An article published in the February 23, 2009 issue of the American Medical Association journal Archives of Internal Medicine revealed an association between lower levels of serum vitamin D and decreased resistance to upper respiratory tract infection (URTI), otherwise known as the common cold.
Researchers at Massachusetts General Hospital, Children's Hospital, Boston, and the University of Colorado analyzed data from 18,883 participants in the Third National Health and Nutrition Examination Survey (NHANES III) of U.S. participants aged 12 and older. Physical examinations following enrollment obtained blood samples and information including the occurrence of recent upper respiratory tract infections. Stored blood samples were analyzed for serum 25-hydroxyvitamin D levels.
Nineteen percent of the participants reported having a recent cold. For those whose serum vitamin D levels were lower than 10 nanograms per milliliter, the incidence was 24 percent, for subjects whose levels were 10 to less than 30 ng/mL the incidence was 20 percent, and the rate dropped to 17 percent among those with levels of 30 ng/mL or higher. After adjustment for demographic and other characteristics, those whose vitamin D levels were lowest experienced a 36 greater risk of URTI, and those whose levels were 10 to less than 30 ng/mL experienced a 24 percent greater risk compared with participants whose levels were at least 30 ng/mL. The association was significantly stronger for those with asthma.
The study is the largest and most nationally representative of its kind to date. “To our knowledge, this is the first population-based study to evaluate and demonstrate an association between serum 25-hydroxyvitamin D level and URTI,” the authors remark.
"The findings of our study support an important role for vitamin D in prevention of common respiratory infections, such as colds and the flu," concluded lead author Adit Ginde, MD, MPH, of the University of Colorado Denver Division of Emergency Medicine. "Individuals with common lung diseases, such as asthma or emphysema, may be particularly susceptible to respiratory infections from vitamin D deficiency."
"A respiratory infection in someone with otherwise healthy lungs usually causes a few days of relatively mild symptoms," explained senior author Carlos Camargo, MD, DrPH, of the Massachusetts General Hospital Department of Emergency Medicine. "But respiratory infections in individuals with an underlying lung disease can cause serious attacks of asthma or COPD that may require urgent office visits, emergency department visits or hospitalizations. So the impact of preventing infections in these patients could be very large."
"We are planning clinical trials to test the effectiveness of vitamin D to boost immunity and fight respiratory infection, with a focus on individuals with asthma and COPD, as well as children and older adults -- groups that are at higher risk for more severe illness," Dr Ginde added. "While it's too early to make any definitive recommendations, many Americans also need more vitamin D for its bone and general health benefits. Clinicians and laypeople should stay tuned as this exciting area of research continues to expand."Related Health Concern: Common Cold
Although there is no cure for the common cold, patients should be proactive even before symptoms first appear to prevent infection, recover more quickly, reduce the severity of symptoms, and prevent the spread of the contagion. Frequent hand-washing and use of facial tissues with antiviral agents will help prevent the spread of the infection. In addition, take the following steps (especially during cold season):
- Eat properly.
- Get plenty of rest.
- Drink at least 8 to 10 glasses of fluids a day to avoid dehydration, keep mucous membranes moist, and loosen mucus.
- Abstain from alcohol because it reduces the body's ability to fight infection.
- Avoid smoking and smoky places.
- Use mild pain relievers with anti-inflammatory properties, such as ibuprofen, to reduce aches and pains.
- Use saline-based, over-the-counter nose drops to relieve a stuffy nose.
- Use a cool-mist humidifier to keep nasal passages moist. Change the water daily to avoid buildup of molds.
A number of nutrients should also be considered, beginning when symptoms first appear, or when exposure to cold viruses is elevated (for example, when a member of the household is sick). These nutrients include:
- Vitamin C--1 to 10 grams (g) daily, in divided doses, up to bowel tolerance
- Zinc gluconate--one lozenge (5 to 15 mg) every 2 hours (while awake)
- A. membranaceus--300 mg a day or 4 to 7 g in powder form
- N-acetyl cysteine--600 mg two times daily with vitamin C
- Melatonin--10 mg/day 30 to 60 minutes before bed
- Garlic extract--600 to 1200 mg/day
- A. paniculata--400 mg three times daily; for prevention, 200 mg/day 5 days a week
- Lactoferrin--300 to 900 mg/day