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Information on the latest vitamin D news and research.

Find out more information on deficiency, supplementation, sun exposure, and how vitamin D relates to your health.

Study shows daily high-dose supplementation of vitamin D improves symptoms associated with sickle cell disease

A recent study published by the Journal of Pediatric Hematology Oncology found that high dose vitamin D supplementation improved markers of disease severity and inflammation in children and young adults with sickle cell anemia.

Sickle cell disease (SCD) is a hereditary condition in which red blood cells become irregularly shaped and rigid, forming the shape of crescent moons. These altered cells result in reduced oxygen binding, decreased blood flow and can ultimately block the delivery of oxygenated blood to tissues.

Sickle cell disease is most commonly seen in individuals of African descent. Low bone density, severe infections and chronic musculoskeletal pain are some of the symptoms associated with SCD.

Current research has shown vitamin D deficiency (<30 ng/ml) is widespread among African American children with SCD, occurring in over 90% of patients. However, the potential role of daily vitamin D supplementation as a viable treatment option for SCD has not been tested.

A recent study conducted at the Children’s Hospital of Philadelphia aimed to determine the safety and effectiveness of daily vitamin D supplementation in children and young adults with SCD.

The researchers enrolled 22 African American’s with SCD and 22 healthy controls between the ages of 5 and 20. The participant’s anthropometrics, dietary intake and vitamin D status were assessed.

The researchers also measured biochemical and hematological markers for disease activity, including C-reactive protein and fetal hemoglobin. C-reactive protein (CRP) is a marker for general inflammation in the body. Fetal hemoglobin (HbF) levels indicate disease severity; HbF block the sickling action of red blood cells, therefore when HbF levels are higher, it typically indicates a more mild case of SCD.

Participants were randomly assigned a daily dose of 4,000 IU of vitamin D or 7,000 IU of vitamin D and evaluated at week 6 and week 12 for changes in their vitamin D status and SCD activity.

Here is what the researchers found:

  • At baseline, 95% of SCD cases and 87% of healthy controls had a suboptimal vitamin D status (<32 ng/ml).
  • When combined at baseline, 50% of these individuals considered to be deficient (<20 ng/ml).
  • Only 45% of the SCD group and 63% of the controls achieved vitamin D sufficiency as defined by vitamin D levels greater than 32 ng/ml, regardless of dosage.
  • At week 12, vitamin D deficiency was eliminated in all participants who received 7,000 IU of vitamin D daily.
  • For SCD participants in both dosage groups, there was a significant increase (p < 0.05) in HbF, decrease in CRP and a reduced percentage of individuals with an elevated platelet count.

The researchers concluded,

“Collectively, these findings suggest daily high-dose vitamin D supplementation of African American children and young adults with SCD and healthy subjects was safe, effective, and required to ensure no subject had deficient vitamin D status.”

There were a few limitations to note. The sample size was small, thereby decreasing the power of significance from the findings. Also, this was a controlled trial but not a randomized controlled trial.

The researchers call for large randomized double blind placebo controlled trials of high dose vitamin D to evaluate the potentially clinically significant outcomes of vitamin D supplementation in children and young adults with SCD.


Dougherty, K. et al. Safety and Efficacy of High-dose Daily Vitamin D3 Supplementation in Children and Young Adults With Sickle Cell Disease. J Pediatr Hematol Oncol, 2015.


  About: Missy Sturges

Missy is the Executive Director for the Vitamin D Council, and is responsible for overseeing the administration, programs and strategic planning of the organization. She also focuses on writing articles, fundraising and keeping up with the latest research. Her passion for vitamin D derives from her personal battle with an unexplained inflammatory disorder.