Vitamin D supplements could help keep winter coughs and colds away, according to a new study.
Researchers from Queen Mary University in London said the vitamin could help prevent acute respiratory tract infections – particularly among people with vitamin D deficiencies.
They said their findings, published in the BMJ, support the introduction of public health measures such as food fortification to boost the nation’s vitamin D intake.
Vitamin D is essential for controlling the amount of calcium and phosphate in your body, which keep bones, teeth and muscles healthy.
Last year, Public Health England said that people were not getting the recommended 10 micrograms of vitamin D a day from sunlight in winter, and advised members of the public to take vitamin D supplements or eat foods rich in the vitamin to improve health.
Not only can vitamin D boost bone health, but it can also help stave off winter respiratory infections, according to new research.
Acute respiratory tract infections are a major cause of global illness and death. They can include anything from the common cold to bronchitis and pneumonia and have been linked with low blood levels of vitamin D.
Some studies have shown that vitamin D can trigger immune responses to certain bacteria and viruses, but randomised trials of vitamin D supplements to prevent acute respiratory tract infection have led to conflicting results.
An international team of researchers set out to assess the overall effect of vitamin D supplements on preventing acute respiratory tract infection.
They conducted a review of data from 25 randomised controlled trials of vitamin D supplementation, involving 11,321 participants aged 0 to 95 years.
They found that vitamin D supplementation resulted in a 12% reduction in the proportion of participants experiencing at least one acute respiratory tract infection.
Further analyses showed benefit was greater in those receiving daily or weekly vitamin D without additional large (bolus) doses.
The researchers point to some study limitations, including limited power to detect effects of vitamin D for some groups. However they concluded: “Our results add to the body of evidence supporting the introduction of public health measures such as food fortification to improve vitamin D status, particularly in settings where profound vitamin D deficiency is common.”
In a linked editorial, Mark Bolland from the University of Auckland and Alison Avenell from the University of Aberdeen, questioned whether the results were a major new development.
They pointed to several methodological flaws with the study and argued that the results are “not sufficiently applicable to the general population”.
“Current evidence does not support the use of vitamin D supplementation to prevent disease, except for those at high risk of osteomalacia (weak bones and muscles due to low blood vitamin D levels, currently defined as less than 25 nmol/L)”, they concluded.
Professor Louis Levy, head of nutrition science at Public Health England, said: “Based on evidence reviewed by the Scientific Advisory Committee on Nutrition (SACN), we recommend that certain population groups take a daily 10 micrograms Vitamin D supplement year round and everyone considers taking one during the autumn and winter months to protect musculoskeletal health.
“The evidence on Vitamin D and infection is inconsistent and this study does not provide sufficient evidence to support recommending Vitamin D for reducing the risk of respiratory tract infections.”