insoluble fiber has been shown to reduce this risk. If you already have diverticulosis or inflammatory bowel disease, be aware that some people have worse symptoms with more fiber, while others have fewer symptoms.

Fiber-Rich Foods

The Academy of Nutrition and Dietetics recommends that 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; once you're over the age of 50, women should get 21 grams and men should get 30 grams a day.

Having thyroid disease doesn't necessarily mean you need more fiber than any other individual. Ensuring that you get the recommended amount, however, may be especially important for you.

You can look up the amount of fiber and any other nutrient in many foods on the United States Department of Agriculture's (USDA) FoodData Central.

Soluble Fiber

Soluble fiber 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. You can find soluble fiber in these foods:

  • Apples, with skin
  • Barley
  • Beans
  • Carrots
  • Citrus fruits
  • Corn
  • Hazelnuts
  • Jicama
  • Mixed vegetables (frozen)
  • Oats
  • Okra, cooked
  • Onion (white, yellow, red; cooked)
  • Parsnips
  • Pears
  • Prunes
  • Peas, cooked
  • Soy flour*
  • Yams

Insoluble Fiber

Insoluble fiber makes your stool softer and easier to pass, helping to prevent constipation and keeping the pH level in your intestinal tract at an optimum level. The foods that are highest in insoluble fiber include:

  • Almonds*
  • Apple with skin
  • Baking chocolate
  • Barley, cooked
  • Barley flour
  • 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
  • Flaxseed
  • 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, cooked
  • Peanuts*
  • Pears
  • Peas
  • Pine nuts
  • Pineapple
  • Pistachios
  • Potatoes
  • Prunes
  • Pumpkin seeds
  • Pumpkin puree
  • Quinoa
  • Raisins
  • Raspberries
  • Rhubarb
  • Rice (brown, cooked)
  • Rutabaga
  • Rye flour
  • 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 high in goitrogens, substances that can affect thyroid function.

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7 Essential Facts About Goitrogens and Diet

Starting a High-Fiber Diet

After considering all the benefits of a high-fiber diet, you may be eager to get started. There are some important considerations to keep in mind before you begin.

  • Start slow. Don't jump from 10 grams to 30 grams of fiber in one day. You need to give your digestive system time to adjust because adding too much fiber too quickly can cause discomfort.
  • Be aware of grain sensitivities. Try to incorporate as many fiber-rich foods as you can into your daily menu. If grains, particularly wheat, seem to be an issue for you, ask your healthcare provider to test you for celiac disease; your risk of having it is higher when you have autoimmune thyroid disease (Hashimoto's thyroiditis or Graves' disease). It's also possible to have a gluten or other grain sensitivity that requires that you limit or eliminate the offending grain from your diet.
  • Focus on high-fiber foods beyond grains. Though high-fiber grains, bread, and pasta give you fiber, they can also derail your weight loss efforts if you eat too much. When you use fiber to help with weight loss, it's best to concentrate on the highest-fiber vegetables, legumes, beans, nuts, seeds, and fruits.
  • Drink more water. It's a good idea to increase your intake of water to help avoid bloating, cramping, pain, and gas, which can occur as you eat more fiber.
  • Don't overdo it. Getting too much fiber can also uncomfortable digestive symptoms, so be sure not to go overboard in your efforts to up your fiber intake. Aim for the daily recommended amount.
  • Consider fiber supplements. It can take a great deal of food to reach the recommended fiber levels. To get to the optimal daily intake, you may need to add a fiber supplement to the mix, though it's best to get your fiber from food if you can.

Fiber Supplements

A number of different fiber supplements are available over the counter. Two of the most popular types include:

  • Psyllium: Studies have found that taking psyllium before you eat may help you eat less and feel full more quickly during a meal and keep you feeling satisfied for longer afterward. Psyllium husk is found in commercial products like Metamucil. It's inexpensive and, when taken in capsule form, it's portable and easy to take.
  • Guar gum: A high-fiber supplement that's found in a popular fiber powder product called Benefiber, guar gum dissolves completely into drinks like juice, water, or smoothies without adding grit, bulk, or taste (the same cannot be said for other fibers, including psyllium).

Fiber supplements can cause gas, cramping, bloating, or diarrhea in some people, especially when you first start taking them. As with high-fiber foods, increase your dose slowly and drink plenty of water.

Supplements can also interfere with the absorption of certain medications, so talk to your healthcare provider or pharmacist before you start taking one.

Medication Interactions

Be sure that you're taking your thyroid medicine at least an hour before eating or taking any fiber supplement. Fiber can affect medication absorption and significantly change your thyroid drug dosage requirements.

Have your thyroid function tested six to eight weeks after starting a high-fiber diet to make sure you don't need a dosage change.

10 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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Mary Shomon

By Mary Shomon
Mary Shomon is a writer and hormonal health and thyroid advocate. She is the author of "The Thyroid Diet Revolution."