OVERVIEW

What is zinc deficiency in children?

Zinc deficiency in children refers to a condition where the body's zinc levels are insufficient to meet physiological needs due to various reasons.

Symptoms of zinc deficiency are systemic and often include poor appetite, stunted growth, delayed sexual development, skin rashes, and increased susceptibility to infections.

Severe zinc deficiency may also lead to immune suppression, frequent infections, bullous pustular dermatitis, diarrhea, and hair loss.

It is important to note that symptoms of zinc deficiency may overlap with those of other nutrient deficiencies. Therefore, diagnosis requires assessing zinc intake and conducting relevant tests.

Is zinc deficiency common in children?

Children are a high-risk group for zinc deficiency.

Zinc deficiency is widespread among children globally, particularly in developing countries, where it is more prevalent. Approximately 30% of the world's population has zinc deficiency, with the majority being children in developing nations.

What role does zinc play in the body?

Zinc is the second most abundant trace element in the human body, following iron.

Zinc is involved in protein metabolism and synthesis, acts as a cofactor for over 300 enzymes, participates in nucleic acid metabolism, helps maintain cell membrane stability, and has neuroregulatory functions.

Thus, zinc deficiency can lead to systemic developmental disorders, affecting multiple bodily systems.

Which foods are rich in zinc?

Animal-based foods are rich in highly absorbable zinc, including meat, fish, egg yolks, organ meats, and oysters.

Among plant-based foods, nuts such as walnuts and peanuts contain relatively high zinc levels. Other plant-based foods generally have low zinc content and poor absorption, making strict vegetarians more prone to zinc deficiency.

Does poor appetite in children always indicate zinc deficiency?

Not necessarily, as symptoms of zinc deficiency can resemble those caused by other nutrient deficiencies.

Poor appetite may result from various factors, including eating habits and food preferences, and does not always indicate a medical condition. A thorough dietary review, physical examination, and laboratory tests are needed to confirm zinc deficiency.

SYMPTOMS

What are the common manifestations of zinc deficiency in children?

1. Growth retardation: Low weight and short stature, which can be restored after zinc supplementation.

2. Neurodevelopmental disorders: Cognitive impairment and developmental delays, which can also be improved with zinc supplementation.

3. Loss of appetite and pica: Zinc deficiency reduces taste bud function, making food tasteless for children, leading to poor appetite. Some children may eat non-food items like dirt, wall plaster, paper, or coal slag, which can be corrected with zinc supplementation.

4. Delayed sexual development: Late onset of puberty and delayed appearance of secondary sexual characteristics.

5. Recurrent infections: Increased susceptibility to pneumonia, diarrhea, colds, and other illnesses.

6. Skin changes: Symptoms like dry skin, rashes, oral ulcers, hair loss, and delayed wound healing may occur.

What severe symptoms may occur in children with serious zinc deficiency?

Severe zinc deficiency, in addition to common symptoms, can lead to significant immune suppression, resulting in recurrent and serious infections such as persistent pneumonia, sepsis, and diarrhea.

It may also cause pustular or bullous dermatitis, with large blisters on the skin followed by peeling.

What serious consequences can zinc deficiency have in children?

If zinc deficiency remains untreated for a long time, it can lead to developmental delays in various aspects, affecting the child's intelligence and physical growth.

Severe zinc deficiency-induced immune suppression may make infections difficult to control, potentially posing life-threatening risks. In developing countries, zinc deficiency is one of the top ten causes of increased disease prevalence and mortality.

CAUSES

What Causes Zinc Deficiency in Children?

1. Insufficient Zinc Sources in Diet: Zinc deficiency may occur if the diet lacks animal-based foods. Meat, fish, eggs, dairy, and organ meats contain zinc and can help replenish zinc levels.

2. Increased Physiological Demand: When the body's demand rises without corresponding supplementation, zinc deficiency may develop. Conditions like childhood growth, diarrhea, or infections increase zinc requirements.

3. Absorption Disorders: High dietary fiber or phytic acid can reduce zinc absorption. Excessive intake of calcium or iron may also impair zinc absorption. Since zinc is primarily absorbed in the small intestine, diseases like short bowel syndrome or steatorrhea can hinder absorption.

4. Excessive Zinc Loss: Zinc is lost in cases of burns, hemolysis, trauma, blood loss, or hypoalbuminemia, requiring additional supplementation.

5. Rare Genetic Disorders: Acrodermatitis enteropathica, a hereditary condition, impairs intestinal zinc absorption.

6. Environmental Factors: Lead poisoning or excessive cadmium intake (e.g., from secondhand smoke exposure) may contribute to zinc deficiency.

DIAGNOSIS

How to determine zinc deficiency in children?

1. Symptom assessment:

• Low zinc content in the diet, lack of animal-based foods like meat, and a diet mainly consisting of grains and vegetables may lead to zinc deficiency;
• Presence of symptoms such as developmental delays or taste disorders;
• High-risk factors for zinc deficiency: diarrhea, burns, recurrent infections, etc.

2. Laboratory tests:

• Decreased plasma zinc levels, which is a common diagnostic criterion.

What tests should be done if zinc deficiency is suspected in children?

If zinc deficiency is suspected, the following tests should be performed: blood biochemistry, complete blood count (CBC), CRP, plasma zinc, and alkaline phosphatase.

1. Blood biochemistry: Evaluates liver and kidney function to assess overall nutritional status.
2. CBC and CRP: Checks for infections or anemia.
3. Plasma zinc: Measures zinc levels in the blood. Mild deficiency may not show changes, but moderate to severe deficiency often results in decreased levels.
4. Alkaline phosphatase: Levels may also decrease with zinc deficiency.

What is diagnostic zinc supplementation?

If test results are normal but symptoms persist, diagnostic zinc supplementation may be considered.
For children with typical zinc deficiency symptoms, oral elemental zinc at 1mg/(kg*d) can be administered for assessment.

The dosage is calculated as 1mg per kg of body weight. For example, a 10kg child would receive 10mg once daily. After one month, observe whether symptoms improve. Significant improvement suggests zinc deficiency.

TREATMENT

Which department should I visit for zinc deficiency in children?

Pediatric Internal Medicine, Child Health Care

Can zinc deficiency in children heal on its own?

Zinc deficiency in children is caused by an imbalance between zinc supply and demand in the body. It cannot heal on its own and requires additional zinc supplementation for recovery.

How to treat zinc deficiency in children?

1. Zinc supplementation.
Zinc is well absorbed orally and can be taken orally. Supplement with 0.5–1.5 mg of elemental zinc per kilogram of body weight daily, not exceeding 20 mg in total. Continue supplementation for 3–6 months. Zinc sulfate or zinc acetate can be used.

2. Adjust dietary structure.
Increase intake of animal-based foods to ensure adequate nutrition. Breastfed infants should be prioritized, as breast milk is rich in zinc and has high absorption rates.

3. Treat infections and other complications.

When does zinc deficiency in children require hospitalization?

Zinc deficiency usually does not require hospitalization.

Hospitalization may be considered only in cases of severe zinc deficiency leading to infections. The child may develop complications such as sepsis, pneumonia, or diarrhea. Symptoms include persistent high fever, lethargy, confusion, rapid breathing, anuria, mottled skin, or cyanosis.

DIET & LIFESTYLE

What should children eat when they are zinc deficient?

Animal-based foods are rich in zinc, so increasing the intake of meat, liver, egg yolks, fish, and other animal-derived foods can help boost zinc levels and prevent deficiency.

Especially for infants transitioning to solid foods, it's important to include more meat in their diet. Avoid feeding them only plain rice porridge with milk, as this can easily lead to deficiencies in various nutrients.

PREVENTION

How to Prevent Zinc Deficiency in Children?

Breastfed babies should be given breast milk whenever possible. Nursing mothers should consume zinc-rich foods such as meat, animal organs, egg yolks, and fish.

After introducing solid foods, ensure the child eats animal-based foods daily, such as meat puree, liver paste, and egg yolks. Avoid feeding only rice porridge or thin cereals.

What Is the Daily Recommended Zinc Intake?

• 0–5 months: 2 mg/day
• 5–12 months: 3.5 mg/day
• 1–3 years: 4 mg/day
• 4–6 years: 5.5 mg/day
• 7–10 years: 7.0 mg/day
• 11–13 years: Boys 10 mg, Girls 9 mg
• 14–17 years: Boys 11.5 mg, Girls 8.5 mg
• Nursing mothers: 12.0 mg/day

What Happens If Too Much Zinc Is Consumed?

Extra zinc supplementation does not enhance growth and development. If a child is not zinc-deficient, additional zinc will not improve appetite or development. Only zinc-deficient children benefit from supplementation.

1. Zinc itself is not harmful, and dietary zinc does not cause harm.

2. Acute zinc poisoning is rare and requires extremely high doses—over 2,000 mg at once for adults, which is 100 times the recommended intake.

3. Long-term supplementation of 50–100 mg or more (10 times the recommended intake) may cause chronic toxicity and copper deficiency.