Vitamin D: The Key To Beating Colds & Flu?

A recently published scientific review states that supplementing food with vitamin D would prevent millions of cold and flu cases, and possibly save lives. The meta-analysis suggests daily or weekly vitamin D supplementation was useful in preventing respiratory tract infections.


A recent meta-analysis of data regarding the supplementation food with vitamin D, has found that fortifying our diet, by adding Vitamin D to our food, it would be possible to prevent millions of cold & flu cases, and save lives.  The researchers looked at data from 25 studies, analyzing data of over 11,000 participants, in which vitamin D was compared with a placebo.  The studies explored the effect of vitamin D in preventing acute respiratory tract infections.  An acute respiratory infection is an infection of the body’s airways, such as colds & flu, bronchitis, and pneumonia.

The team behind the meta-analysis suggests daily or weekly vitamin D supplementation is useful in preventing acute respiratory tract infections, with supplementation being particularly beneficial for those with low levels of vitamin D. The researchers concluded that these results add to the growing body of evidence that fortifying widely eaten foods with vitamins would greatly improve public health.


“daily or weekly vitamin D supplementation is useful in preventing acute respiratory tract infections”


The Research Method

This systematic review and meta-analysis investigated the use of vitamin D supplementation as a way of preventing acute respiratory tract infections such as flu, bronchitis and pneumonia. The research teams searched four literature databases and two clinical trial registries to identify Randomized Clinical Trials that looked at the overall effect of vitamin D supplementation on risk of acute respiratory tract infection. To be included in the review, studies had to compare vitamin D3 or D2 with placebo pill.  They also had to be double blind studies, in order to be included within their analysis, meaning that neither the participant nor the doctor knew which pill was administered.  The trials had to set out to look at the rates of respiratory infections within the participants.

The studies included in the analysis were all considered to be high quality according to Cochrane risk of bias tool, which assesses bias and skewed reporting. When analyzing the collected data, the researchers adjusted for the potential confounding effects of age, sex and duration of the study.

They also performed subgroup analyses, where a data set is split into smaller groups to check for possible patterns, to determine if other factors such as asthma and body mass index affected the results.

In total, 25 Randomized Clinical Trials from 14 countries were included, involving a total of 11,321 participants, aged from 0-95 years.

vit-d-pic-1


“25 randomized clinical trials from 14 countries were included, involving a total of 11,321 participants”


Findings

After pooling the findings, the research teams found that vitamin D supplementation was observed to reduce the risk of acute respiratory tract infection by 12%.

When splitting the participants into smaller subgroups, a statistically significant protective effect was observed for those participants who had daily or weekly vitamin D supplementation, without large one-off doses, but not for those receiving one or more large one-off doses. Among those receiving daily or weekly vitamin D, protective effects were stronger for those with lower vitamin D levels at the start of the study and participants suffering from asthma.  It was observed that there were no serious adverse side effects or deaths linked to supplementation.


“a statistically significant protective effect was observed for those participants who had daily or weekly vitamin D supplementation”


What Can We Conclude?

The researchers concluded that the study reports an indication for vitamin D supplementation in order to facilitate the prevention of acute respiratory tract infection, and that those who are deficient in vitamin D experienced particular benefit from supplementation. The research teams state that their results add to the body of evidence supporting the introduction of public health measures such as food fortification to improve vitamin D levels across the population, particularly in cases where profound vitamin D deficiency is highly common.

vit-d-pic-2


“indication for vitamin D supplementation in order to facilitate the prevention of acute respiratory tract infection”


Who Carried Out The Research?

The study was carried out by researchers from a number of institutions, including Queen Mary University, Winthrop University Hospital and the Karolinska Institutet, and no manufacturers of vitamin D supplements were involved in this research. Funding was provided by the National Institute for Health Research. The study was published in the peer-reviewed British Medical Journal.

The British Medical Journal itself includes an editorial from independent experts arguing that food should not be routinely fortified with vitamin D.


“The British Medical Journal itself … independent experts … arguing that food should not be routinely fortified with vitamin D”


Author : Amanpreet Singh Grewal

Article: http://www.bmj.com/content/356/bmj.i6583

Images taken from the CreativeCommons

Comments are closed.