We’re heading into the Christmas holidays, where parties, friends, and family abound, and gifts and hugs are shared. Unfortunately, these close quarters are also prime opportunities for the flu and other viruses to be shared among us. If our immune systems are compromised with our lack of sunlight at this time of the year (and therefore low Vitamin D), and further taxed by lack of sleep, stress, alcohol, sweets, dry heated environments, and lack of exercise, we can be more susceptible to coming down with the flu.
So what’s the scoop on Vitamin D, and can it help you prevent and/or treat the flu?
Low Vitamin D levels are associated with higher flu rates.
There are many studies showing that deficient levels of Vitamin D are associated with higher rates of flus and respiratory tract infections. Now, keep in mind that just because there is a correlation, it doesn’t mean that the lack of Vitamin D is actually causing the increase in flus, and it’s definitely not the only factor. But clinically, we do see that optimizing Vitamin D levels and correcting deficiencies generally decreases patients’ frequency of getting sick with the flu.
Vitamin D supplementation has been studied in the context of preventing one kind of influenza, influenza A. It was found that supplementing with Vitamin D decreased influenza A flus in schoolchildren, with the added bonus of decreasing asthma rates in those susceptible (Urashima et al., 2010).
Optimize Your Vitamin D Levels
I frequently test my patients for their Vitamin D levels in the blood (25-0H Vitamin D), and very rarely are they adequate, even in those that are taking 1000-2000 IU of vitamin D on a daily basis! So often, if your levels were very deficient to start with, blindly taking the recommended intake won’t help very much. You also don't want to take too much and overdose!
The average blood level of Vitamin D in Canadians is below 75 nmol/L (the lower end of the “normal” range), and 1/3 of those people are likely quite deficient, with levels below 50 nmol/L. Levels in the winter are even lower than that! I aim not only for normal ranges, but optimal ranges for my patients. This usually requires prescription level doses of Vitamin D (>1000 IU a day), which I can prescribe. Getting your levels checked can allow me to dose your Vitamin D appropriately and safely, bringing your levels up quickly and efficiently. Vitamin D is also important for so many other things, including bone health, mood, and energy!
Treatment Of Flu With “The Vitamin D Hammer”
Most of us have come down with the flu at some point or another, and we know it can make us feel quite miserable. What if you could cut that misery short? Can Vitamin D help once you already have the flu?
There isn’t much research in the area. However, there is some evidence clinically from doctors who use high doses of Vitamin D that it can be very helpful. We’re not talking about 800-1000 IU a day in these instances, as this likely would be too little, too late for most people. Dr. Gerry Schwalfenberg, MD, and his colleague use very high doses of Vitamin D (we’re talking high prescription doses) at the onset of the flu for 2-3 days. They call this “the Vitamin D hammer”, flooding the body with Vitamin D short-term! With this protocol, they find that patients’ symptoms resolve within 48-72 hours, which is amazing considering that the usual flu will often last a week or more, and can be followed by feeling weak and rundown for a while still afterwards.
Do you want to minimize your chances of getting the flu? Then among your arsenal, a good personalized dose of Vitamin D would probably be a good idea. We can get you tested to optimize your levels, and include other immune-boosting measures and supplements into your treatment plan so that you keep up your energy and smile all winter long!
Schwalfenberg G. (2015). Vitamin D for influenza. Can Fam Physician, 2015 Jun; 61(6):507. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4463890/
Urashima M., Segawa T., Okazaki M., Kurihara M., Wada Y., and Ida H. (2010). Randomized trial of vitamin D supplementation to prevent seasonal influenza A in schoolchildren. Am J Clin Nutr, 2010 May;91(5):1255-60. doi: 10.3945/ajcn.2009.29094. Epub 2010 Mar 10.
We will soon be heading back into the cold and flu season in Canada, which usually begins around November and ends in April. While limiting exposure to the viruses associated with these respiratory tract infections is indeed important, making sure that your immune system is in top shape to quickly and effectively clear any infectious microbes it encounters is the best way to prevent a full-blown illness. If you tend to get sick frequently during the winter months, now is a good time to make sure that your immune system is working at its best. Vitamin D3 is one of your key tools for helping you fight off these microbes.
Vitamin D exists in our body in an inactive form, and it only transforms into its active, vitamin D3 form if our skin is exposed to sunlight. Needless to say, this is difficult to do in the winter, and most Canadians are deficient in vitamin D3 unless they supplement with the active form throughout the fall and winter months. Vitamin D3 has been shown to activate the innate immune response and leads to the production of antimicrobial peptides (called cathelicidin and defensins) which help fight off viruses and secondary bacterial infections. Adequate vitamin D3 levels have been associated with a decreased risk of influenza and other respiratory tract infections. One study even showed that this decreased risk is passed on from pregnant mothers to their children for their first year of life.
One way to check if you have enough vitamin D is through a blood test, serum 25(OH)D. While levels above 50nmol/l are generally considered sufficient, many experts in the field believe that levels of 100nmol/l or higher are more optimal. Studies so far have shown that those who were most deficient prior to vitamin D3 supplementation gained the most anti-viral protective effects. Darker skinned individuals, who tend to produce less active vitamin D3 when exposed to the sun, are especially prone to being deficient during the winter months.
Although vitamin D3 status plays a powerful role in immunity, it is far from the only variable affecting our defenses against colds and flus. Naturopathic doctors have many other preventative treatments available, and can individualize your treatment protocol based on your health status, unique susceptibilities, current medications, diet, and lifestyle.
Am J Clin Nutr May 2010 vol. 91 no. 5:1255-1260.
Epidemiology. 2012 Jan;23(1):64-71.
Int J Infect Dis. 2010 Dec;14(12):e1099-105. Epub 2010 Oct 29.
J Clin Virol. 2011 Mar;50(3):194-200. Epub 2011 Jan 15.
Dr. Tamar Ferreira is a Naturopathic Doctor in Brampton, Ontario. Her areas of focus include digestive health, hormone balance, and skin conditions.