We usually think of vitamin D in connection with strong bones but the benefits of vitamin D appear to be much more far-reaching. A new study shows that vitamin D can support the immune system and help prevent colds and flu.
Researchers teamed up to conduct a large national study on Vitamin D and respiratory infections. Investigators researched the benefits of vitamin D from several locations: the University of Colorado Denver, Massachusetts General Hospital and Children’s Hospital Boston.
The resulting study, published in the Archives of Internal Medicine, was the largest and most representative of the U.S. population done on the connection between vitamin D and immunity.
Results showed that people with the lowest levels of vitamin D in their blood had significantly more cases of cold and flu. Risks were even higher among those who have chronic respiratory problems like asthma and emphysema. Low levels of vitamin D made them particularly susceptible. (1)
Vitamin D Deficiency Symptoms Can Be Subtle
You may be inclined to take some extra vitamin C to protect against colds, but evidence is building that vitamin D plays an important role as well. It makes sense when you think about it. Cold and flu season is during the winter months – just when natural vitamin D levels are lower. The “sunshine” vitamin is in shorter supply, highlighting the effect of vitamin D deficiency symptoms.
Well known vitamin D deficiency symptoms are rickets in children (lack of bone mineralization leading to deformities), and osteomalacia – a similar condition in adults.
Other symptoms are more subtle… muscle aches, muscle weakness and bone pain. These conditions may not be severe at first and don’t necessarily cause you to think of vitamin D deficiency symptoms – but they just might be.(2)
Foods With Vitamin D Versus Sunshine
Besides sun exposure, vitamin D is present in food. Foods with vitamin D include dairy products like cheese, butter and cream. Also fish, fish liver oils, egg yolks, oysters and margarine.
Unfortunately, it is hard to raise blood levels of vitamin D with diet alone, so many foods are fortified with vitamin D to boost dietary levels. All milk in the United States is fortified with vitamin D as are a lot of cereals and grain products to make it easier for you to get the benefits of vitamin D.
Since it is hard to get what you need from foods with vitamin D, sunshine remains the best natural source. 10-15 minutes of sun exposure, three times a week, is recommended as a minimum. And that’s without sunscreen – which inhibits vitamin D production.
Getting even this amount of sun might be a challenge in the winter in northern climates or for seniors who may be housebound. And believe it or not, it’s becoming a concern for children who spend more time secluded with television and computers than playing outside.
More Reasons for Vitamin D Deficiency Symptoms
Besides lack of sun exposure and eating enough foods with vitamin D, a few other things can come into play. For instance:
A strict vegetarian diet – most food sources of vitamin D are animal based
Milk allergies – dairy products are a common source of vitamin D
Dark skin – more melanin in the skin reduces its ability to make vitamin D from sunlight
Aging – as people age, their kidneys become less able to convert vitamin D to the usable form in the body
Obesity – vitamin D is absorbed from the blood into fat cells, but those with a body mass index of 30 or higher tend to have lower levels of vitamin D
Digestive disorders – if the ability of the intestines to absorb is compromised, the benefits of vitamin D are lost. This happens in Crohn’s disease, celiac disease, cystic fibrosis and malabsorption disorders. (3)
All of these factors together make for a population that is suffering from vitamin D deficiency.
Better Immunity Means Fewer Respiratory Problems
As new studies are revealing, the benefits of vitamin D include better immunity. A survey conducted by the National Center for Health Statistics polled almost 19,000 adults and adolescents. It involved a physical exam and blood analysis.
Those who had the lowest levels of vitamin D – less than 10 nanograms per milliliter of blood – were 40% more likely to have had a respiratory infection than those whose level of vitamin D was 30ng/ml or higher. This held true year round, regardless of traditional cold and flu season.
Patients with cardio obstructive pulmonary disease (COPD) who were deficient in vitamin D had twice as many respiratory infections. Asthma patients with low vitamin D fared the worst – they had five times as many respiratory infections.
Dr. Carlos Camargo, senior author of the study, pointed out, “A respiratory infection in someone with otherwise healthy lungs usually causes a few days of relatively mild symptoms, 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.” (4)
Boost your own immunity with a little sunshine – in moderation – to take advantage of the benefits of vitamin D.
Before you make any changes to your own diet, exercise or supplement routine, please consult with your personal physician.
Sources:
Ginde AA, Liu MC, Camargo CA, Demographic Differences and Trends of Vitamin D Insufficiency in the US Population, 1988-2004, Arch Intern Med. 2009;169(6):626-632
Vogin G, “Vitamin D Deficiency,” WebMD.com, July 13, 2009
Vogin G, “Vitamin D Deficiency,” WebMD.com, July 13, 2009
“Vitamin D Boosts Immunity, Prevents Colds, Flu: Study,” MedIndia.net, Feb 24, 2009
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