Key takeaways:
~Everyone is exposed to viruses that cause respiratory illnesses, but not everyone develops symptoms.
~ There are research-backed methods for both preventing colds and respiratory illnesses and reducing symptoms if you do get sick.
~ Genetics impacts whether you are likely to get sick from certain viruses.
Staying Well During Virus Season
No one enjoys getting sick—time off work, feeling terrible, and being confined to the couch with a box of tissues — it stinks!
I remember when my kids were little and they got sick. A trip to the doctor inevitably resulted in the “It’s just a virus” comment from the doctor. Nothing to be done, viruses can’t be treated or prevented, and your child will feel better in a few days.
That mindset that there is nothing to do about viruses continued, for me at least, until recently. My thoughts were that everyone catches a cold or gets “the crud” every year or two, usually in December or January.
I was wrong, though. It turns out that there is quite a bit that can be done to help your immune system out and not succumb to being sick for a week.
Viruses are all around us, and we aren’t going to avoid exposure. But getting sick – having symptoms for days or weeks – seems to be something that can be diminished greatly.
Context: Viruses are everywhere, including your nose.
A study in 2015 looked at how many respiratory viruses were found in families in Utah.
For a full year, researchers swabbed noses and asked about symptoms weekly in 26 households (108 people). The results showed that there were 783 viral episodes detected, with less than half of the viral episodes resulting in any symptoms. Viruses were detected in a quarter of the weekly samples, and almost everyone had a rhinovirus detection at some point over the year.
The most common viruses that caused symptoms were coronaviruses, human metapneumovirus, and influenza A. The bocavirus and rhinovirus detections were usually asymptomatic. Households with lots of young kids had more viral infections.
The study concluded that, on average, teens and adults end up with 5 viral respiratory illnesses a year, but that the majority are asymptomatic. Kids 5 and under were much more likely to have respiratory symptoms. (Anyone who has worked with kids and wiped noses all winter knows this.)
Genetics:
Not everyone is equally susceptible to every virus. Some individuals have genetic factors that bolster their defense against certain viral infections. Check out the full article on susceptibility to viral illnesses to see where your superpowers lie.
Prevention and treatment strategies for flu, covid, and colds:
Let me be clear up front: I’m not saying that any of the following are miracle pill cures that prevent all illnesses for everyone. Instead, I want everyone to take away from this article the research-backed ideas for preventing the common respiratory illnesses floating around each year. You may still end up getting sick, but knowing what works and being prepared may help lessen symptoms and duration.
Disclaimer: This is all for informational purposes. If you are sick or have medical questions, please go to your doctor.
Covid and SARS-CoV-2:
No one wants Covid (or long Covid), so let’s talk about some of the safe, inexpensive, and easy things you can do to mitigate your risk.
CoQ10:
In a large population study (4.5 million people), researchers investigated which current medications or supplements were associated with reduced severity and reduced risk of Covid. One of the strongest associations was CoQ10 supplementation, which reduced the risk of hospitalization by 85% in Covid patients.[ref] (Full CoQ10 article)
Gargling:
SARS-CoV-2 is an enveloped virus, and the membrane around the viral DNA is susceptible to being disrupted. For SARS-CoV-2, both Listerine and a povidone-iodine solution can kill it. Gargling with either for 30 seconds can inactivate the virus in the throat.[ref] Other studies showed that chlorhexidine mouthwash was not effective.[ref]
Nasal rinse:
Saline (salt) rinse of the nasal passages is another tried and true way to reduce respiratory infections, including Covid. There are at least 33 studies on reducing viral load and transmission of SARS-CoV-2 using saline rinses in the nose or in gargling.[ref]
Overall, a meta-analysis of 10 trials on povidone-iodine gargling and/or nasal rinsing. When combining the data, the trials show an average reduction in Covid severity of 71% when used early and a 45% decreased risk of getting Covid when used as a prevention.[ref]
Is it safe to use iodine nasal rinse or gargle every day? A study in JAMA on Covid patients who gargled with 1% iodine solution 4 times a day found that some of the iodine was absorbed and caused TSH (thyroid) levels to rise for a couple of days. However, TSH levels went back down as soon as the patients stopped gargling 4 times a day. [ref]
Quercetin:
Several clinical trials early on showed that quercetin was likely effective for reducing the duration of Covid.[ref][ref] A meta-analysis of data from 10 randomized clinical trials shows that quercetin (typical doses 500 mg) reduced symptoms, duration, and hospitalization by around 40-60%.[ref][ref] (More on quercetin)
Melatonin:
Melatonin is produced in high levels at night, but it is more than just a sleep hormone. Melatonin is also important in the way your immune system works, modulating the immune response. Clinical trials on melatonin showed that it reduced symptom progression, days of illness, and death.[ref][ref][ref]
Blocking blue light from screens and LED lights for two hours before bedtime can increase your overnight melatonin production. Alternatively, taking low-dose timed-release melatonin can also increase your levels.
The first study to catch my eye – way back at the very start of the pandemic in March 2020 – predicted which currently available drugs could be useful in fighting off the SARS-CoV-2 virus. Melatonin was one of the drugs that the computer model showed would target what at that time was dubbed “2019 novel coronavirus”.[ref]
Zinc:
Having sufficient zinc is important for your immune system to function well. While zinc is important for fighting off all kinds of infections, it specifically can inhibit replication of the Covid virus. Multiple clinical trials found that zinc, usually in conjunction with other nutriceuticals such as quercetin or resveratrol, was effective in reducing viral load and decreasing days of symptoms.[ref] (More on zinc and genetics)
Vitamin D:
While headlines talk a lot about vitamin D, the research really points to just not being deficient. Adding a lot of vitamin D once you get sick hasn’t been shown to have much effect.[ref] So either get sun exposure or take vitamin D, if you have low levels, before respiratory illness season.
N-acetylcysteine (NAC):
A meta-analysis that pooled data from around 20,000 participants found that NAC supplementation reduced mortality in Covid by 40%.[ref] Other studies show that NAC (600 mg/2x/day) may work to prevent Covid symptoms and infection.[ref]
Colds and respiratory illnesses:
The common cold is a general term applied to symptoms from several different respiratory viruses, including coronaviruses, rhinoviruses, adenoviruses, RSV (respiratory syncytial virus), and bocaviruses.[ref] Many of the Covid coronavirus prevention strategies likely work for common colds as well.
Sleeping enough:
Sleeping less than 6 hours a night increases the risk of developing a cold by 4-fold.[ref] This means that during cold and flu season, prioritizing getting to bed on time is really important.
Melatonin:
Melatonin as a general antioxidant and immune function regulator is likely effective against many viral respiratory illnesses including the viruses that cause the common cold.[ref][ref][ref] Animal studies show that it prevents lung damage in RSV and prevents staph infections.[ref][ref]
Gargling:
There are tons of studies on gargling daily to prevent respiratory illnesses. For example, a study on Japanese children found that gargling with either green tea or just plain water reduced the risk of respiratory illnesses by 30-40%. [ref] A large study showed that just teaching kids about hand washing and gargling reduced influenza infections by 20-30%.[ref]
Vitamin C:
Studies on vitamin C for reducing the risk of the common cold show various results – depending on the study group and the amount of vitamin C taken. One recent study on Korean army personnel found that 6g of vitamin C per day reduced the risk of colds by 80%. [ref] A meta-analysis of studies in kids under the age of 6 found that vitamin C didn’t prevent colds but it reduced the duration of the cold.[ref]
Vitamin D:
A prospective, randomized double-blinded placebo-controlled study (the gold standard here) found that taking vitamin D supplements daily for 16 weeks reduced the duration and severity of respiratory infections in adults aged 45-74.[ref]
Honey:
Multiple randomized controlled trials in children show that honey works better for a cough than placebo, diphenhydramine, or dextromethorphan.[ref][ref][ref]
Influenza: Beating the flu
First, keep in mind that genetics plays a role in whether you are likely to get certain variants of the flu virus. We all have different variants in immune system genes that give us protection from some viruses and susceptibility to others. You can read about flu genes here.
Gargling and Nasal rinse:
Researchers found that iodine throat spray or iodine gargle (both at 0.23% iodine) would kill the avian flu virus within 10 seconds of application.
Gargling and hand washing:
A large study showed that just teaching kids about hand washing and gargling reduced influenza infections by 20-30%.[ref]
Hesperidin:
Hesperidin has been shown in several cell studies to inhibit the replication of influenza A. However, there aren’t any clinical trials of hesperidin for the flu.[ref]
Black elderberry:
The anthocyanin in black elderberry extract has been shown to inhibit neuraminidase in cell testing.[ref][ref]
Zinc: An important co-factor in immune response pathways, zinc deficiency can increase the risk of severity in respiratory viruses, including the flu.[ref]
Quercetin:
A natural flavonoid and popular supplement, quercetin has been shown in several studies to inhibit the replication of influenza.[ref][ref]
Curcumin:
A component of the spice turmeric, curcumin has been shown in multiple studies to have antiviral activity against influenza viruses.[ref][ref]
Vitamin C:
A small study in healthy adults showed that 1,000 mg of vitamin C taken every hour for six hours at the onset of symptoms reduced symptoms by 85%. After the first six hours, participants took 1,000 mg three times a day.[ref]
N-acetylcysteine (NAC):
NAC provides the cysteine precursor that the body needs in order to make glutathione. NAC also acts as a mucolytic, thinning out thick lung mucous. An Italian study found that 600 mg/2x/day for 6 months significantly reduced the number of influenza-like illnesses in older adults. [ref]
Wrapping this up:
Research shows that there are quite a few things you can do to prevent viral respiratory infections or reduce the duration of symptoms.
There are a lot of overlaps in what works for different viral infections. The easily done and yet effective preventative for all of these viruses is gargling. Gargling with iodine or listerine, if you have symptoms or exposure. But just gargling with water or green tea seems to help in preventing all types of respiratory illnesses.
Melatonin helps you to fight off viruses overnight. Prioritizing your sleep schedule, sleeping in the dark, and taking supplemental melatonin if needed are all relatively simple. Think about how many times you’ve gotten sick when traveling across time zones — or after a night out at a party. Just sticking to a solid sleep, wake, and eating schedule helps your circadian rhythm and immune response.
N-acetylcysteine (NAC) has some fairly good studies on it for a variety of respiratory infections, and it may be something to consider as a preventative for people who are older or who regularly catch respiratory infections. Talk with your doctor, of course, if you’re on any medications before starting a supplement.[ref]
The key is to be prepared. The last thing you want to do when you wake up with a cold is to run to the store or even try to think about what you need. Have a go-to supply ready if you start feeling a sore throat. If you don’t normally use mouthwash, get a little bottle of Listerine — or an iodine-based mouthwash. If you’re planning on making your own 0.2 – 1% iodine solution, figure out how to dilute your iodine ahead of time. Don’t try to do the math with a cold.
Have a ‘cold box’ ready for that first tickle of a sore throat. Whether it is quercetin, NAC, melatonin, gargle/nasal rinse, zinc, elderberry, honey, or vitamin C – the key is to have them on hand and actually take them when you first start thinking you’re getting sick. Take care of yourself, get plenty of sleep, and avoid stressors.
About the Author:
Debbie Moon is the founder of Genetic Lifehacks. Fascinated by the connections between genes, diet, and health, her goal is to help you understand how to apply genetics to your diet and lifestyle decisions. Debbie has a BS in engineering from Colorado School of Mines and an MSc in biological sciences from Clemson University. Debbie combines an engineering mindset with a biological systems approach to help you understand how genetic differences impact your optimal health.