Vitamin D is normally known for its “healthy” effects on bones and teeth, but thanks to a new study published in BMJ, Vitamin D can prevent acute respiratory tract infections safely and efficaciously.
The scientists included all placebo-controlled, double blind random trials with vitamin D2 or Vitamin d3 supplements. The main outcome measurement, the scientists looked for was data on frequency of acute respiratory tract infections.
A total of 25 trials of this nature were conducted, which included more than a cumulative of 11000 patients. The results showed that vitamin D decreased acute respiratory tract infection risks in all patients.
Moreover, among the subgroups of patients who received non-bolus weekly or daily doses of Vitamin D had shown protective effects, but these effects were not present in individuals who took one or two bolus doses.
Overall the stats showed that patients who had sever vitamin D deficiency and who did not consume bolus doses showed the most significant response and had benefitted the most.
This study comes at a great time as acute respiratory tract infections still remain a major health concern. 10% of all emergency and ambulatory calls and responses in the US were made as a result of this and close to 2.7 million deaths occurred in 2013 globally due to acute respiratory tract infections.
Previous studies have shown that low serum concentrations of 25-hydroxyvitamin D improves respiratory tract health. This effect comes largely due to the ability of 25-hydroxyvitamin D to enhance immune response to both viral and bacterial stimuli.
Clinical data has also shown that vitamin D helps fight free radicals and respiratory pathogens while also promoting natural cell death, so body’s natural defence systems stays on alert and active at all times.
Given the surmountable evidence in favour of vitamin D’s potential health benefits, there have been several studies, a majority of which show the protective effects of vitamin D on respiratory health and in its ability to protect against acute respiratory tract infections.
Few studies which could not establish a link between vitamin D and its ability to fight acute respiratory tract infections, may have altered the dose, or did not properly consider the trial participants’ characteristics, according to authors of the current study.
Moreover the authors suggest that participant’s age status and body mass index might also influence the results. Large vitamin doses’ diminished health benefits did not surprise the scientists, as similar effects were observed in previous studies.
The reason for large doses of vitamin D being inefficient and ineffective at controlling symptoms of acute respiratory tract infections is that high circulating concentrations of 25-hydroxyvitamin D interferes with vitamin D metabolizing enzymes which makes their availability limited.
This effect overall reduces the efficiency of vitamin D to promote timely immune response.
Another factor needed to be considered is if patients suffered from any other disease, since patients suffering from chronic obstructive pulmonary disease who had low Vitamin D levels responded better to the supplements and showed significant health benefits.
So why are acute respiratory infections such a big deal that they require vitamin D supplements to fight them off.
Acute respiratory infections hinder the proper functioning of the respiratory system due to a bacterial or viral infection in the upper respiratory tract, in the lungs or bronchial tubes.
The infections include bronchitis, influenza, pneumonia, asthma among several others and can be fatal in people with compromised immune systems such as kids or old people. Vitamin D deficiency can easily lead to a weak immune system causing bronchitis, asthma, and influenza.
Moreover kids suffering from influenza during winters are given extra dose of vitamin D to provide relief, due to lack of sunlight. As kids who are at greater risk of developing vitamin D deficiency during colder periods of the year, this is not at all a bad idea.
Regular consumption of vitamin D has other benefits as well. vitamin D can improve physical performance and reduce the risk of cardiovascular diseases by decreasing blood pressure and lowering stress hormone levels such as cortisol.
Additionally, sufficient vitamin D levels help in regulating phosphate and calcium in the blood which is essential to healthy bone and teeth formation.
Almost all of the American milk supply is enriched with high dose of vitamin D in each cup of milk. Other sources of vitamin D include fish like mackerel, tuna and salmon, beef liver, dairy products such as yogurt, eggs and cheese. A few breeds of mushrooms also contain vitamin D.
Some people meet their requirements of vitamin D through sunlight. When ultraviolet radiation penetrates skin layers, it converts 7-dehydrocholesterol to previtamin D3, which later on transforms to vitamin D3.
How much vitamin D is synthesized in the body through sunlight exposure depends on factors such time and length of the day, season, how clear or cloudy the skies are and skin’s melanin content.