|Gargling and vitamin D (10,000 IU/week) keep you infection free.|
To test their hypothesis that the combination of gargling in D-supplementation would ward off the common and not so common cold(s), the scientists randomized 600 students into 4 treatment arms:
- vitamin D and no gargling, and
- placebo and no gargling.
- vitamin D3 and gargling,
- placebo and gargling,
an electronic symptom diary, which was intended to test for possible effects of vitamin D on the severity and length of the upper respiratory tract infections (URTIs). The primary and secondary outcomes were the occurrence of symptomatic clinical URTI and laboratory confirmed URTI respectively.
|Figure 1: Effect of gargling and vitamin D supplementation on URTI occurance (laboratory confirmed), viral load, symptom duration and symptom severity (Goodall. 2014)|
And what about the gargling? It's surprising but even plain tap water helps reduce the incidence of upper-respiratory tract infections (-18%)... non-signifcantly, but it helps ;-) If you want to achieve significance and up the effectiveness from -18% to -46%, you would just have to do HIIT gargling, i.e. gargle the water for about 15 seconds three times consecutively, and do this at least three times a day - at least for the subjects in a 2005 study from the Kyoto University School of Public Health that worked like a charm (Satomura. 2005). And if you aim to minimize it by reducing your risk by ~90%, you can simply add some tea catechins (200 µg/mL catechins, 60% of catechins comprise epigallocatechin gallate) to your gargling water (Yamada. 2006).If we look at the effects of vitamin D in isolation, we will see that seventy of those 150 participants had been randomized to the the vitamin D3 groups. The other 80 subjects, were in one of the "no-suppplementation" groups. Based on this data the scientists calculated a "significantly lower risk for laboratory confirmed URTI (RR: 0.54, CI95 :0.34-0.84, p = 0.007)" and "a significantly lower mean viral load measured as log10 viral copies / mL" for the vitamin D3 supplemented study participants.
Interestingly, these results stand in contrast to previous studies, where a different dosing scheme, i.e. 100,000IU/month of vitmamin D3 supplements, did not yield a significant reduction in URTI incidence among the 322 healthy adults who participated in a 2012 study by Murdoch et al. that was conducted between February 2010 and November 2011 in Christchurch, New Zealand and analyzed both the D-intake and the changes in 25-OHD levels (Murdoch. 2012).
- Goodall, Emma C., et al. "Vitamin D3 and gargling for the prevention of upper respiratory tract infections: a randomized controlled trial." BMC Infectious Diseases 14.1 (2014): 273.
- Jolliffe, David A., Christopher J. Griffiths, and Adrian R. Martineau. "Vitamin D in the prevention of acute respiratory infection: systematic review of clinical studies." The Journal of steroid biochemistry and molecular biology 136 (2013): 321-329.
- Laaksi, Ilkka, et al. "Vitamin D supplementation for the prevention of acute respiratory tract infection: a randomized, double-blinded trial among young Finnish men." Journal of Infectious Diseases 202.5 (2010): 809-814.
- Mao, Song, and Songming Huang. "Vitamin D supplementation and risk of respiratory tract infections: A meta-analysis of randomized controlled trials." Scandinavian journal of infectious diseases 45.9 (2013): 696-702.
- Murdoch, David R., et al. "Effect of Vitamin D3 Supplementation on Upper Respiratory Tract Infections in Healthy AdultsThe VIDARIS Randomized Controlled TrialVitamin D3 and Upper Respiratory Tract Infections." Jama 308.13 (2012): 1333-1339.
- Satomura, Kazunari, et al. "Prevention of upper respiratory tract infections by gargling: a randomized trial." American journal of preventive medicine 29.4 (2005): 302-307.