NUTRITION

In the Face of Controversy, Should We Intake Iodized Salt?

As the incidence of thyroid diseases increases in recent years, people begin to have doubts on the intake of iodized salt. And the emergence of bamboo salt, lake salt, Himalayan rose salt and other new salts also provokes people to contemplate on the choice of edible salt and remain unpersuaded of the use of iodized salt.

Perception of Iodized Salt Needs Correction

Iodine is one of the essential microelements for human body. The popularization and the use of iodized salt in the early stage have played a key role in curbing iodine deficiency in China ^[1]. However, the excessive intake of iodine in recent years cannot be ignored. Therefore, in today’s environment, it is important to accurately see and study the role of iodized salt. The positive effect of iodized salt is to replenish iodine, to ensure that the human body will not suffer from goiter, cretinism and many other problems because of iodine deficiency ^[2]; the negative effect of iodized salt is that it may cause iodine excess and cause harm to thyroid function, intelligence, sexual functions, etc. There is no absolute "right" or "wrong" for taking iodized salt, but only "appropriate" and "inappropriate". Thus people should have unbiased concept about iodized salt.

Analysis of Hidden Danger of "Emerging Salt"

Under the controversy of iodized salt, some people have begun to favor bamboo salt, lake salt, rose salt and other "emerging salts", but the study confirmed that these salts also have many hazards to human body.

Bamboo salt is made by baking natural sea salt in fresh bamboo at high temperature for many times. In the process of bamboo salt burning, the fragrance of bamboo will seep into the salt, but the sodium ion in the salt may be relatively high that hypertensive patients should be cautious when choosing bamboo salt. Himalayan rose salt is a rock salt with attractive pink color, containing 84 elements, 17 of which are unnecessary for human body, including arsenic, lead, aluminum, cadmium, mercury, rare earths and others, and the intake of sodium, phosphorus needs to be controlled ^[3]. Lake salt is a salt collected directly from a salt lake or field. It mainly contains sodium chloride, mixed with potassium chloride, magnesium chloride, calcium chloride, magnesium sulfate, calcium sulfate and iron, so patients with high blood pressure, kidney disease, and edema should not consume lake salt.

Refusal of Iodized Salt should Not Be a Common Phenomenon

In general, whether to choose iodized salt depends on the existence of high iodine in the area. In addition to food, medicine and other factors, high iodine content in water is also one of the main reasons for iodine excess. Studies have confirmed that residents in high iodine areas can still meet their iodine supply needs without consuming iodized salt ^[4]. However, it should be noted that there are only 30 million people in China living in areas with high iodine levels. According to a 2012 survey by the Ministry of Health, China’s high water iodine areas have been reduced from 130 counties in 12 provinces to 735 townships in 109 counties in 9 provinces in Tianjin, Hebei, Shanxi, Inner Mongolia, Jiangsu, Anhui, Shandong and Henan.

Therefore, unlike people living in high water iodine areas who do not need to consume iodized salt, residents living in other areas still need iodized salt to meet their iodine needs.

Choose a Scientific Iodine Supplement Program

According to the consensus of the World Health Organization (WHO) and the Chinese Nutrition Association (CNA), 150 μg of iodine per day can meet the needs of the body for adults. 200 μg/d iodine intake during pregnancy and lactation is suitable for adults, while the iodine intake for minors decreases with age. According to the evaluation criteria of dietary iodine intake in the Guide to Iodine Supplementation for Chinese Residents:

Dietary iodine intake = ∑ (intake of all kinds of food × iodine content of all kinds of food) + (quantity of drinking water + quantity of cooking food) × water iodine content + intake of salt × iodine content of salt × (1-cooking loss rate). The loss rate of iodized salt defined by WHO is 20%.

For example, when an adult consumes 5g of iodized salt a day, and if the iodine content in the salt is 25mg/kg, about 20% of the iodine will be lost after cooking, and then the iodine intake through iodized salt is about 100μg. The amount of iodine available in drinking water is 10μg/day, and 25-50μg of iodine can be supplemented by food per day, just enough to meet the recommended intake of iodine.

For iodine supplement during pregnancy, it is necessary to choose the appropriate iodine program according to the urine iodine test during the pre-pregnancy and first three months of pregnancy. Patients with hyperthyroidism, thyroiditis (Hashimoto’s disease), thyrophyma, thyroid dysfunction, other thyroid diseases and pregnant and lactating women with thyroid diseases, as well as those living in areas with high iodine, as mentioned above, are required to determine the iodine intake plan based on the test.

In conclusion, iodized salt is the most commonly used, safest and most effective method recommended by the World Health Organization (WHO) to supplement iodized salt. Consuming iodized salt is still an important way for people to supplement iodized elements. Avoiding consuming iodized salt without evaluating it would be irresponsible to your body.