(Relaxnews) – A new study published Wednesday finds no evidence that taking vitamin D supplements can help keep colds at bay.
While prior studies have suggested that vitamin D plays a role in the body’s immune system, a team from New Zealand did the "gold standard" of tests, according to the BBC, which means a randomized placebo-controlled trial, to see if supplements of the vitamin had any impact on colds.
The researchers from the University of Otago in Christchurch assigned 322 healthy adults to take either vitamin D supplements or a placebo once a month for 18 months. Participants received either an initial dose of 200,000 IU oral vitamin D, then 200,000 IU one month later, or a placebo administered in an identical dosing regimen.
As reported in the Journal of the American Medical Association, by the end of the study, both groups averaged just under four upper respiratory tract infections each, with symptoms lasting an average of 12 days in both groups.
According to the BBC, adults catch between two and four colds a year and children up to 10 a year.
While humans mostly get vitamin D from sunlight on skin, vitamin D does occur naturally in certain foods, such as oily fish like salmon and sardines.