It’s that time of year again!  Cold and flu season lasts from October to May, although we all know you can get sick with influenza or another flu-like illness pretty much anytime.  Upper respiratory infections are well-named: they lead to symptoms in the upper respiratory tract, the throat, nose, and sinuses. Most of the bugs that cause these upper respiratory infections (URIs) are viruses.  

Why are these types of viral illnesses more common in the winter? One, people are more likely to be in close spaces indoors together when it is too cold (or rainy) to spend much time outdoors.  This proximity with many people and many germs increases the chances of contracting an illness that is spread through coughing or sneezing such as the cold or influenza. Second, many viruses are more resilient in cold weather: their external shell comprises fat molecules which are heartier in cold temperatures. Another factor is that it is harder to get vitamin D from the sun in the winter due both to its being weaker and that we humans tend to be heavily bundled in the winter – making it impossible for our skin to convert the sun’s rays into that wonderful hormone vitamin D.

How can you support yourself during this year’s cold and flu season?  Start with prevention: minimize time spent in crowded indoor spaces, avoid touching your face when in such places, and wash your hands with soap and warm water immediately upon returning home. Wash your hands every time you are going to eat or drink something, or touch your face, including brushing your teeth or taking out your contacts.  Consider supplemental vitamin D during the winter months, or all year-long as directed by your healthcare provider. Vitamin D supports many aspects of your immune system: increasing defensins to destroy virus particles on your skin or mouth, activating macrophages to engulf then extinguish invading virus cells, and modulating T cells.1  If you don’t like swallowing pills, a liquid version can be added directly to food.  Vitamin D is fat-soluble and best absorbed when taken with a fat-containing meal. 

Other tools to add to your winter tool kit?  Vitamin C is an accessible and inexpensive vitamin that can help to support your innate immune system.  Vitamin C can increase natural killer cells, immune system cells that destroy pathogenic bugs like viruses.  The evidence for vitamin C and cold and influenza has been mixed, but one study showed that “megadosing” the vitamin helped with both relief and prevention of upper respiratory infection symptoms.2 Intravenous vitamin C is sometimes recommended because the IV route bypasses the gut, meaning your body can use a much higher percentage of the vitamins than if the supplements were only taken orally.

Echinacea is another natural agent that has long been suggested for winter illnesses.  Echinacea acts as an immunomodulator, meaning that it can both ramp up the immune system (good for the beginning of an infection) and help with resolution at the end of an infection. A meta-analysis showed echinacea can lower the risk of recurrence of URIs and complications such as pneumonia and ear infections.3 

Daily green tea has been shown to decrease the incidence of influenza in the elderly and in children.4,5 Green tea contains a powerful catechin called EGCG, an antioxidant that has been shown to have antiviral activity. 

There are many other herbs and nutrients that we might recommend to support your immune system during peak times of respiratory viral infections.  Please make an appointment to discuss your individual needs or questions.  

As with all supplement recommendations, talk with a doctor who is trained in the nuances of appropriate dosing, interactions with medications and other supplements, and length of therapy. All the doctors at A Woman’s Time have had years of training in botanical and nutraceutical medicine and therapeutic use of high-quality supplements. We also have IV nutritional therapy available; please contact Caitlan Readhead, ND at our office for additional information on IV therapy. 


If you would like to discuss supporting yourself this winter, please call A Woman’s Time at 503-222-2322 to schedule with Rachel Surprenant, ND or another one of our providers.  


  1. Beard JA, Bearden A, Striker R. Vitamin D and the anti-viral state. J Clin Virol. 2011;50(3):194-200. doi:10.1016/j.jcv.2010.12.006
  2. Gorton HC, Jarvis K. The effectiveness of vitamin C in preventing and relieving the symptoms of virus-induced respiratory infections. J Manipulative Physiol Ther. 1999;22(8):530-533. doi:10.1016/s0161-4754(99)70005-9
  3. Schapowal A, Klein P, Johnston SL. Echinacea reduces the risk of recurrent respiratory tract infections and complications: a meta-analysis of randomized controlled trials. Adv Ther. 2015;32(3):187-200. doi:10.1007/s12325-015-0194-4
  4. Yamada H, Takuma N, Daimon T, Hara Y. Gargling with tea catechin extracts for the prevention of influenza infection in elderly nursing home residents: a prospective clinical study. J Altern Complement Med N Y N. 2006;12(7):669-672. doi:10.1089/acm.2006.12.669
  5. Park M, Yamada H, Matsushita K, et al. Green tea consumption is inversely associated with the incidence of influenza infection among schoolchildren in a tea plantation area of Japan. J Nutr. 2011;141(10):1862-1870. doi:10.3945/jn.110.137547