The period from birth to age 5 is crucial for building a foundation for height and bone health. However, many parents primarily focus on nutrition during infancy and the first year, leading to micronutrient deficiencies in subsequent years.

Among essential micronutrients, vitamins D3 and K2 play vital roles. D3 facilitates calcium absorption from the gut into the bloodstream, while K2 directs calcium to bone tissue. D3 deficiency reduces calcium absorption, and K2 deficiency leads to calcium deposits in the wrong places, impacting height and bone health.

A 2025 study published in Nutrition Journal found that children deficient in vitamin K2 have a 1.5 times higher risk of stunted growth compared to those with sufficient K2 levels. The World Health Organization (WHO) also warns that micronutrient deficiencies are linked to about 45% of deaths in children under 5, especially in developing nations.

Preschoolers remain at risk of bone micronutrient deficiencies without timely supplementation. Vitamin D3 is primarily synthesized through sunlight exposure. However, many children attend half-day or full-day preschool, limiting their outdoor playtime. The limited sun exposure, often coupled with protective clothing, leads to D3 deficiency. Meanwhile, vitamin K2, found in fermented foods, organ meats, and aged cheese, is rarely present in school meals.

According to the National Institutes of Health (NIH), sunlight can help the body synthesize vitamin D. However, achieving sufficient levels requires 5-30 minutes of sun exposure between 10 a.m. and 4 p.m. at least twice a week without sunscreen. This is also the period of highest UVB intensity, increasing the risk of skin cancer.

Even with a diet rich in milk, eggs, meat, and fish, the D3 and K2 content in common foods remains low compared to physiological needs. For instance, one egg contains only about 44 IU of vitamin D, while children one year and older need at least 600 IU daily, as recommended by the American Academy of Pediatrics (AAP).

Prolonged micronutrient deficiencies can slow bone development, reduce bone density, increase bone fragility, and hinder optimal height attainment in adulthood.

Vitamin K2 is found in fermented foods. Photo: Pexels

The AAP recommends 400 IU of vitamin D daily for children under 12 months and 600 IU daily for children one year and older to support bone development and enhance calcium absorption.

For calcium to effectively bind to bones and avoid the "calcium paradox," where calcium deposits in the wrong locations like blood vessels or soft tissues, the body requires vitamin K2, particularly the MK-7 form. This micronutrient transports and directs calcium to the skeletal system, increasing bone density and preventing stunted growth.

Proper micronutrient supplementation is essential for children's growth. Photo: Pexels

Vitamin K2 supplementation is considered essential from birth to age 5. Studies published in PubMed suggest a daily dose of 45-50 mcg of MK-7 is appropriate for children, supporting bone mineralization and height growth. Many D3 and K2 supplements offer age-appropriate dosages for easy parental use.

Due to the difficulty of obtaining sufficient D3 and K2 through diet alone, experts recommend that parents proactively supplement these vitamins through reputable products with transparent ingredient lists and safety testing. Choosing a product with high stability, good bioavailability, and ease of daily use is key to supporting a child's growth. The period from 2 to 5 years old, while often overlooked compared to the "first 1,000 days," is a period of rapid bone growth, significantly impacting adult height and bone density.

The Dan