03 October 2012

Study Show No Connection Between Vitamin D Levels and Upper Respiratory Tract Infections Such As The Common Cold

Vitamin D is a vitamin that can be synthesized (created) by the body through exposure to sunlight. It helps regulate the calcium and phosphate levels in the body. It also helps keeps bones and teeth healthy.

Despite it being available through sunlight, studies has shown that people still suffer from vitamin D deficiency. Lack of vitamin D can lead to diseases such as rickets, osteomalacia, and bone deformities.

Vitamin D deficiency is said to occur because of the promoted use of sunscreen which blocks the levels of sunlight needed by the body to create the vitamin. Changing lifestyles where people tend to stay indoors more is also a factor.

Some countries such as Australia have already encouraged people to get the right amount of sunshine. According to Dr. Michael Holick, who is a well known specialist on vitamin D, suggests a daily 5 to 15 minute exposure to sunlight between 9am to 3pm is optimal. Care must be taken since overexposure to sunlight is also dangerous to the body.

According to Dr. Holick, treatments for diseases such as psoriasis, Parkinson's and cancer can benefit from having vitamin D at optimum levels. Also, because of the amount of sunlight that is reduced during winter which results in lowered production of vitamin D in the body, it was believed that vitamin D may be a factor in upper respiratory tract infections like the common cold.

Aside from sunlight, Vitamin D is also present in some foods such as oily fish (salmon), eggs, breakfast cereals, and milk.

The featured video below is highly recommended to understand more about vitamin D and its importance to the body.

Vitamin D supplementation does not reduce rate or severity of colds

Although some data have suggested a possible inverse association between serum vitamin D levels and the incidence of upper respiratory tract infections (colds), participants in a randomized controlled trial who received a monthly dose of 100,000 IUs of vitamin D3 did not have a significantly reduced incidence or severity of colds, according to a study in the October 3 issue of JAMA.

The association of vitamin D insufficiency and susceptibility to viral respiratory tract infections has been unclear, according to background information in the article.

Video: Vitamin D and Prevention of Chronic Diseases

David R. Murdoch, M.D., of the University of Otago, Christchurch, New Zealand, and colleagues conducted a randomized trial to examine the effect of vitamin D supplementation on incidence and severity of upper respiratory tract infections (URTIs) in healthy adults. The study, conducted between February 2010 and November 2011, included 322 healthy adults in New Zealand. Participants were randomly assigned to receive an initial dose of 200,000 IU oral vitamin D3, then 200,000 IU one month later, then 100,000 IU monthly (n = 161), or placebo administered in an identical dosing regimen (n = 161), for a total of 18 months.

The average 25-hydroxyvitamin D (25-OHD) level of participants at the beginning of the study was 29 ng/mL. Vitamin D supplementation resulted in an increase in serum 25-OHD levels that was maintained at greater than 48 ng/mL throughout the study. There were 593 URTI episodes in the vitamin D group and 611 in the placebo group.

The researchers found that there was no statistically significant differences in the number of URTIs per participant (average, 3.7 per person in the vitamin D group and 3.8 per person in the placebo group), duration of symptoms per episode (average, 12 days in each group), number of days of missed work as a result of URTIs, or severity of URTI episodes.

"The main finding from this study is that a monthly dose of 100,000 IU of vitamin D3 in healthy adults did not significantly reduce the incidence or severity of URTIs. This result remained unchanged when the analysis included winter season or baseline 25-OHD levels," the authors write. "Further research is required to clarify whether there is benefit from supplementation in other populations and with other dosing regimens."


JAMA and Archives Journals
University of Otago, Christchurch (UOC)
Michael F. Holick, Ph.D., M.D.
Vitamin D Deficiency Linked To High Mortality Rates in Nursing Home Residents
High Doses of Vitamin D Stimulates Recovery In Patients With Tuberculosis
High Sun Exposure Lowers Risk For Pancreatic Cancer
Drinking Alcohol Decreases Risk of Osteoporosis
Osteoporosis Medication May Cause Serious Eye Disease
Developments in More Effective Leprosy Therapies
Milk Ingredient, Nicotinamide Riboside, Protects Against Obesity
Milk and It's Effect on Brain Development and Performance