New Research proves Vitamin-D to protect from Respiratory Infections
This article is written in simple form from the new study published in the british medical journal on 15th feb 2017.
23 Researchers conducted Randomized control trials in 14 countries on four continents and enrolled total 11 321 participants, aged 0 to 95 years out of which Individual participant data(IPD) of 10933 was collected and found that Vitamin D supplementation reduced the risk of acute respiratory tract infection among all participants.
BACKGROUND
What is vitamin D?
Vitamin D are group of fat-soluble steroidal hormones that help in absorption of calcium,iron,zinc, phosphate and magnesium. Two important group of vitamin D are vitamin D3 (also known as cholecalciferol) and vitamin D2 (ergocalciferol).Vitamin- D2 and D3 can be ingested from the diet and from supplements. It is synthesized in body in liver and kidney. Dermal synthesis of vitamin D from cholesterol is dependent on sun exposure (specifically UVB radiation).
Recommended serum levels of Vitamin D: 75 nmol/l
The Research
Acute respiratory tract infections are a major cause of global morbidity and mortality and around the Globe. An estimated 2.65 million deaths occurred worldwide in 2013 due to ART.
The study:
25-hydroxyvitamin D supports induction of antimicrobial peptides in response to both viral and bacterial infection.
Vitamin D metabolites have also been reported to induce innate antimicrobial effector mechanisms, including induction of autophagy and synthesis of reactive nitrogen intermediates and reactive oxygen intermediates
Previous studies have reported role of Vit D in decreasing the infection but some have not been statistically significant. There results were different from each other due to Dosing of Vit D and Participant variability.
To rule out this variability and dosing errors they undertook an IPD meta-analysis based on all 25 randomized controlled trials of vitamin D supplementation for prevention of acute respiratory tract infection that were completed up to the end of December 2015.
A group of 25 Randomised control Study was done which was Double blind( Neither doctor or Patients knew about study) to remove bias. Various subgroups were formed in study to remove the Bias from hetrogenicity and dosing of Vit D.
Final results
1.Meta-analysis of IPD from 10 933 participants in 25 randomised controlled trials showed an overall protective effect of vitamin D supplementation against acute respiratory tract infection.
2.Benefit was greater in those receiving daily or weekly vitamin D without additional bolus doses. The protective effects against acute respiratory tract infection in this group were strongest in those with severe vitamin D deficiency at baseline(75nmol/l)
3.Study recommended food fortification with Vit D to improve Vit D nutrition status in public.
References:
https://en.wikipedia.org/wiki/Vitamin_D
http://www.bmj.com/content/356/bmj.i6583