VIETNAM NUTRITIONAL PORTAL
Micronutrient deficiencies are a significant nutritional concern among children, particularly during the school years, when their bodies require substantial amounts of energy and nutrients to support growth, brain development and physical activity. Notably, micronutrient deficiencies do not always present obvious symptoms, making them easy for parents to overlook.
Meanwhile, many families still believe that eating three main meals a day is sufficient to meet children's nutritional needs. In reality, eating enough food does not necessarily mean obtaining adequate nutrients. A diet that lacks diversity, is unbalanced across food groups or fails to meet the specific nutritional requirements of each developmental stage can still leave children deficient in essential micronutrients.
Therefore, in addition to three main meals, snacks, particularly afternoon snacks, can provide an opportunity to supplement energy and nutrients that may be lacking in the daily diet. However, how should snacks be planned? Which foods are suitable for children, and what role can milk play in these meals?
1. Micronutrient Deficiencies Among School-Age Children Remain a Concerning Form of “Hidden Hunger”
Reporter: Ms. Nguyen Lan Phuong, MSc, how would you assess the current situation of micronutrient deficiencies among Vietnamese children?
Dr. Nguyen Lan Phuong: Nutritional status during middle childhood (5–9 years) and adolescence (10–19 years) influences physical, cognitive and social development, with effects that can last throughout life and even extend to subsequent generations. This period also lays the foundation for adult health, as approximately 20% of adult height, 60% of bone mass and half of adult body weight are attained between the ages of 10 and 19. Therefore, to support rapid growth and development, children and adolescents have increasing requirements for energy, protein, iron and many other micronutrients.
In low- and middle-income countries, school-age children and adolescents face a wide range of nutritional challenges, from wasting and stunting to overweight, obesity, anemia and micronutrient deficiencies.
Prolonged undernutrition and micronutrient deficiencies directly affect children's physical development, learning ability and concentration. Meanwhile, being overweight during this stage increases the risk of developing noncommunicable diseases in adulthood.
In Vietnam, children and adolescents aged 5–19 are simultaneously facing the “triple burden of malnutrition.” According to the 2019–2020 National Nutrition Survey, among children aged 5–18, the prevalence of stunting was 14.8%, while the prevalence of wasting was 7.4%. These conditions were more concentrated in rural and mountainous areas. In contrast, overweight and obesity were more prevalent in urban areas, reaching 24.4%, nearly three times the rate recorded in mountainous regions.
Of particular concern, micronutrient deficiencies, also known as “hidden hunger,” remain prevalent. The term “hidden hunger” is used because micronutrient deficiencies do not produce symptoms as obvious as underweight or stunting, making them easy to overlook even when children appear to eat and engage in physical activities normally.
Reporter: Which micronutrients are school-age children most likely to lack, and how do these deficiencies affect their physical and intellectual development as well as their learning ability?
Dr. Nguyen Lan Phuong: School-age children are at particularly high risk of deficiencies in micronutrients such as iron, zinc, calcium and vitamin D. Deficiencies in vitamin A, B vitamins (B1, B6 and B12) and iodine also persist in many regions, especially in rural and mountainous areas. Each micronutrient has its own specific functions, but all directly influence children's physical development and learning ability.
First, iron is one of the micronutrients that play an important role in health and cognitive function. Iron deficiency causes anemia, leading to fatigue, poor concentration and reduced memory and learning ability. It is also one of the reasons children may struggle to retain what they have learned and feel sluggish during lessons.
Among girls, iron requirements increase substantially during adolescence to compensate for blood loss through menstruation. Therefore, adolescent girls are particularly susceptible to iron deficiency if their intake is inadequate. Prolonged iron deficiency during adolescence can affect not only physical growth but also cognitive function and immune health.
Second, zinc plays a direct role in growth in height and weight, immune function and taste perception. Children with zinc deficiency often experience poor appetite and frequent minor illnesses, potentially creating a vicious cycle of nutritional deficiencies.
Third, the school years are considered the second “window of opportunity,” after the “first 1,000 days of life,” for children to maximize their height growth potential. Calcium and vitamin D are indispensable during this period. These two closely related micronutrients play essential roles in height development and bone mineral density.
Finally, although they receive less attention, vitamin A, iodine, B vitamins and omega-3 fatty acids also play important roles in vision, thyroid function and brain development. Deficiencies in iodine and B vitamins can directly affect energy metabolism in nerve cells, thereby influencing children's learning ability.
Reporter: Many parents currently believe that as long as their children eat three main meals a day, their nutritional needs are being met. Is this view correct? How can parents recognize whether their children are at risk of micronutrient deficiencies even when they appear to eat normally?
Dr. Nguyen Lan Phuong: The belief that “eating enough at main meals means getting adequate nutrition” is not entirely accurate, because eating a sufficient quantity of food does not necessarily mean receiving sufficient nutritional quality.
Consuming enough food in terms of quantity only indicates that children are receiving sufficient energy (kcal); it does not confirm that their micronutrient requirements are being fully met. A child may feel full, gain weight steadily or even become overweight while still experiencing nutritional deficiencies if their diet lacks diversity and contains insufficient vegetables, fruits, seafood, milk and dairy products.
Moreover, the micronutrients children obtain from food may be lost during cooking or affected by the absorption process. Micronutrients are relatively sensitive to heat and light, while each child's ability to absorb them also varies depending on digestive system characteristics and interactions between nutrients.
Meanwhile, school-age children engage in intensive physical and mental activities while their bodies are also entering a period of rapid growth, particularly in height. Consequently, their micronutrient requirements per kilogram of body weight are substantial. This is why parents should not assess whether their children are receiving adequate nutrition solely on the basis of how much they eat or how much weight they gain.
3. What Role Do Snacks Play in Children's Growth and Learning Ability?
Reporter: Snacks are considered an important part of children's daily diets. In your opinion, what benefits do snacks offer for height development, immune function, brain function and long-term health during the school years?
Dr. Nguyen Lan Phuong: Snacks, also known as afternoon snacks, are not simply meals eaten “for enjoyment”; they play a genuinely important nutritional role for children. Because children's stomachs are still relatively small, they may not always be able to obtain sufficient energy and micronutrients from three main meals alone. In particular, the interval between lunch and dinner during the school day is often quite long, approximately 4–5 hours, even though children expend considerable energy on both studying and playing during this period.
When properly planned, snacks can provide additional nutrients essential for growth. In terms of height development, this is an appropriate time to offer foods rich in calcium, zinc, magnesium and vitamin D, such as milk, yogurt, cheese or nuts. Distributing calcium intake across several meals throughout the day also helps the body absorb it more effectively, rather than consuming an excessively large amount during a single main meal.
Snacks can also help maintain children's immune function throughout their time at school. Foods such as fresh fruits, smoothies and yogurt can provide vitamin C, vitamin A, vitamin E and zinc, thereby supplying essential nutrients needed to maintain a healthy immune barrier.
For brain function, a well-balanced snack can also help maintain stable blood glucose levels and reduce the risk of hypoglycemia between meals, which may cause children to become tired, irritable or less focused toward the end of the school day.
A light, healthy snack helps replenish glucose for the brain, maintaining alertness, memory and concentration during subsequent lessons. In addition, nutrients such as omega-3 fatty acids, iron, zinc and iodine found in foods directly support children's memory and cognitive function.
Beyond meeting immediate nutritional needs, snacks also contribute to long-term health. When children have an appropriate snack, they are less likely to become excessively hungry before their main meals, helping prevent habits such as eating too quickly, gulping down food or overeating in a short period. These habits are unfavorable for health and may contribute to an increased risk of metabolic disorders, overweight, obesity or stomach problems later in life.
Reporter: In school meal programs, particularly snacks or afternoon snacks at preschools and primary schools, which foods should be included, and how frequently should they be offered as part of children's daily diets?
Dr. Nguyen Lan Phuong: In my opinion, school snacks and afternoon snacks should follow the principles of being light, varied, easy to digest and high in micronutrient density. Snacks do not need to be large in quantity, but foods should be selected carefully for their nutritional quality. Different food groups should also be combined flexibly and rotated throughout the week to ensure dietary diversity.
First, milk and dairy products such as fresh milk, yogurt and cheese can be included daily, approximately 1–2 times per day, depending on the child's needs. These foods provide calcium, vitamin D, high-quality protein and beneficial bacteria (probiotics), thereby supporting height development and digestive health.
Fresh seasonal fruits such as oranges, apples, bananas, papaya and guava should also be regularly included in children's diets, either daily or at least 4–5 times per week. Fruits provide vitamin C, vitamin A, potassium and natural dietary fiber, contributing to stronger immunity and helping prevent constipation. Whenever possible, children should be offered whole fruits or cut fruit pieces rather than fruit juice, as this helps preserve dietary fiber and limits the intake of excessive amounts of natural sugars within a short period.
In addition, nuts and whole grains such as oats, walnuts, almonds, legumes and wholegrain bread can be included approximately 3–4 times per week. These foods provide slow-release energy and are rich in B vitamins, magnesium, zinc and essential fatty acids such as omega-3, helping sustain energy for both brain function and physical activity.
Reporter: What recommendations would you give parents when preparing daily meals and selecting foods to support their children's comprehensive development?
Dr. Nguyen Lan Phuong: Based on the points discussed above, parents can take several practical steps to help reduce the risk of micronutrient deficiencies in their children. First, they should diversify the foods offered each day, aiming to include all four major nutrient groups in each meal: protein, fats, carbohydrates, and vitamins and minerals. Menus should also be varied from day to day and week to week rather than repeatedly relying on familiar dishes, because the more diverse a diet is, the more likely it is to meet requirements for different micronutrients.
In addition to natural foods, parents may choose products that have been safely fortified with micronutrients, such as fresh milk fortified with vitamin D, calcium and zinc; iodized salt; seasoning powders fortified with iron and zinc; or cooking oils fortified with vitamin A. However, it is important to use these products according to nutritional needs and recommended instructions, rather than assuming that more supplementation is always better.
Food preparation methods also deserve attention to minimize nutrient losses. When cooking vegetables, parents should avoid prolonged cooking at high temperatures and may prioritize steaming or boiling until just cooked to preserve water-soluble vitamins such as vitamin C and B vitamins.
Snacks should not be overlooked, but the right foods must be selected. Instead of confectionery, sugary drinks or fast food, parents should prioritize milk, fruits and nuts. These options not only provide additional energy between main meals but also supply nutrients essential for growth.
Alongside a healthy diet, children also need appropriate sunlight exposure and regular outdoor physical activity. These activities help the body naturally synthesize vitamin D, thereby supporting calcium absorption and utilization and contributing to bone development.
Finally, to establish healthy and sustainable eating habits, parents also need to set a good example. Children often imitate the eating habits of adults in their families. Therefore, when parents eat a diverse range of foods and limit sweets and sugary drinks, they create a favorable environment for children to develop positive dietary choices from an early age. These habits are important not only during the school years but also as a foundation for children's long-term health.