☀️ VITAMIN D – THE “KEY TO STRONG BONES” AND SUPPORTING OVERALL DEVELOPMENT IN CHILDREN

When it comes to Vitamin D, many parents immediately think of supplementing it to help strengthen their child’s bones and support healthy height development. However, Vitamin D plays a much broader role than just maintaining bone health.

In fact, Vitamin D is involved in regulating calcium and phosphorus levels, bone metabolism, and many other important biological processes in the body. In particular, Vitamin D deficiency can develop silently without obvious symptoms. However, if it persists over time, it may negatively affect a child’s health.

❓ So, how much Vitamin D does a child need each day? When is supplementation necessary? Does every child need to take Vitamin D? And how can parents provide an adequate amount without causing excessive intake?

Let’s join Dr. Pham Thi Thuy Trang, Specialist Level 1 in Pediatrics – Head of the Department of Pediatrics, to learn more about the important role of Vitamin D and appropriate supplementation for children in the article below!

1. What is Vitamin D?

• Vitamin D is a fat-soluble vitamin that plays an essential role in maintaining stable calcium levels in the blood, supporting bone metabolism, and participating in many other metabolic processes in the body.
• The body obtains Vitamin D partly from dietary sources such as fatty fish liver, liver and other organ meats, egg yolks, and foods fortified with Vitamin D such as milk and cereals. Vitamin D is also synthesized in the skin following sun exposure. It is then metabolized by the liver and kidneys into its most biologically active form.

Daily Vitamin D requirements:

• 0–12 months: 400 IU per day
• 1–18 years: 600 IU per day

Vitamin D status based on blood 25-hydroxyvitamin D [25(OH)D] levels, according to the 2019 Endocrine Society guidelines:

• Optimal: > 30 ng/mL
• Insufficient: 12–30 ng/mL
• Deficient: < 12 ng/mL

2. Vitamin D Deficiency in Children: A Common Condition with Consequences That Should Not Be Overlooked

• Vitamin D deficiency is relatively common among children and may develop silently without obvious symptoms. Several recent surveys have shown that the proportion of children with low Vitamin D levels remains a concern.
• In India, a 2024 survey involving 38,762 children under 18 years of age found that 66.4% had Vitamin D levels below 20 ng/mL.
• In China, a 2025 survey of 1,827 children aged 6–17 years reported that 45% had Vitamin D levels below 20 ng/mL.

⚠️ Importantly, Vitamin D deficiency often does not cause noticeable symptoms in its early stages. However, prolonged deficiency may lead to problems related to bone health, including:

🔸 Reduced calcium and phosphorus absorption, affecting normal bone mineralization.

🔸 Weak bones and reduced bone mineral density, increasing the risk of bone deformities or fractures.

🔸 Bone pain, muscle pain, and fatigue in some cases.

🔸 In growing children, prolonged Vitamin D deficiency may affect normal growth and skeletal health.

👉 Therefore, parents should not wait until their child develops symptoms before paying attention to Vitamin D status. It is important to ensure an appropriate diet, adequate outdoor activity, and awareness of the child’s individual risk factors. When clinically indicated, a doctor may recommend a 25-hydroxyvitamin D [25(OH)D] blood test to assess Vitamin D status and provide appropriate supplementation advice.