Supplements- Cold and Flu

As Nutrition Coaches we often get asked if there are supplements that can “keep me from getting the flu”  or more recently COVID-19. This is the first of at least two posts on nutrition and cold/flu.

Well, the answer is complicated.  First, we are not giving medical advice.  If you think you may have the Flu, a bad cold or anything else get medical attention. Second, there are not a ton of solid studies, but there is pretty good evidence (both cohort studies, and real trials) as well as a plausible mechanism for some things.   Also, most of the supplements help you AVOID getting something, and/or shorten the effects of an infection. (Note: I pull a lot of my info from different sources, I suggest,, PubMed, and the National Institute for Health (NIH)). Third, and probably just as important.  There are a bizillion micronutrients and helpful chemical compounds in the food we eat that impact the way our bodies grow, perform and protect us. The best advice I have ever heard is ‘eat the rainbow’. Eat as many different types of colorful veggies and fruits that you can. Start there. Variety and diversity of nutrients.

That being said let’s talk some supplements with a pretty good history of studies.

The Big Three.

Three vitamins/minerals that we would recommend almost all of the time, even if you weren’t sick (and probably better to take before you are sick).

Vitamin C

OK, so this is a pretty easy one.  Vitamin C makes sense because vitamin C is intimately involved in the function of your immune cells and skin (among a bunch of other things). Unlike most other animals, our (Human) bodies can’t make Vitamin C so you need to consume it. The good news is that studies have shown that if you are actively exercising regularly (CrossFit anyone?) while also regularly taking vitamin C you are half as likely to catch a cold and if you do catch one it will likely be shorter and less severe.  The bad news…if you aren’t exercising intensely, regularly and taking vitamin C before you catch a cold, it isn’t likely to help that much. Vitamin C for preventing and treating the common cold. 

How much 200mg-2000mg (and it almost always comes with Vit E)- depending on how much fruit and dark leafy greens you eat.

Vitamin D

I could go on for a long time about Vitamin D as it is involved in everything from cognition to bone health, cancer prevention, etc.  However the bottom line in this context is that Vitamin D is involved in the regulation of immune cells when they are dealing with infections as well as a whole lot of other functions.  Unlike Vitamin C our bodies can produce Vitamin D from cholesterol when we are exposed to sunlight (specifically UVB). We just don’t get enough sunlight due to a large number of factors (latitude, sunscreen, inside…you get the idea). 

Suggested Vitamin D supplementation, 1,000 -2,000 IUs of D3 (not D2).  You should take this with food that contains fat as D3 is a fat-soluble vitamin. We highly recommend you get your levels of Vitamin D checked regularly by your Doctor.  (For reference 20-50 ng/ml is considered adequate…if you are older 35-40 ng/ml is considered optimal for bone health)  


Sucking on zinc lozenges can limit virus replication and reduce respiratory tract inflammation.  Studies have shown the ability to reduce the duration of a cold by 2-4 days. The important thing is that this is effective because it affects virus replication in the throat and nose.  If you chew the lozenge, it loses its efficacy. Also, please know that the dose to reduce the duration of colds (75-95 mg/day) is above the safe upper limit (NIH). This is not usually a problem for the duration of a cold (2 weeks), however, if you start having additional stomach problems (nausea, cramps, diarrhea, headaches) stop supplementing with zinc.  (Also watch other sources of zinc, it is in many multivitamins and other supplements…for example some of the fizzy Vitamin C drinks like Emergen-C contain zinc).  

The next post will be on some other things that seem to have some pretty good support and you see a lot on the interwebs.  (Elderberries and Umckaloab – African Geranium)



Free Intro

Talk with a coach about your goals, get the plan to achieve them.

fill out the form below to get started!

Take the first step towards getting the results you want!