From July 2065438 to July 2007, the Ministry of Health and Welfare of the Food and Drug Administration issued the Scope and Specification for the Use of Food Additives. One of the major revisions was to raise the standard of iodine concentration in table salt from the previous 12 ~ 20mg/kg to 20 ~ 33mg/kg. Why does * * * have to be modified like this? What's wrong with iodine nutrition in China?
Half of China people suffer from iodine malnutrition.
In fact, as early as May of 20 15, the national health agency issued the "Analysis Plan of Urine Iodine Concentration in the National Survey of Nutrition and Health Status Change 20 13", and found that the median urine iodine concentration of people over 6 years old in China was 96 μ g/L. There are 5 1.9% people in China whose urinary iodine concentration is lower than the lower limit of 100 μ g/L recommended by the World Health Organization. Among them, 19 ~ 44 years old female iodine deficiency accounted for 39.5%.
Chen Shiting, a nutritionist at Kangning Hospital, said that in countries with iodine deficiency, it is usually because people can't get enough iodine from natural diet, and they have to rely on extra iodine added to food to provide it. However, early people in Taiwan Province Province seldom lacked iodine. Why do people in Taiwan Province Province start to lack iodine now?
The reason is that Taiwan Province Province monopolized salt products in the early stage and fully implemented the policy of iodizing salt. However, after the free trade of salt products in 1993, the iodine content of domestic salt and imported salt in the market, especially mineral salts such as rose salt, natural sea salt and rock salt, is only about 20 micrograms per kilogram. If everyone consumes 65,438+00g of salt every day, they can only get 2 micrograms of iodine, and if these people contain iodine.
Iodine is closely related to metabolism and development.
Why is iodine so important to human body? Wang Lvkai, an attending physician in the Department of Family Medicine, Changhua Christian Hospital, said that iodine is an essential nutrient to maintain thyroid function, mainly synthesizing thyroxine T3 and T4, and its role in the body is to regulate gene expression, metabolism and development; In the metabolic part, thyroxine will directly affect the oxygen consumption and metabolic rate of tissues, including changing the respiratory efficiency of mitochondria, increasing energy consumption and speeding up the heartbeat.
In the part of growth and development, the fetus needs iodine nutrition when it is in the mother's womb. It was found that there were thyroid receptors in fetal brain within 10 weeks, which would affect the development of nerve cells and spine, and also affect the development of bones and trunk until 2 years old.
Especially the nutrition of pregnant women, due to the influence of their own hormones, urine will excrete more iodine, coupled with the needs of the fetus, making pregnant women more prone to iodine deficiency than the average person. As long as pregnant women are slightly short of iodine, it may cause goiter of the mother and fetus. If iodine deficiency is serious, it may also lead to fetal nerve development and intellectual defects, and even lead to abortion in severe cases.
Physiological demand of iodine
Chen Shiting said that iodine is the only nutrient in the human body that is directly proportional to calories, and it needs 5 micrograms per 100 calories.
Iodine nutrition. In the seventh edition of the Revised Reference Intake of Dietary Nutrients for China Residents, it is suggested that the daily requirement of adults over 9 years old should be 140 micrograms; Pregnant women need to add 60 micrograms and *** 200 micrograms; For lactating women, it is necessary to add 1 10 microgram and *** 250 microgram.
Iodine deficiency leads to five health crises
Iodine is an essential nutrient to maintain thyroid function, which can promote metabolism and tissue growth. When it is deficient, it is easy to feel tired, afraid of cold, goiter and mental disorder, and it is easy to get fat because of slow metabolism.
Wang Lvkai said that if children and adolescents lack iodine, they will have problems such as mental retardation and short stature. Adults will cause mental retardation, such as poor memory, mental retardation and slow response, which will increase the risk of cardiovascular diseases. Long-term deficiency of women may affect endocrine balance, resulting in menstrual disorder and infertility; Among them, the fetus and newborn whose nervous system is still developing have the greatest influence.
1. Affect children's cognitive development
The most famous disease of iodine deficiency is dementia. Chen Shiting explained that this is because the mother lacks iodine during pregnancy and cannot synthesize enough thyroxine for fetal development, which leads to muscle weakness, congenital malformation, skin thickening, skeletal development stagnation, mental retardation and cognitive impairment after birth, which is called "dementia". In addition, iodine deficiency may also lead to miscarriage and stillbirth of pregnant women.
Among them, it has the greatest influence on the development of nervous system and brain, because the differentiation of nerve tissue is most active in fetus and newborn, and the differentiation of nerve is mainly controlled by thyroxine. Remember! Babies have only one chance to grow up. It is very important for pregnant women and lactating women to get enough iodine nutrition for the cognitive development of fetuses and babies.
2. Goiter
Goiter is common in women, with the highest incidence in adolescence and pregnancy. Chen Shiting explained that when the human body is short of iodine, due to the lack of raw materials, the synthesis of thyroid gland is reduced, but it will promote the secretion of thyroid stimulating hormone by pituitary gland, make the thyroid gland expand due to compensatory work, so as to maintain normal thyroid function, and finally form a visible lump in the neck, which is called "goiter".
3. Metabolic disorder is easy to gain weight
Iodine is the only nutrient in the human body that is directly proportional to calories, that is, the higher the calorie intake, the more iodine nutrition is needed. Simply put, iodine is closely related to the metabolism of the body. Studies have confirmed that if human iodine nutrition is insufficient, the metabolic rate of the body will also slow down, such as obesity, fatigue, fear of cold, cold hands and feet, listlessness and so on.
4. cardiovascular diseases
The diet of the elders at home is often light, so in the long run, we need to pay attention to the problem of iodine deficiency. Studies have found that if middle-aged and elderly people lack iodine for a long time, they may suffer from mental deterioration, slow response and even increase the incidence of cardiovascular diseases.
5. Endocrine disorders
If women lack iodine for a long time, it may affect endocrine balance, cause menstrual disorder and even infertility.
Excessive iodine intake, will the thyroid gland swell?
When iodine intake is excessive, it can be excreted with urine under normal circumstances. However, if some people consume too much iodine for a long time, the thyroid function will be continuously inhibited, and the concentration of thyroid hormone will also increase significantly, resulting in goiter. So it's not iodine deficiency that causes goiter. If you find goiter, you should go to a doctor for examination, and then you can know if you are hypothyroidism or hyperthyroidism.
Trick: Use iodine to make you healthier.
1. Choose iodized salt
Natural sea salt only contains a very small amount of iodine, which is not enough to provide enough iodine for human body; The guidelines of the World Health Organization (WHO) point out that iodization in edible salt is a safe and cost-effective policy, which can ensure that everyone can get enough iodine.
Therefore, when purchasing salt, it is suggested to choose iodized salt marked with "potassium iodate" or "potassium iodide" to replace ordinary salt and supplement the amount of iodine needed by the body. Adults' daily salt intake is still limited to 6 grams, which can meet daily needs.
2. Eat natural foods rich in iodine nutrition.
In addition to iodized salt, you can also eat natural foods rich in iodine (but it is not recommended to eat more), including kelp, seaweed, seaweed, marine fish, shellfish and so on. Every week, about/kloc-0 times, the knuckle size is not big, because the iodine content of kelp, kelp, seaweed and other foods is very high, and the iodine content per gram is hundreds of times the daily requirement.
Chen Shiting, for example, said that the iodine content of a sea knot is about 3 1.20 micrograms, which is equivalent to eating 1 month of iodized salt. Therefore, it is easy to cause goiter, especially those with a history of hyperthyroidism and autoimmune thyroid diseases, and should avoid eating foods with particularly high iodine content.
The most recommended way to supplement iodine nutrition is still to get iodine from salt, which will not cause the risk of iodine overdose.
Avoid cooking for a long time
Avoid cooking food at high temperature for a long time, because iodine and iodine added in natural food will be lost during cooking; Using cold salad or adding salt before cooking can reduce the loss of iodine.
How to judge iodine deficiency?
Goiter is an important indicator of iodine deficiency, but it is already a symptom of serious deficiency. In fact, we can directly measure urine iodine, and the urine iodine concentration is 100 ~ 199 per liter.