Post by Emily White
The average person gets struck down with a cold or flu two to three times every year. It is estimated to be one of the most frequent illnesses amongst humans and brings about great frustration, as it seems your body waits until it is absolutely most inconvenient before you get struck down with the virus. Murphy's law right?!
With the changing seasons, it seems most appropriate to address the current research around the common cold and ways to reduce severity or susceptibility. Research is suggesting that vitamin D plays a role in immunity and susceptibility to infection. This makes sense when you think about it, that as winter comes and the temperature drops, we spend less time in the sun and more time indoors. This results in a significantly decreased level of vitamin D in the winter months as apposed to summer. There have been multiple cross-sectional studies that showed an association between lower levels of vitamin D and susceptibility to infection (1). Another recent, well-designed, double-blind placebo study showed that vitamin D administration resulted in a 42% decrease in the incidence of influenza infection (2). Therefore because jetting off to an exotic beach somewhere in the middle of winter to get a healthy dose of vitamin D is not always an option, ensuring you eat a variety of Vitamin D rich foods can be important (although I definitely like the exotic beach idea more). Oily fish is a good source of vitamin D as are egg yolks. Supplementing with a high quality fish oil can be an easy way to boost vitamin D amongst other things!
Another interesting find is recent research done on Zinc. Randomised, double blind placebo controlled trials looked at the efficiency of using zinc to treat or prevent the common cold. The findings from these studies were that a high dose of zinc administered within 24 hours of onset of symptoms reduces the duration of common cold symptoms in otherwise healthy people (3). It is worth noting however that consuming a high dose of zinc on an empty stomach will likely cause an onset of nausea, so ensure you have it with food (4). The biological mechanisms of the effects of zinc are not clear but the current research is suggesting it to be effective against cold symptoms so stock up on zinc next time you feel a cold coming on!
It is important to understand that your overall health status has an effect on your immunity and ability to fight infection so ensuring that you are at optimal health is also important. This means limiting your intake of potentially health harming products like alcohol and processed foods and bumping up your intake of natural, whole and unprocessed foods. I know, sounds like a broken record, but eating good nutritious food really is such an important factor when it comes to improving your health. So improve your immunity with good nutrition this winter, but also have zinc at hand if/when you get struck down!
1. Aranow, C. (2011). Vitamin D and the Immune System. Journal of investigative medicine : the official publication of the American Federation for Clinical Research, 59(6), 881-886. doi: 10.231/JIM.0b013e31821b8755
2. Urashima, M., Segawa, T., Okazaki, M., Kurihara, M., Wada, Y., & Ida, H. (2010). Randomized trial of vitamin D supplementation to prevent seasonal influenza A in schoolchildren. Am J Clin Nutr, 91(5), 1255-1260. doi: 10.3945/ajcn.2009.29094
3. Singh, M., & Das, R. R. (2013). Zinc for the common cold. Cochrane Database Syst Rev, 6, CD001364. doi: 10.1002/14651858.CD001364.pub4
4. Farr, B. M., Conner, E. M., Betts, R. F., Oleske, J., Minnefor, A., & Gwaltney, J. M., Jr. (1987). Two randomized controlled trials of zinc gluconate lozenge therapy of experimentally induced rhinovirus colds. Antimicrob Agents Chemother, 31(8), 1183-1187.