trace element barriers
Introduction
Introduction to trace element disorders Trace element barrier: Some elements have less body content, need to be taken through food, and have some physiological functions as trace elements. Among them, there are essential trace elements (8 kinds of iodine, zinc, selenium, copper, molybdenum, chromium, cobalt and iron), among which iron, iodine and zinc are easily deficient micronutrients; possible elements (manganese, silicon, boron, antimony, 5 kinds of nickel); elements that are potentially toxic, but may have essential functions (fluorine, cadmium, mercury, arsenic, aluminum, lithium, tin) at low doses. Essential trace elements are essential enzymes for enzymes and vitamins; constitute or participate in the action of hormones; participate in nucleic acid metabolism; work together with macronutrients and macronutrients. The lack of trace elements or excessive toxicity of trace elements can cause the pathological state of the body. Commonly used in pediatrics are zinc deficiency, iodine deficiency, zinc poisoning, and iodine poisoning. basic knowledge The proportion of illness: 0.002% - 0.003% Susceptible people: children Mode of infection: non-infectious Complications: developmental delay gingivitis conjunctivitis narcolepsy depression
Cause
Causes of trace element disorders
1. Insufficient intake
Animal foods are not only rich in zinc but also easy to absorb. Plant foods contain less zinc. Therefore, vegetarians or those who do not like animal foods are prone to zinc deficiency. Total parenteral nutrition such as zinc deficiency can cause severe zinc deficiency.
2, absorption barriers
Diarrhea caused by various reasons can hinder the absorption of zinc. Grains contain a lot of phytic acid and crude fiber, which can be combined with zinc to hinder its absorption. The zinc content of milk is similar to that of breast milk, about 45.9-53.5mol/ L (300-350g/dl) but the absorption rate of zinc in milk (39%) is much lower than that of breast milk (65%), so long-term pure milk feeding can also cause zinc deficiency. Enteropathic acral dermatitis is an autosomal recessive disorder. Because the small intestine lacks a carrier for absorbing zinc, it can be severely deficient in zinc.
3, the need to increase
In the early stages of growth and development, or during tissue repair, or during malnutrition recovery, zinc requirements may increase and relative zinc deficiency may occur.
4, too much loss
Such as repeated bleeding, hemolysis, long-term sweating, large area burns, proteinuria and the application of metal chelating agents (such as penicillamine) can lead to zinc deficiency due to excessive zinc loss.
Prevention
Trace element disorder prevention
The daily supply of zinc is: 0-6 months 3mg, 7-12 months 5mg, 1-10 years old 10mg, >10 years old 15mg. Promote breastfeeding, usually advocate a balanced diet, quit the picky eaters, partial eclipse, snacking habits, such as premature babies, artificial feeding, malnourished children, long-term diarrhea, large-area burns, etc. Appropriate zinc supplementation. Human colostrum has a high zinc content of 306mol/L (2000g/dl), and the zinc absorption rate in human milk is also high. Therefore, breastfeeding of infants is beneficial to prevent zinc deficiency. However, with the increase of age, it is necessary to add food supplements on time, such as egg yolk, lean meat, fish, animal offal, beans and nuts, which are rich in zinc, and should be properly arranged daily. Artificial breastfeeding without breastmilk is best done with infant formula or milk powder that is fortified with moderate amounts of zinc.
There are a variety of foods that are fortified with zinc. It is necessary to pay attention to its zinc content. It can be used for a long time to eat a variety of foods that strengthen zinc. Too much zinc can cause poisoning. If excessive intake of zinc can cause acute zinc poisoning, vomiting, diarrhea and other gastrointestinal symptoms, zinc fog inhalation may have low fever and cold-like symptoms; chronic zinc poisoning may have anemia and iron deficiency, animal experiments can cause liver and kidney function And immune damage.
Complication
Trace element disorder complications Complications, retardation, gingivitis, conjunctivitis, narcolepsy, depression
It is characterized by slow taste, poor appetite, ecstasy, growth retardation, dermatitis or wound healing. Then, growth retardation or cessation, short stature, delayed sexual development. Visual dark adaptation ability is reduced, and severe cases may have corneal opacity. Poor immunity, repeated infections, and wounds are not easy to heal. Skin lesions are characteristically distributed, mainly distributed around the mouth and anus. Gingivitis, glossitis, conjunctivitis, etc. may also occur. Can affect brain function, manifested as impatience, lethargy, depression or poor learning ability. Mainly based on lack of medical history, clinical manifestations, low blood zinc, and combined treatment effects and other comprehensive judgments.
Symptom
Symptoms of trace element disorders Common symptoms Chondroital dysplasia and... Inevitable premature thyroid function hypothermia
The severity of clinical manifestations depends on the degree of iodine deficiency, the duration and age of the disease, iodine deficiency during the fetal period can cause stillbirth, premature birth and congenital malformation, neonatal thyroid dysfunction, and thyroid in children and adolescence Swelling, endemic hypothyroidism, subclinical hypothyroidism in children with long-term mild iodine deficiency, often accompanied by physical growth.
Examine
Examination of trace element disorders
1 serum total T3, T4 or free T3, T4 decreased significantly, and TSH increased. 2 urinary iodine <25g / g creatinine, is a favorable evidence for the determination of iodine deficiency in individuals. In addition, the results of urinary iodine screening are a simple and effective method to determine whether there is iodine deficiency in the area. If the urinary iodine median <20 (g/L) is a severe iodine deficiency zone, 20-49 (g/ L) is a moderate iodine deficiency zone, 50-99 (g/L) is a mild iodine deficiency zone, and >100 (g/L) is normal.
Diagnosis
Diagnosis and identification of trace element disorders
The fasting serum zinc concentration (Ao) is measured as the basal level, and then given a standard diet (according to 20% of total calories in the whole day, protein is 10%-15%, fat is 30%-35%, carbohydrate is 50%- 60%), 2 hours to review serum zinc (A2) according to the formula PICR = (A0-A2) / Ao × 100%, such as PICR> 15% suggest zinc deficiency.
Different parts of hair and different washing methods can affect the measurement results. The zinc concentration decreases when zinc deficiency is mild, the hair growth slows down when severe, and the zinc value increases, so zinc can not reflect the zinc nutrition status in the near future.
According to the history and clinical manifestations of zinc deficiency, serum zinc <11.47mol/L, PICR>15%, zinc treatment can be diagnosed.
