Vitamin D

Prepared by Francisca Soto-Aguilar Bralic. MD, Ms Nutrition, Ms Global Public Health

← Back to Overview

Vitamin D is involved in the regulation of serum calcium and phosphate homeostasis, hence, in the development and maintenance of bone health; but also it has been hypothesized that Vitamin D plays a role in several other functions throughout the body, because Vitamin D receptors have been found in a large number of tissues including epidermis and cells of the immune system. Inadequate vitamin D levels can lead to rickets in children and osteomalacia in adults, amongst other health problems.

The following guidelines provide recommendations for vitamin D supplementation for children, based on the U.S. Recommended Dietary Allowances (RDAs), addressing age-specific needs and considerations.

These guidelines are intended for healthcare professionals to support optimal pediatric health outcomes.

Recommended Dietary Allowances (RDA) for Vitamin D in Children

The U.S. Institute of Medicine (IOM) (now the National Academy of Medicine) provides RDAs for vitamin D, which are based on age and need to be met through a combination of dietary intake and supplementation.

*AI=Adequate Intake

Vitamin D Supplementation Recommendations

Infants (0-12 months)

Rationale: Breast milk is often insufficient in vitamin D, particularly in areas with limited sunlight exposure. Milk and formula are usually vitamin D fortified, and commercial vegetable drinks and formulas can be as well. The American Academy of Pediatrics (AAP) recommends that all infants receive 400 IU of vitamin D daily, beginning in the first few days of life, regardless of whether they are breastfed or formula-fed.

Sources:

• Breastfed infants: Daily supplementation with 400 IU of vitamin D per day is recommended.
• Formula-fed infants: If infants consume less than 1 liter (32 ounces) of vitamin D-fortified formula per day, supplementation with 400 IU of vitamin D per day is recommended.

Considerations: It is not recommended that children under 12 months old drink milk, so for this stage, infant formula should be the alternative to breastmilk and the healthcare provider can check its vitamin D fortification, usually roughly on 40 UI of vitamin D per 100 ml of formula. Infants with chronic fat malabsorption, taking antiseizure medications, as well as children with dark skin, those who live in northern latitudes, or those who are exclusively breastfed should receive supplementation, as they are at greater risk for deficiency. Children with increased risk of vitamin D deficiency may need higher doses of supplementation to achieve normal vitamin D status, and monitoring of serum levels after supplementing should be taken at 3 month intervals.

Summary: Daily supplementation with 400 Ul of Vitamin D per day is recommended for 0-12 months infants, except for formula-fed infants that consume 1 liter or more (32 ounces) of vitamin-D fortified formula per day.

Toddlers (1-3 years)

Rationale: As children grow, the need for vitamin D increases to support bone development and immune function.

Recommendation: The RDA for children aged 1 to 3 years is 600 IU of vitamin D per day. This can be obtained from a combination of dietary intake and sunlight exposure, but at this stage a supplement will be preferred in most cases.

Sources:

• Diet: Encourage the consumption of vitamin D-rich foods, such as fortified drinks and fortified cereals.
• Sunlight: While sunlight exposure can help the body synthesize vitamin D, toddlers should still be encouraged to avoid prolonged sun exposure due to the risk of skin damage.
• Supplement: Supplementation with 600 UI of vitamin D per day might be recommended in most cases.

Considerations: Supplementation may be necessary for children with limited sun exposure or dark skin, and toddlers that are breastfed.

Summary: Daily supplementation with 600 Ul of Vitamin D per day is recommended in most cases for 1-3 year old toddlers, unless health-professional’s assessment of diet and sunlight exposure at this stage states they are sufficient.

Children (4-8 years)

Rationale: As children enter school age, their diet and lifestyle may limit their vitamin D intake. Additionally, insufficient intake during these years can affect long-term bone health.

Recommendation: The RDA for children aged 4-8 years is 600 IU per day. Children who do not regularly consume fortified foods or have limited sun exposure should be considered for supplementation.

Sources:

• Diet: Encourage foods such as fortified drinks and fortified cereals.
• Sunlight: While vitamin D can be obtained from sunlight exposure, safety precautions should be taken to prevent sunburn.
• Supplement: Supplementation with 600 Ul of vitamin D per day might be recommended.

Considerations: In regions with low sunlight for extended periods (e.g., during winter months), supplementation may be necessary.

Summary: Daily supplementation with 600 Ul of Vitamin D per day might be recommended in 4-8 year old children, after a proper assessment of diet and sunlight exposure, considering differences through the seasons of the year and serum concentration if available.

Adolescents (9-18 years)

Rationale: Adolescents undergo rapid growth and bone mineralization, making adequate vitamin D intake essential to optimize bone density and support overall health.

Recommendation: The RDA for vitamin D in adolescents is 600 IU per day. As this age group may have dietary habits that are low in vitamin D, supplementation may be beneficial, especially for those who avoid common commercial vitamin D fortified products.

Sources:

• Diet: Encourage intake of fortified drinks. Vegan or lactose-intolerant adolescents may need fortified plant-based milks and other alternatives.
• Sunlight: Encourage safe sun exposure for vitamin D synthesis, but balance this with skin cancer prevention measures.
• Supplement: Supplementation with 600 Ul of vitamin D per day might be recommended.

Considerations: In regions with low sunlight for extended periods (e.g., during winter months), supplementation may be necessary.

Summary: Daily supplementation with 600 Ul of Vitamin D per day might very well be recommended in 9-18 year old adolescents, after a proper assessment of diet and sunlight exposure, considering differences through the seasons of the year and serum concentration if available.

Special Populations at Risk for Vitamin D Deficiency

Certain children are at a higher risk for vitamin D deficiency and may require supplementation:

• Exclusively Breastfed Infants: All exclusively breastfed infants and toddlers should receive 400 or 600 IU/day of vitamin D supplementation, respectively.
• Children with Darker Skin Tones: Higher levels of melanin reduce the skin’s ability to synthesize vitamin D from sunlight. These children are at increased risk of deficiency and might benefit from a vitamin D supplement.
• Children in Northern Latitudes: During the winter months, there is limited sunlight, reducing the ability to synthesize vitamin D. Supplementation is often recommended during these months.
• Obese Children: Obesity is associated with lower bioavailability of vitamin D, as the vitamin is sequestered in adipose tissue, reducing its effectiveness. Obese children may require a higher dose of supplementation.
• Children with Limited Sun Exposure: Children who are always indoors, use sunscreen regularly, or wear clothing that covers most of their skin may need supplementation.
• Children with Chronic Conditions: Conditions like cystic fibrosis, Crohn’s disease, or celiac disease can impair the absorption of vitamin D, requiring higher doses of supplementation.

Safety and Monitoring

• Toxicity: Vitamin D toxicity is rare but can occur with excessive supplementation. Symptoms include nausea, vomiting, poor appetite, constipation, weakness, and in severe cases, kidney damage.
• Upper Intake Levels: The upper limits for vitamin D intake are established to avoid toxicity. These limits should not be exceeded unless advised by a healthcare provider. The recommended upper limits are:

   

  • Infants (0-6 months): 1,000 IU/day
  • Infants (7-12 months): 1,500 IU/day
  • Children (1-3 years): 2,500 IU/day
  • Children (4-8 years): 3,000 IU/day
  • Children (9-18 years): 4,000 IU/day
• Monitoring: Regular monitoring of vitamin D levels is recommended for children at risk for deficiency, particularly those receiving supplementation or with conditions affecting absorption. Serum 25-hydroxyvitamin D levels should be maintained between 20 ng/mL and 50 ng/mL for optimal health (50-125 nmol/L).

References

1. Dietary Reference Intakes for Calcium and Vitamin D. Institute of Medicine (US) Committee to Review Dietary Reference Intakes for Vitamin D and Calcium; Ross AC, Taylor CL, Yaktine AL, et al., editors. Washington (DC): National Academies Press (US); 2011.
2. Gartner, L. M., Greer, F. R., & Section on Breastfeeding and Committee on Nutrition. American Academy of Pediatrics (2003). Prevention of rickets and vitamin D deficiency: new guidelines for vitamin D intake. Pediatrics, 111(4 Pt 1), 908–910. https://doi.org/10.1542/peds.111.4.908

← Back to Overview