Vitamin D, “the sunshine vitamin,” may very well be one of the most beneficial vitamins there is for disease prevention. Unfortunately it’s also one of the vitamins that a vast majority of people across the world are deficient in due to lack of regular exposure to sunshine.
Published in the journal Epidemiology and Infection in 2006, the hypothesis presented by Dr. John Cannell and colleagues in the paper Epidemic Influenza and Vitamin D raises the possibility that influenza is a symptom of vitamin D deficiency.
The vitamin D formed when your skin is exposed to sunlight regulates the expression of more than 2,000 genes throughout your body, including ones that influence your immune system to attack and destroy bacteria and viruses. Hence, being overwhelmed by the “flu bug” could signal that your vitamin D levels are too low, allowing the flu virus to overtake your immune system.
At least five studies show an inverse association between lower respiratory tract infections and 25(OH)D levels. That is, the higher your vitamin D level, the lower your risk of contracting colds, flu, and other respiratory tract infections:
- A 2007 study suggests higher vitamin D status enhances your immunity to microbial infections. They found that subjects with vitamin D deficiency had significantly more days of absence from work due to respiratory infection than did control subjects.
- A 2009 study on vitamin D deficiency in newborns with acute lower respiratory infection (ALRI) confirmed a strong, positive correlation between newborns’ and mother’s vitamin D levels. Over 87 percent of all newborns and over 67 percent of all mothers had vitamin D levels lower than 20 ng/ml, which is a severe deficiency state.
Newborns with vitamin D deficiency appear to have an increased risk of developing ALRI, and since the child’s vitamin D level strongly correlates with its mother’s, the researchers recommend that all mothers’ optimize their vitamin D levels during pregnancy, especially in the winter months, to safeguard their baby’s health.
- A similar Indian study published in 2004 also reported that vitamin D deficiency in infants significantly raised their odds ratio for having severe ALRI.
- A 2009 analysis of the Third National Health and Nutrition Examination Survey examined the association between vitamin D levels and recent upper respiratory tract infection (URTI) in nearly 19,000 subjects over the age of 12.
Recent URTI was reported by:
- 17 percent of participants with vitamin D levels of 30ng/ml or higher
- 20 percent of participants with vitamin D levels between 10-30 ng/ml.
- 24 percent of participants with vitamin D levels below 10ng/ml
The positive correlation between lower vitamin D levels and increased risk of URTI was even stronger in individuals with asthma and chronic obstructive pulmonary disease.
- Another 2009 report in the journal Pediatric Research stated that infants and children appear more susceptible to viral rather than bacterial infections when deficient in vitamin D. And that, based on the available evidence showing a strong connection between vitamin D, infections, and immune function in children, vitamin D supplementation may be a valuable therapy in pediatric medicine.