Truth, do you want iodized salt?

Iodine is an essential micronutrient for human body, It is also a controversial topic in recent years. China is one of the countries with the most serious iodine deficiency in the world. The [macroneck disease] caused by iodine deficiency was recorded in the Warring States Period of China. In addition, Iodine deficiency can also cause childhood dementia, It may even cause brain development disorders in children. Fortunately, At present, [iodine deficiency disease] in our country has been eliminated on the whole, In the process, The policy of adding iodized salt to salt is the most important one. In 2009, Some media began to hype the topic of iodized salt [disease], Linking the rise in thyroid cancer incidence to iodized salt, At once, the policy of iodizing salt was pushed to the forefront. At that time, Iodized salt has become widely condemned, Non-iodized salt, which should have been used by a few people, has become a hot topic. However, the tables have turned, In 11 years, the earthquake in Japan to the east slipped the status of iodized salt from one extreme to the other. Many places have seen the phenomenon of crazy robbery of iodized salt, bringing salt for themselves has become a sign of local tyrants. In fact, whether iodized salt causes cancer or iodized salt protects against radiation is just a myth based on false speculation.

The diet structure varies from place to place in the whole country. Is there any suspicion of a one-size-fits-all iodine supplement in the whole country?

Some people think that people in coastal areas have taken enough iodine in the process of eating seafood. The continued addition of iodine to salt will lead to excess iodine intake in coastal areas. At the same time, some people also cited epidemiological survey data on cancer. It is believed that the rising incidence of thyroid cancer in China is also related to the addition of iodine to salt. But in fact, These speculations have been refuted by epidemiological findings. An epidemiological observation was quoted in the National Risk Assessment of Salt Iodization and Iodine Nutrition Status of Residents in China released in 2010. Among the residents of Shanghai, Liaoning, Zhejiang and Fujian, Except for children aged 8-10 years old, the proportion of people with insufficient iodine intake (23.5% ~ 29.0%) is significantly higher than that with excessive iodine intake (11.1% ~ 14.2%). The reason is also very simple. Although we have been promoting that seafood contains more iodine, the contribution rate of laver and kelp in dietary iodine intake is actually only 1.6% to 3.0%, and these high iodine foods are not eaten every day at all!

Is iodized salt carcinogenic?

And there is also insufficient evidence that iodized salt causes cancer. With people’s attention to their own health and the development of ultrasound technology, More and more thyroid nodules less than 1 cm are screened out, This also creates the illusion that thyroid cancer is increasing. One possible truth is that With so many early thyroid cancers, But in the past, the technology was not enough, the consciousness was not enough, It didn’t come out. Meanwhile, Researchers in Switzerland also observed that the incidence of thyroid tumors gradually decreased rather than increased after salt iodization. Similarly, The results of the case-control study also showed that thyroid cancer was not related to the dietary iodine intake of the population. In fact, At present, the research on the harm of iodine excess to human body is mostly based on the research results of animal models. Whether the results can be directly applied to human body is controversial, However, the observation results of the population suggest that long-term iodine excess may cause hypothyroidism or goiter in some sensitive people. However, the harm caused by these changes to the human body is far less than the mental decline and growth retardation caused by iodine deficiency. Therefore, it is more reliable for ordinary people to continue to eat iodized salt. Unless you are a diagnosed thyroid disease patient.

Iodized salt against radiation?

The 2011 magnitude 9 earthquake in Japan caused a nuclear leak at the Fukushima nuclear power plant. Although the polluted sea water had not yet drifted to China at that time, However, we have seen a large number of people snapping up iodized salt here. The logic of snapping up iodized salt is a bit twisted: Before exposure to radioactive iodine, a large amount of iodine is used to saturate the iodine in the body, thus preventing radioactive iodine from depositing in the thyroid gland, thus avoiding radiation damage. Regardless of whether this method of taking iodine to avoid radiation is really effective or not, it is quite impossible to achieve iodine saturation by using iodized salt alone.

At present, the upper limit of iodine content in the national iodized salt standard is 30mg/kg. Even if the influence of iodine volatilization during storage and transportation is ignored, to reach the content of iodine tablets (usually 100 ~ 130mg) means that everyone needs to take more than 4kg of iodized salt every day to reach such iodine content. In other words, before nuclear radiation killed you, you were already salty.

In the final analysis, iodized salt still needs to be eaten, as long as it is eaten reasonably.