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Nutritional balance is the most important thing
Whether to give zinc supplements to children is an issue that many parents are anxious about.
The child does not eat well and wants to supplement zinc;
The child has thinning hair and wants to supplement zinc;
The child does not sleep well and wants to take zinc supplements;
Children often have colds and want to supplement zinc;
......
As an essential trace element, zinc is indeed important, but your child is not necessarily deficient, so let's talk about what you need to know about zinc supplementation.
How much zinc does a child need per day?
Unlike the body's need for hundreds or thousands of milligrams of calcium, the body's need for zinc is only in the single digits to the tens of digits.
Table 1 shows the recommended dietary intake (RDA)/AI, and tolerable maximum intake (UL) for zinc for children of all ages recommended by the World Health Organization (WHO) and the National Academy of Medicine (NAM).
Description: The WHO's recommended UL is based on a zinc intake cut-off value that affects copper absorption (laboratory determination), which is significantly higher than the UL established by NAM in the United States more than 20 years ago. The International Zinc Nutrition Advisory Group also supports the use of values above the NAM definition.
Table 2 Industry standards issued by the National Health Commission in 2017
Table 3 Examples of zinc content in foods
It can be seen that our body's demand for zinc is not "so high".
Zinc is also found in a wide range of everyday foods, including animal foods (such as meat, crustaceans, shellfish, etc.), as well as certain plant foods (such as chickpeas, cashew nuts, and pumpkin seeds), and among plant foods, fortified ready-to-eat cereals are the most common source of zinc.
There is an adequate source of dietary zinc in a typical mixed diet, and zinc supplementation is not required in a balanced diet. For ovo-lacto-vegetarians, it is recommended to consume more fortified or whole grains, legumes, milk, eggs, nuts, and seeds to obtain adequate zinc, rather than preferably supplementing the inadequate intake.
What are the signs of zinc deficiency in children?
There are no specific clinical manifestations of marginal or mild zinc deficiency. The main manifestations are growth retardation, delayed sexual and bone development, dermatitis (mild psoriasis-like dermatitis), diarrhea, recurrent respiratory or gastrointestinal infections, low appetite, abnormal sense of taste, hair loss, and behavioral changes. Marginal and mild zinc deficiency or zinc nutritional deficiencies are caused by insufficient zinc in food.
Severe zinc deficiency is an inherited form of zinc malabsorption, usually underpinned by a genetic mutation. Clinical manifestations include transient neonatal zinc deficiency and enteropathic acral dermatitis, which is characterized by dermatitis (usually erythematoid, scaly, vesicular bullous or pustuular lesions on the extensor surfaces of the oral, perianal or extensor extremities), severely decreased immune function, frequent infections, diarrhoea, and alopecia.
How is zinc deficiency diagnosed? Who should do it?
Plasma/serum zinc concentrations are often used to assess for zinc deficiency (the lower limit of serum zinc is 65 mcg/dL or 10.07 micromol/L for < 10-year-old children), but unfortunately the sensitivity of this test (patients with mild-to-moderate zinc deficiency may have normal serum zinc levels and may miss the diagnosis) and specificity (zinc levels may be elevated in acute catabolic states and may cause misdiagnosis) are limited.
Table 4 Low plasma zinc levels
It is not suitable for routine screening in healthy children without an indication because it requires venous blood (using a zinc-free blood collection tube) and is not readily available for analysis in many clinical laboratories because samples may be contaminated.
For high-risk groups (delayed addition of complementary foods after 6 months of age, high-phytic acid diet, clay pica), insufficient dietary intake, clinical symptoms pointing to zinc deficiency, or children with underlying diseases such as enteropathic acrodermatitis, Crohn's disease, cystic fibrosis, sickle cell disease, liver disease, parenteral nutrition, kidney disease, or severe malnutrition, plasma zinc concentration testing is recommended. If necessary, a controlled trial before and after treatment is required to assess the effectiveness of zinc supplementation to presume the diagnosis of zinc deficiency (i.e., 2 to 4 weeks of diagnostic therapy to assess for symptomatic resolution and improvement in growth).
In some cases, further tests (eg, serum alkaline phosphatase, C-reactive protein, zinc levels in neutrophils, lymphocytes, or red blood cells) are even needed to aid in the clinical assessment.
However, for the vast majority of children with no underlying diseases, non-high-risk groups, and non-vegetarian diets, routine plasma zinc concentration testing is not necessary if there is no abnormality in dietary assessment.
What conditions may require zinc supplementation?
There have been some studies showing the benefit of zinc supplementation in the treatment or prevention of diarrhoea or pneumonia in children in resource-limited settings (while the shortening and alleviating effects of colds are controversial and not recommended for routine use), but this benefit has not been observed in resource-rich settings.
China is a vast country, and children in different regions (urban and rural) and with different eating habits (balanced diet or severe picky eating) are in different situations, so it is not possible to generalize, and it is necessary to assess the specific "group of people" to which each child should be classified according to their actual feeding and other conditions. ”
For infants in resource-limited countries, meat and liver as the first complementary food supplement have been shown to be a practical and effective solution to zinc and iron deficiencies.
Current studies have varied about the growth benefits of zinc supplementation, which parents are most looking forward to, with the best results suggesting only a "modest benefit" and more data warning of the risks associated with supplementation with a single nutrient (zinc supplementation affects copper and iron absorption and increases the risk of vomiting).
The most important conclusion: zinc has no effect on the growth of individuals without underlying zinc deficiency, i.e., zinc itself has no growth-promoting pharmacological effects.
Can regular zinc supplementation cause poisoning in my child?
Zinc supplementation is rarely toxic, and no symptoms occur when consuming up to 10 times the recommended daily intake.
Therefore, it is safe to give high-dose zinc supplementation to children for a short period of time (10 to 14 days) in the treatment of acute or persistent diarrhea.
Studies have shown that 21 mg of zinc per day for infants and children in addition to dietary zinc intake has no significant effect on the status of copper and iron in the body.
Table 5 Comparison of commonly used zinc supplements
Adults can tolerate zinc up to 100 mg/day, but long-term use of high-dose zinc (more than 150 mg/day) may lead to deficiencies in other minerals such as iron and copper.
This is because the absorption of each mineral needs to be carried through the body's "porters" – transporters – and if the "porters" are busy carrying zinc, there will obviously not be enough of the remaining porters to carry other minerals such as iron and copper.
However, it is important to note that high doses of zinc can have adverse effects and can cause nausea, vomiting, decreased appetite, diarrhea, headache, anemia, neurological lesions, and dyslipid dystrophy.
When 1-2 g of zinc sulfate is ingested acutely, it can irritate and corrode the digestive tract, causing malignancy and vomiting. In contrast, high doses of zinc compounds can also cause tubular necrosis or interstitial nephritis, leading to acute renal failure.
Therefore, the nutrients at home should also be strictly managed like medicines, and should not be placed in places where children can reach them at will.
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Bibliography:
[1]膳食微量元素概述. UpToDate
[2] Zinc deficiency and supplementation in children. UpToDate
[3] Expert consensus on the clinical prevention and treatment of zinc deficiency in children. Journal of Pediatric Pharmacy
[4] Recommendations for the prevention and treatment of micronutrient deficiencies in children. Chinese Journal of Pediatrics
[5] Practical Child Health Care (2nd Edition), People's Medical Publishing House
[6] Reconsidering the Tolerable Upper Levels of Zinc Intake among Infants and Young Children: A Systematic Review of the Available Evidence.nutrients
[7] A Review of Dietary Zinc Recommendations. Food & Nutrition Bulletin
Source of this article: Zhuo Zheng Science Health Expresse Editor: Moon
*The Medical Profession strives to be professional and reliable in its published content, but does not make any commitment to the accuracy of the content; The parties involved are invited to separately check when adopting or using this as a basis for decision-making.
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