May 22, 2024

Medical Trend

Medical News and Medical Resources

Should patients with thyroid disease supplement Iodine?

Should patients with thyroid disease supplement Iodine?


Should patients with thyroid disease supplement iodine?Regarding the question about the diet of patients with thyroid disease, it is a false proposition to judge whether a food can be eaten without quantity. Some people say that iodine should be supplemented, and some people say that iodine cannot be supplemented! How should patients with thyroid disease eat?

Should patients with thyroid disease supplement Iodine?

Clinically, both the patient and the doctor should have been distressed by the attention to the diet of thyroid disease. Whether these foods can cure the disease as the rumors say, or if you eat too much, you can get sick. Eat as much as you want. To be small, it is really stupid and confused.

This article sorts out some common thyroid diseases and related diet studies, hoping to make us less detours in the treatment of thyroid diseases.



Hypothyroidism (hypothyroidism) is divided into clinical hypothyroidism and subclinical hypothyroidism. The causes of hypothyroidism include autoimmune damage, surgical removal of the thyroid gland, radioactive iodine destruction, external radiation, iodine deficiency or iodine excess, etc.

If the patient has hypothyroidism due to total removal or complete destruction of the thyroid gland, they will generally take levothyroxine (L-T4) for treatment. Many foods will affect the intestinal absorption of levothyroxine, but the consumption of iodized or uniodized salt has no significant effect on the thyroid.

However, it is recommended that patients with hypothyroidism can take the medicine before going to bed, because taking L-T4 for the treatment of hypothyroidism is effective and safe, helping to relieve symptoms and restore normal thyroid hormone levels.

If the patient’s thyroid lobes are removed or there is residual thyroid tissue, the iodine-containing diet can be carried out normally, including the consumption of iodized salt.

Generally, hypothyroidism caused by iodine deficiency often occurs in iodine-deficient areas, and eating iodized salt is the most effective method. The degree of hypothyroidism caused by excess iodine is relatively mild, and subclinical hypothyroidism is common. At this time, it is necessary to find the cause of excess iodine and limit iodine intake, such as avoiding drinking high-iodine water or eating too much iodine-rich food.



Patients with hyperthyroidism (hyperthyroidism) account for 1.3% of the total population, which is a fairly large group. The main cause of hyperthyroidism is toxic diffuse goiter (Graves disease). Serum thyroid stimulating hormone antibodies can induce or aggravate Graves disease. The trace elements iodine and selenium in the diet can regulate the content of these thyroid-related antibodies.

Therefore, clinically, patients with thyroid nodules should be reminded to control their daily iodine intake levels and review them in time to reduce the risk of hyperthyroidism induced by excessive iodine intake.


Thyroid nodules

Thyroid nodules are generally found through imaging examinations, and the malignant rate is 7%-15%. The clinic judges whether a needle biopsy is necessary based on the size of the nodule and the imaging characteristics. If it is highly suspected to be a malignant nodule, or a benign nodule that has compressed the neck, surgical resection of the thyroid can be performed; if the biopsy reveals a benign or non-suspect nodule, the patient is generally scheduled for regular ultrasound follow-up.


At this time, the patient would say: “Doctor, can I eat iodized salt and seafood like this…?”

Regarding the dietary taboos of patients with thyroid disease, the following will answer through some frequently asked food classifications.


Don’t be afraid of iodine-containing foods, iodine deficiency is not a good thing

Iodine is the closest friend of the thyroid gland. When iodine enters the human body, it will be firmly grasped by the thyroid gland and synthesize the thyroid hormone, the fuel of life. The relationship between iodine and thyroid disease is in a “U”-shaped curve. Excessive or lack of iodine will affect thyroid function.

Therefore, excessive iodine and iodine deficiency are not acceptable!

The World Health Organization (WHO) recommends that healthy adults (non-pregnant women) need to consume 150-200 micrograms of iodine per day, and women during pregnancy and lactation should ensure at least 250 micrograms of iodine per day. Hospitals generally determine the iodine content in the human body through urine iodine determination, and it is generally considered that the iodine content is between 100-200 mg/L as the appropriate state.

Regarding the dietary intake of iodine, according to clinical experience, a normal diet can maintain sufficient iodine intake. People with special dietary habits, such as vegetarians, are at greater risk of insufficient iodine intake, because vegetables are not rich in iodine. food.

In addition, a pill called “Iodine for Thyroid Health” is sold in pharmacies. The single dose of this medicine is hundreds of times the daily recommended iodine intake. Since excessive iodine supplementation can not only improve the condition of thyroid disease, but also affect thyroid function, it is generally not recommended for patients to buy and use this medicine and some health products that claim to be “good for the thyroid”: spirulina, kelp tablets and other nutrients. The American Thyroid Association recommends avoiding supplements containing >500μg/d of iodine.

In addition, seafood is also a major source of iodine for the human body, which is divided into three categories according to the iodine content:

  • High iodine content: algae such as kelp and seaweed;
  • Medium iodine content: shrimp, scallop;
  • Low iodine content: hairtail, salmon, small yellow croaker, etc.

So how should thyroid patients take iodine?

After treatment, patients with hyperthyroidism, if the thyroid function is not normal, or accompanied by goiter, excessive intake of iodine will make the condition worse, and at this time, “iodine” diet must be avoided;

If the thyroid function of the patient with hyperthyroidism is normal, and the thyroid gland is not significantly enlarged, if you want to eat seafood, you can choose small yellow croaker, hairtail, and cuttlefish with less iodine to eat. Once a week is acceptable, use non-iodized salt when cooking.

For those with simple thyroid nodules, it is best to selectively eat seafood after measuring their own iodine content.

Regarding Hashimoto’s thyroiditis, long-term high iodine diet can be induced, and it can occur in several generations of the same family due to genetic factors. It is recommended that children of patients with Hashimoto’s thyroiditis reduce their iodine intake and check thyroid function if necessary to prevent them in advance.

To sum up, patients with goiter and hyperthyroidism do not need to “sniff the iodine color”, and rationally evaluate the intake according to the condition.


Goiter: Which foods contain?

The pathogenic mechanism of goiter is that goiter is preferentially combined with iodine in the blood, resulting in insufficient iodine source for thyroxine synthesis, leading to compensatory hyperplasia of the thyroid gland. The most common foods that cause goiters are cruciferous vegetables and soy products.

▎ Cruciferous vegetables

Common cruciferous vegetables in life include broccoli, cabbage, radish, broccoli, kale, etc. These plants contain an antioxidant called glucosinolate, which is hydrolyzed in the human body to generate isothiocyanate Salt, thiocyanate is a goiter causing substance. But cruciferous vegetables are not useless. Glucosinolate hydrolyzate has anti-cancer properties and is beneficial to human health.

The results of current research suggest that long-term intake of large amounts of cruciferous vegetables may cause disorders of thyroid hormone production and lead to goiter, but there is no strict research to support consumption.

It is recommended to seriously consider the problem of goiter caused by cruciferous vegetables if the following situations occur:

Eating a large amount of cruciferous vegetables in a short period of time is equivalent to eating 2 catties of broccoli, radishes, cabbage, etc. per day;

You eat cruciferous vegetables at the same time: have a history of heavy smoking, or are in a low-iodine area and cannot eat seafood and iodized salt, or use flavonoid-rich fruits (apples, pears, grapes, oranges) at the same time.

Otherwise, patients with thyroid disease can properly consume cruciferous vegetables, especially those who often eat seafood and coastal areas, which can effectively reduce the stimulating effect of high iodine on the human thyroid.

Beans and soy products: the most overlooked thyroid diet

Soy products are common dishes in most southern regions, mainly including soy milk, tofu, soy sauce, tempeh and miso. Because it is common, patients have ignored the impact of soy products on thyroid function.

Most soy products contain isoflavones, which are inhibitors of thyroid peroxidase and reduce the synthesis of thyroid hormone. Some researchers have suggested that daily dietary intake of beans or soy products will increase the risk of hypothyroidism. You may need to take a larger dose of thyroxine after using beans.

Studies have shown that in areas where iodine is sufficient, the serum thyroid function of people with normal thyroid function after consuming soy products is not abnormal. Special attention is needed if soy formula milk powder is consumed in children with congenital hypothyroidism, the dose of levothyroxine should be appropriately increased , To ensure that children’s thyroxine needs are met.

Although it is necessary to pay attention to the intake of soy products, clinical studies do not have sufficient evidence to require adult hypothyroid patients to fast soy products. It is reasonable for patients to eat soy products normally (but don’t eat too much!).

Other trace elements:


Selenium is an important trace element that affects the metabolism of thyroid hormones. It is rich in seafood and animal organs. It can also meet the intake of selenium by eating bread, grains, meat, poultry, fish and eggs. The health industry standard recommendations of the People’s Republic of China issued in 2017: The average daily selenium requirement for adults is 50μg, and the maximum intake is 400μg.

Although selenium poisoning is not common clinically, the symptoms include nausea; nail discoloration, brittleness, and shedding; hair loss; fatigue; irritability and bad breath (often called garlic bad breath).

Some studies show:

Appropriate selenium supplementation improves the condition of patients with autoimmune thyroid diseases; the increased risk of goiters and thyroid nodules in European women may be related to selenium deficiency; in areas with severe selenium supply, daily intake of selenium may be allowed Up to 100μg, but current research does not support routine selenium supplementation in patients for the treatment of Graves’ disease, reducing serum thyroid antibody levels, or maintaining normal thyroid function.

However, in clinical practice, patients are generally not required to supplement selenium simply for the treatment of thyroid diseases. However, the European Thyroid Association and the European Group of Graves ophthalmopathy recommend that patients with mild Graves ophthalmopathy be supplemented with selenium for a period of 6 months to improve the disease. The quality of life during and after the ophthalmopathy is cured.

▎Zinc, copper and magnesium

At present, the role of zinc, copper and magnesium in the synthesis and metabolism of thyroxine is not clear. A meta-analysis of 8 studies suggests that there is a correlation between selenium, copper and magnesium and thyroid cancer. The results of the National Health and Nutrition Survey (2011-2012) in the United States suggest that the correlation between zinc, copper and selenium and human serum free or total thyroxine levels is not consistent. Based on the existing research evidence, we do not recommend supplementing zinc, copper, and magnesium simply to improve thyroid function.

Regarding the question about dietary attention of patients with thyroid disease, it is a false proposition to judge whether a food can be eaten or not by leaving the quantity. The correct dietary attention should be based on understanding the basis of the disease, using intake and related clinical indicators to determine. I hope this article can help you avoid the minefield of “thyroid disease diet” and achieve a balanced diet and a healthy life


(source:chinanet, reference only)

Disclaimer of