Children who are told to eat their fruits and vegetables rarely understand the significance and importance of the advice and the fact that such foods can play a key role in the health of one of the most important tissues in the body — the thyroid gland.
While you probably won't be able to control thyroid disease through fruits and vegetables alone, choosing the best food for thyroid patients, along with the proper treatment, may help you manage your condition and improve your quality of life.
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The Importance of Your Thyroid
The thyroid gland is a small, butterfly-shaped gland that lies in the middle of the lower neck. Even though the thyroid gland is small, it plays a big role in your body. The thyroid gland uses a mineral called iodine to produce three major hormones:
- Triiodothyronine, or T3
- Tetraiodothyronine, or thyroxine or T4
These hormones help control your metabolism, playing major roles in growth, development, weight management and the regulation of your body temperature. The thyroid gland relies on messages from another gland in your brain, called the pituitary gland, about how much of each hormone to make.
When the pituitary gland senses that you need more thyroid hormones, it sends out another hormone called TSH, or thyroid-stimulating hormone, to tell the thyroid gland to make more. When it senses that you need less, it scales back on the amount of TSH it pumps out to tell your thyroid gland that it can stop producing and sending out hormones for a little while.
The Prevalence of Thyroid Disease
But sometimes, these messages get skewed and thyroid function, and the amount of hormones you have in your body, become imbalanced. This can happen due to inflammation of the thyroid, autoimmune disease, too much or too little iodine or growths on the thyroid gland called thyroid nodules, although health experts aren't totally clear why these things happen.
According to the American Thyroid Association, 12 percent of people in the United States will develop a thyroid condition at some point in their lifetime. Approximately 20 million Americans already have some form of thyroid disease and 60 percent of those affected don't even know it. Women are five to eight times more likely to develop some type of thyroid disease.
There are two major classes of thyroid disease:
- Hypothyroidism: a condition in which the thyroid gland doesn't produce enough thyroid hormones.
- Hyperthyroidism: a condition in which the thyroid gland produces too much thyroid hormones.
The Role of Selenium
Because the function of your thyroid is directly connected to certain nutrients, eating different vegetables and fruits for thyroid health may help prevent thyroid disease or help you manage it if you already have it. Selenium is an essential trace mineral that plays major roles in your brain health, immune system and fertility. Most of the selenium in your body is found in your thyroid gland, and, because of this, the mineral also keeps your thyroid functioning normally.
One review, published in the journal Current Opinion in Endocrinology, Diabetes and Obesity in October 2015, reported that studies have shown that increasing intake of selenium in those with autoimmune thyroiditis and Graves' disease may improve symptoms and reduce the clinical markers of thyroid disease, like thyroid antibodies.
Sources of Selenium
Most of the selenium content in fruits and vegetables comes from the soil they're grown in, so amounts can vary, but some fruits and vegetables that contain selenium and that are good for the thyroid include spinach, green peas, bananas and baked potatoes.
Although fruits and vegetables contain some selenium, the richest source of the mineral is Brazil nuts, which contain 777 percent of the amount you need for an entire day in just six to eight nuts. In addition to upping your intake of selenium-rich fruits and vegetables, it may be a good idea to eat a couple Brazil nuts every day, too.
But be careful not eat too much. If you regularly go over your selenium needs, you may develop a selenium toxicity, which is characterized by hair loss and a metallic taste in the mouth. Make sure you get enough of the mineral, but don't overdo it.
Vitamin A and Your Thyroid
Vitamin A is another nutrient that's been shown to play critical roles in your thyroid health. According to an August 2012 report published in the Journal of the American College of Nutrition, vitamin A helps regulate the metabolism of thyroid hormones by shutting off the production and release of TSH, when necessary. The report notes that women who were given vitamin A experienced lower TSH levels in their blood.
To keep your thyroid functioning normal, it's important to meet your daily vitamin A needs, which are 700 micrograms per day for women and 900 micrograms daily for men. Fruits and vegetables that are rich in vitamin A include:
- Sweet potato
- Red peppers
- Dried apricots
- Summer squash
Produce and Thyroid Cancer
Because fruits and vegetables are rich in vitamins, minerals and various phytochemicals, a high intake is associated with a reduced cancer risk in general; but the types of fruits and vegetables you eat may also play a role in protecting you against thyroid cancer, specifically.
A study published in Clinical Nutrition Research in July 2014 reported a connection between lemons and tomatoes and thyroid cancer. Researchers found that both lemons and tomatoes were associated with a decreased risk of thyroid cancer.
Another study, published in the British Journal of Nutrition in January 2013 reported a connection between tangerines and persimmons and a reduced risk of thyroid cancer. The same study found that a high intake of raw vegetables was inversely associated with both benign and malignant thyroid cancers and that eating a lot of vegetables may help prevent early-stage thyroid cancer.
Avoid Goitrogenic Foods
On the other hand, there are also some fruits and vegetables, as well as other categories of foods, that you should avoid, or limit, when you have thyroid disease. These foods are classified as "goitrogenic foods." When they're broken down, goitrogenic foods release a compound called goitrin, which can block the synthesis of thyroid hormones. If you have thyroid disease, you may need to avoid or limit goitrogenic vegetables, which include:
- Cassava root
- Mustard greens
However, a January 2016 report in the Journal of Clinical and Diagnostic Research notes that soaking, washing and cooking can reduce the amount of active goitrin, making these foods easier on the body, even if you have thyroid disease. A July 2012 issue of Today's Dietitian adds to this by saying that goitrogenic vegetables are typically only a problem when combined with iodine deficiency.
Best Food for Thyroid Patients
There are other foods, aside from some specific fruits and vegetables, that are good for your thyroid, though. Following an overall healthy diet will help keep your thyroid healthy by supplying all of the nutrients it needs to function optimally.
Harvard Health Publishing recommends eating a variety of fruits and vegetables as well as nuts, seeds and lean proteins like fish and beans. In addition to essential vitamins and minerals, fruits, vegetables and beans will also provide you with fiber, which keeps your digestion running smoothly.
But it's not just about what you should eat; it's also about what you should avoid. Limit simple carbohydrates, like sugar and white flour, which can negatively affect the thyroid, as well as trans fats, which are often found in processed foods and commercially-baked foods.
- Journal of Clinical and Diagnostic Research: "Various Possible Toxicants Involved in Thyroid Dysfunction: A Review"
- Cleveland Clinic: "Thyroid Disease"
- American Thyroid Association: "General Information/Press Room"
- Today's Dietitian: "Thyroid Disease and Diet — Nutrition Plays a Part in Maintaining Thyroid Health"
- British Journal of Nutrition: "The Effect of Raw Vegetable and Fruit Intake on Thyroid Cancer Risk Among Women: A Case-Control Study in South Korea"
- Harvard Health Publishing: "Healthy Eating for a Healthy Thyroid"
- Current Opinion in Endocrinology, Diabetes and Obesity: "Selenium and the Thyroid"
- Clinical Nutrition Research: "Dietary Factors and the Risk of Thyroid Cancer: A Review"
- National Institutes of Health Office of Dietary Supplements: "Selenium"
- National Institutes of Health Office of Dietary Supplements: "Vitamin A"
- Journal of the American College of Nutrition: "The Effect of Vitamin A Supplementation on Thyroid Function in Premenopausal Women"