If you’re reading this, I’ve probably given this link to you, as a friend, after talking about the huge importance of getting enough Vitamin D. This is the first of many Vitamin D – related posts.
Vitamin D Deficiency – Don’t get the common cold!
The common cold, perhaps the most complained about “disease” in all of humanity. You can bet that modern day office worker has more colds than a paleolithic outdoors man did. In fact, if you can avoid a Vitamin D deficiency (and most people are deficient), one study shows that you reduce the number of colds you get in a year by 70%. So, if you normally get 10 colds per year, you could possibly only get 3 with proper Vitamin D levels. 
My experience in the first year of supplementing with Vitamin D confirmed this statistic for me. I did get 10 colds per year and I hated it (feeling bad, lost productivity, lost fun with the kids, etc). But, a year later I realized that I had had drastically fewer colds that year. And the couple colds that I did get only felt like they lasted a few days rather than a miserable 2-3 weeks. In the years since then, I have continued optimizing my Vitamin D levels and have continued having this drastically lower rate of colds.
Another study shows that the risk of respiratory infections goes up drastically as your levels of Vitamin D go down. At levels below 10ng/ml 24% of subjects reported a recent respiratory infection, whereas only 17% of respondents with levels 30ng/ml reported recent respiratory infections. That is a 41% increase in risk of respiratory infection if you are low on Vitamin D .
Vitamin D Deficiencies Suspected Causing Respiratory Infections in Children
Children benefit from proper Vitamin D levels too. An Indian study shows that children under the age of 5 are more than 3x as likely to get a respiratory infection when their Vitamin D levels are lower than 22.5 nmol/l versus above the same level .
I agree with Dr. Mercola (his newsletter) that good amounts of Vitamin D across the population are more powerful and more safe in fighting the flu than the flu shots are.
Are you Vitamin D Deficient?
Ok, so how many people are vitamin d deficient and how do I know if I am? 42% of adolescents according to one study , and many more depending on who you ask and at what level is considered “deficient.” This study considered anyone with levels below 20ng/ml to be Vitamin D deficient. Many others would suggest that you need 50ng/ml for optimal health and reducing colds. This post (blog post not released yet) shows who is deficient and by how much, but for now, go get your Vitamin D levels tested by your physician.
Sources of Vitamin D
A caveman would be out in the sun every day looking for food doing his hunting and gathering. Where do you spend most of your time? In a cubicle/office? Indoors at home? You are likely Vitamin D deficient.
Supplementation, may be next best thing to natural sunlight. Read (blog post not released yet) for more sources of Vitamin D.
Conclusion: Vitamin D deficiency could dramatically increase the number of colds your family gets this season.
 Association between serum 25-hydroxyvitamin D level and upper respiratory tract infection in the Third National Health and Nutrition Examination Survey. Arch Intern Med. 2009 Aug 10;169(15):1443.
 Wayse V, Yousafzai A, Mogale K, Filteau S. Association of subclinical vitamin D deficiency with severe acute lower respiratory infection in Indian children under 5 y. Eur J Clin Nutr. 2004 Apr;58(4):563-7.
 Prevalence of Vitamin D Deficiency Among Healthy Adolescents. Catherine M. Gordon, MD, MSc; Kerrin C. DePeter, BA; Henry A. Feldman, PhD; Estherann Grace, MD; S. Jean Emans, MD. Arch Pediatr Adolesc Med. 2004;158:531-537.