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Study suggests high dose vitamin D supplementation improves markers of systemic inflammation

Posted on: May 26, 2017   by  Missy Sturges & John Canell, MD


A recent cohort study published by the Journal of Cellular Biochemistry found that high dose vitamin D supplementation decreased markers of systemic inflammation among adolescent girls.

Adolescence marks a critical stage of development. Therefore, proper nutrition and exercise are particularly important during this time. With the abundance of research continuing to stress the importance of vitamin D screening and treatment of deficiency to protect the health of adolescents, the medical community has slowly begun taking action. In recent years, vitamin D testing has increased significantly. As a result, the number of children diagnosed with vitamin D deficiency has increased by 15-fold over the last 10 years.

Childhood vitamin D deficiency is associated with developmental delays, a compromised immune system, neurological function and inflammation. When inflammation becomes chronic, individuals become more susceptible to hypertension, heart disease and stroke in adulthood.

In order to protect future generations from the life-threatening chronic health conditions that are currently plaguing the adult population, preventive action must be implemented early in life. Unfortunately, much debate remains regarding the approach to treating vitamin D deficiency during childhood. Additionally, it is difficult to quantify the clinical improvements vitamin D produces when a disease state is not present.

In a recent cohort study conducted in Mashhad, Iran, researchers aimed to determine whether high dose vitamin D supplementation affected indicators of inflammation in the body, including C-reactive protein (CRP) and neutrophil to lymphocyte ratio (NLR) among adolescent girls. Neutrophils and lymphocytes are types of white blood cells fundamentally important in the immune system, with elevated levels indicating the presence of inflammation or infection.

Those with a history of chronic illness, recent fractures, hypersensitivity to vitamin D or who were pregnant or lactating were excluded from the study.

A total of 580 girls between the ages of 12-18 years were included in the study. At baseline, the participants’ height and weight were recorded. They also received a lab analysis and were given 50,000 IU vitamin D3 on a weekly basis. After 3 months, the participants’ height, weight and blood work parameters were recorded again.

Here is what the researchers found:

  • The mean age, weight and BMI of the participants were 14.5±1.5 years, 52.8±12.0 kg, and 21.2±4.3 kg/m2, respectively.
  • The participant’s average 25(OH)D status increased from 9.4 ng/ml at baseline to 36.4 ng/ml after 3 months of supplementation (p < 0.001).
  • Serum CRP significantly dropped from 0.9 at baseline to 0.8 after 3 months of supplementation (p = 0.007).
  • NLR decreased from 1.66 at baseline to 1.53 after 3 months (p = 0.002).
  • Vitamin D supplementation was associated with a significant decrease in neutrophil count (p < 0.001).
  • Weight and BMI were significantly associated with CRP quartiles (p < 0.001).
  • CRP was associated with triglyceride levels (p < 0.001), white blood cell count and lymphocytes (p = 0.001).

The researchers concluded,

“To the best of our knowledge this is the first study showing that high-dose supplementation of vitamin D affects measures of systemic inflammation: reductions in High-Sensitivity C-Reactive Protein level and Neutrophil to lymphocyte ratio (NLR) distribution in a large population of adolescent girls.”

As always, it is important to note the study’s strengths and limitations. The researchers included a large sample size, provided adequate supplement doses and accounted for several confounding factors. However, the lack of a control group makes it impossible to definitively state that vitamin D decreases systemic inflammation among adolescent girls.

Therefore, the researchers called for randomized controlled trials, the gold standard in research, to confirm their findings and gain further understanding of the role vitamin D plays in inflammation.


Sturges, M. & Cannell, JJ. Study suggests high dose vitamin D supplementation improves markers of systemic inflammation. The Vitamin D Council Blog & Newsletter, 5/1017.


Tabatabaeizadeh SA, et al. High-dose supplementation of vitamin D affects measures of systemic inflammation: reductions in High-Sensitivity C-Reactive Protein level and Neutrophil to lymphocyte ratio (NLR) distribution. J Cell Biochem, 2017.

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