Iodine is an important raw material for thyroid hormone synthesis and is closely related to thyroid function.
Normally, our total body iodine content is about 20 to 50 mg, with an average of 30 mg, of which the thyroid contains 8 to 10 mg. We usually eat 100-200 micrograms of iodine per day, of which 1/3 goes to the thyroid. Once you get below 50 micrograms of iodine a day, you cannot ensure proper synthesis of thyroid hormones.
In the early years, there was an epidemic of endemic goiter (commonly known as “big neck disease”) in many areas due to dietary iodine deficiency. The iodized salt policy has helped to control this disease.
In recent years, thyroid cancer has become more common, so some people wonder, “Is it too much iodized salt? The company’s main goal is to provide the best possible service to its customers. Here’s a breakdown.
Can eating iodized salt “cause” thyroid cancer?
Can you get thyroid cancer from eating iodized salt?
There is no direct evidence linking iodine intake to the development of thyroid cancer.
Some people suspect a link between the development of thyroid cancer and iodized salt based on the temporal synchronization of the two: salt iodization has been introduced in China over the last 30 years, and the incidence of thyroid cancer has increased each year over the same period. However, this is clearly not enough to establish a causal relationship between the two.
At the same time, this is also a 30-year period in which diagnostic techniques such as ultrasound have continued to develop and physical examinations of the population have become increasingly common, with more and more thyroid cancers being detected early, which may be a major reason for the increased incidence figures.
In fact, looking around the world, the incidence of thyroid cancer has increased in recent decades in countries where salt iodization is recommended or not.
Overall, there is no evidence that salt iodization is a direct cause of thyroid cancer, and more research remains to be done on the exact relationship between the two.
Should I still eat iodized salt?
Iodine is an essential micronutrient, and when iodine intake is insufficient, thyroid hormone synthesis is inadequate, affecting the growth and intelligence of children and adolescents. The first thing you need to do is to take a look at the results.
Iodine deficiency is severe in most parts of the country, and if you live in an iodine-deficient area, it is necessary to supplement with iodized salt and moderate amounts of seafood.
If you live in a coastal area where the diet is already rich in seafood, iodized salt can be eaten in moderation and less, which means paying attention to a low iodine diet and eating less iodine-rich foods such as seaweed and nori. It is important to note that some residents, who live in coastal areas but do not often eat iodine-rich foods, also need to get enough iodine from iodized salt.
There are also areas with high levels of iodine in groundwater (over 150 µg/L). People in these areas should consume uniodized salt. However, if the water is changed so that the iodine level drops, it is still important to consume iodized salt.
In general, people in China’s big cities are not iodine deficient, but a little more iodine does not affect their health, so as long as doctors do not explicitly recommend a low-iodine diet, there is no need to get hung up on “iodine”; a balanced diet, relaxation, and a combination of work and rest are more beneficial in preventing thyroid cancer.
Co-written by Dr. Tingting Zhang, Cancer Hospital, Fudan University