Why do children still suffer from rickets despite daily vitamin D supplementation?

Many parents believe that giving their children daily vitamin D serves as a 'shield' against rickets. However, in clinical practice, many children still suffer from growth delays and stunting despite strict supplementation schedules. This phenomenon stems from gaps in nutritional practices at home.

According to Dr. Le Thi Huong Giang, Head of the Department of Nutrition and Dietetics at Hospital 19-8, vitamin D acts as an essential carrier that helps the body efficiently absorb calcium and phosphorus to build bone structures. A lack of vitamin D seriously affects the skeletal system, leading to the risk of rickets, delayed motor milestones such as rolling, crawling, walking, or even bone deformities. Data from the National Institute of Nutrition shows that 20-40% of Vietnamese children are deficient in this micronutrient.

The most common mistake is focusing solely on vitamin D while neglecting calcium. Biologically, vitamin D is merely the 'transporter' of calcium into the blood and bones; if the diet lacks calcium—found in milk, yogurt, cheese, small fish, and dark leafy greens—the bone mineralization process cannot occur. Furthermore, misconceptions that breast milk contains sufficient vitamin D, over-reliance on low-dosage multivitamins, or inconsistent supplementation all undermine the protective benefits.

Experts also note that underlying medical conditions affecting the liver, kidneys, or digestive absorption can prevent the body from utilizing vitamin D even with consistent supplementation. Parents should closely monitor warning signs such as frequent night sweats, crying at night, delayed closure of the fontanelle, or stunted growth.

Finally, sun exposure is merely a supportive measure and cannot entirely replace recommended medical dosages. Any high-dose or prolonged vitamin D supplementation must be directed by a physician to avoid the risk of hypercalcemia and ensure the safety of the child's development.