Health Science | Protect thyroid health and master "iodine" knowledge

Iodine is an essential micronutrient for promoting human metabolism and growth and development, and is an important raw material for synthesizing thyroid hormones. Humans mainly obtain iodine from drinking water and food. Under normal circumstances, 80% to 90% of the iodine in the human body comes from food, 10% to 20% from drinking water, and less than 5% from air. After being absorbed in the small intestine, iodine in food reaches the thyroid gland through the bloodstream. The iodine content in the thyroid gland accounts for 90% of the total iodine content in the body. The physiological effect of iodine on the human body is achieved through thyroid hormones. Thyroid hormones participate in metabolism, maintain the normal functions of almost all organs, and promote the growth and development of the brain and bones. Therefore, the thyroid gland is also called the "engine of the human body", and iodine has the reputation of being the "human intelligence element". 80% of human intellectual impairment is caused by iodine deficiency. Iodine deficiency disease is a general term for a series of diseases caused by insufficient iodine intake by the human body due to iodine deficiency in the natural environment. Iodine deficiency can cause goiter, abnormal intellectual development, and reproductive system effects. Humans lack iodine at different developmental stages, and the corresponding manifestations are also different. Even mild iodine deficiency in the fetus and childhood can cause varying degrees of intellectual impairment, and it is always irreversible. In severe cases, it can lead to short stature and low intelligence in the fetus, which is called "cretinism". The child's brain development begins when the mother is pregnant. The fetal period and infant period (1 to 3 years old) are critical periods for the child's brain development, because all the iodine needed in the fetal period comes from the mother. Therefore, insufficient iodine nutrition in the mother will cause iodine deficiency in the fetus, and severe iodine deficiency will cause fetal miscarriage, premature birth, stillbirth and congenital malformations. Pregnant women are a susceptible group for iodine nutrition. The incidence of iodine deficiency in pregnant women in my country is as high as 48.2%. The demand for iodine in pregnant and lactating women is significantly higher than that of the general population. Both iodine deficiency and iodine excess will affect thyroid function, leading to adverse outcomes of pregnancy and abnormal intellectual development of offspring. Iodine deficiency in adults can cause hypothyroidism, fatigue, lack of concentration, edema, decreased work efficiency, and a slower heart rate.

Iodine supplementation can not only treat iodine deficiency, but also is a necessary measure to reduce the incidence of various thyroid diseases. The simplest, safest and most effective way to prevent it is to eat iodized salt. Research from Professor Teng Weiping's team at my country Medical University has confirmed that the iodine nutrition of Chinese residents is already iodine-sufficient, and the current iodine intake dose is reasonable and safe. This dose can not only effectively prevent and treat iodine deficiency, but also avoid the negative effects of excessive intake. The results of the study showed that the incidence of the main thyroid diseases in my country: clinical hyperthyroidism, subclinical hyperthyroidism, clinical hypothyroidism, and goiter has decreased significantly. There was no significant change in autoimmune thyroiditis specific to thyroid antibodies, but the mechanism was unclear. Although the incidence of thyroid nodules showed a significant upward trend, this increase was not found to be related to iodine intake. Instead, it was found that increased iodine intake was a protective factor for thyroid nodules. At present, the international thyroid community generally believes that the main reason for the increase in the incidence of thyroid nodules is the increase in the probability of B-ultrasound screening of the thyroid and the improvement of the resolution of B-ultrasound equipment.

For the general population, as long as they eat qualified iodized salt, they can ensure iodine nutrition, and they do not need to eat any iodine-containing health products or iodine-fortified foods. Even in coastal cities, they should eat iodized salt and do not choose iodine-free salt. For pregnant women, in the first three months of pregnancy, during pregnancy and lactation, in addition to the normal intake of qualified iodized salt, they should also appropriately increase the intake of iodine-rich seafood (kelp, seaweed, etc.) to ensure iodine reserves.

For patients with thyroid diseases, they should choose low-iodine, adequate iodine, or iodine-free diets in a targeted manner and follow the doctor's instructions.

Health reminder:

In daily life, you should buy iodized salt as you eat it, and it is best to buy it in regular supermarkets and stores. Pay attention to the label and shelf life of qualified iodized salt, especially to see if it meets the salt content standards of the province. Do not have too much or too little iodine. Adhere to scientific iodine supplementation and correctly use qualified iodized salt to prevent the resurgence of iodine deficiency and avoid the harm of excessive iodine, and protect your thyroid health.