These are things that you can do today that don’t cost anything. We recommend you prioritize these basic steps for protecting and improving your health — and potentially your immune system.
While these actions are always important aspects of maintaining good health, they may be crucial during times of increased risk, like now.
- Proper handwashing: the coronavirus is killed by proper handwashing for 20 seconds with soap or using hand sanitizer that is greater than 60% alcohol.
- Don’t smoke: Smokers have an increased risk of catching infections and suffering severe complications from those infections.
We shouldn’t need more reasons not to smoke, but a time like this highlights the importance even more.
- Get adequate sleep: Sleep is important for health in general, and as a bonus it may also benefit our immune function. For instance, one study showed those with insomnia had, on average, less immune response to the influenza vaccine, while another study in twins showed those with worse sleep had altered expression of genes related to immune function.
Last — and we can file this one under “How in the world did they convince people to do this study?” — 153 volunteers were inoculated with the rhinovirus (the virus that can cause the common cold). They found those who slept less than seven hours were three times more likely to develop symptoms than those who slept more than eight hours.
Again, the science in this area may not be robust, but when it comes to overall health, proper sleep helps. In times like these, you should prioritize sleep hygiene.
If you’re isolated at home, that likely means more time on electronics like tablets, phones, and TVs. This may be a good time to invest in blue-light blocking glasses and to look for non-tech related activities to do in the evening, like puzzles, crosswords, or reading an actual book (not an ebook!).
- The right amount of exercise: Observational studies show that those who exercise tend to suffer fewer infections than those who do not.
While those studies have confounding variables, the general consensus is that exercise overall is likely beneficial, with some caveats.
Some studies show bouts of strenuous exertion (>1.5 hours with an average heart rate >75% maximum) may temporarily decrease immune function. In addition, elite athletes who “overtrain” tend to suffer from infections more frequently than others.
Our advice? Stay active, but remember: now is not the time to start a new high intensity exercise routine. If you already enjoy strenuous exercise, consider decreasing the frequency or intensity by 10-20% (this is not scientifically backed but is recommended by some experts). Also, try to focus on home or outside exercise. Shared gym equipment, like weights and cardio machines, may be surfaces that transmit the virus.
- Stress management: While acute stressors may temporarily enhance immune functions, chronic stressors likely diminish immune function.
Worrying about the stock market, stressing about having enough toilet paper, and focusing on the uncertainties of the future can raise cortisol levels, which may negatively impact our immune function. While data is difficult to interpret in this area, one study showed medical students with increasing stress levels before their final exams had decreased function of natural killer cells, the cells that are the “first responders” of our immune system.
We can’t make this stressful situation disappear. But we can all take measures to control our response to stress. Meditation, mindfulness exercises, and getting outside and going for walks are all examples of activities that are free and relatively easy to do.
The website Ten Percent Happier has a free “coronavirus sanity guide” that may help. Whether stress management techniques help your immune system or not, they can potentially help blood pressure, blood sugar, and make your days much more pleasant.
- If you drink alcohol, drink in moderation: In times of stress, some people turn to alcohol as a coping mechanism. While meditation, nature walks, and mindfulness exercises are likely healthier ways of coping, for some they aren’t enough, and alcohol adds a little something extra. There’s no judging here. We all have to do what we can to get through tough times.
However, studies show a relationship between chronic heavy alcohol consumption and increased susceptibility to infections.
Perhaps most pertinent for the discussion about COVID-19, some of these studies showed an increased risk among heavy drinkers of acute respiratory distress syndrome (ARDS), the lung complication responsible for most of the COVID-19 related deaths.
The trick is knowing where to draw the line. While there is little science, most experts suggest that a reasonable daily limit is two drinks for men and one drink for women. Keep in mind that following a low-carb lifestyle may decrease your tolerance to alcohol, so you may need to adjust your intake. You can read more about alcohol and low-carb lifestyles in our evidence-based guide.
Could taking vitamins, minerals, or other supplements help protect you from COVID-19? Contrary to what you might read on the internet, this is a question that can’t be answered definitively. Here’s what we do know about certain supplements that reportedly have immune-boosting properties.
For decades, Vitamin C has been used to help prevent the common cold. Among other functions, this vitamin can help maintain healthy skin that provides a barrier to germs and other harmful invaders. In addition, some — but not all — studies suggest it may improve the function of certain white blood cells that fight infection.
In addition, there is conflicting evidence about the potential mortality benefits of high dose Vitamin C for patients with sepsis, the most severe form of systemic infections.
While it’s unclear whether taking a Vitamin C supplement is beneficial for COVID-19, for most people there’s no harm in taking up to 2,000 mg per day (the upper limit set by the National Academy of Medicine).
For smokers and high-risk individuals, it’s definitely worth considering. Vitamin C is water-soluble, so your body will excrete whatever you don’t need into your urine. However, at very high doses, Vitamin C may cause diarrhea or increase the risk of kidney stones (especially in men), so be sure not to exceed 2,000 mg daily.
As both a hormone and a vitamin, Vitamin D plays a number of important roles in health.
In recent years, people have taken very high doses of Vitamin D with the intention of boosting immunity. But is this an effective tactic? A 2017 systematic review of 25 randomized trials found that taking a Vitamin D supplement seemed to have a mild protective effect against respiratory-tract infections in most people, but provided much greater protection in those who were very deficient in Vitamin D.
If your Vitamin D levels are low, you may have a better chance of staying well if you supplement with 2,000 IU per day (or more, with medical supervision). Many — perhaps even most — people are deficient in vitamin D.
So it’s probably wise to take a Vitamin D supplement right now, especially if you’re at increased risk for COVID-19.
Of course, your body can make Vitamin D on its own when your skin is exposed to sunlight, so try to get some sun whenever you can. How much sun depends on the time of year and your location. A good starting point is 15 minutes of exposure to a large body part (such as the torso or back). Just remember to avoid sunburns, as excess sun exposure carries its own risks.
Zinc is a mineral involved in the white blood cell response to infection. Because of this, people who are deficient in zinc are more susceptible to cold, flu, and other viruses. One meta-analysis of seven trials found that supplementing with zinc reduced the length of the common cold by an average of 33%.
Whether it could have a similar effect on COVID-19 isn’t yet known.
Taking supplementary zinc may be a good strategy for older people and others at increased risk. If you decide to take zinc, make sure to stay below the upper limit of 40 mg per day, and avoid administering nasally, due to the risk of olfactory complications.
Turmeric is a spice commonly used in Indian and Asian cuisine, including curries. It contains a bright-yellow compound known as curcumin, which emerging research suggests might enhance immune function.
However,there isn’t any convincing evidence showing that it helps fight viral infections yet.
On the other hand, adding turmeric to your food adds flavor, and taking a curcumin supplement is unlikely to cause any harm in otherwise healthy people. If you have any medical conditions — especially if you take blood thinners — check with your doctor before supplementing with curcumin.
Echinacea is an herb that can reportedly help prevent the common cold. But is this reputation well-deserved? A recent systematic review of randomized trials found that echinacea may possibly have a mild protective effect against upper-respiratory infections but doesn’t appear to reduce the length or severity of illness.
While it’s impossible to say whether it might offer any protection against COVID-19, it appears to be safe to take on a short-term basis. If you’re at high risk, you may consider taking it for the next several weeks.
Garlic, a popular and pungent herb with a characteristic aroma, is widely believed to have antibacterial and antiviral effects, including helping to fight the common cold.
A 2014 randomized controlled trial did find that people who took a garlic supplement had fewer colds and recovered more quickly from colds than people who didn’t take garlic.
Although this is encouraging, this is just one study. Other high-quality trials are needed to confirm whether garlic is truly beneficial for the common cold or other upper-respiratory infections. For now, enjoy garlic for its zesty flavor and unmistakable aroma rather than counting on it to boost your immunity during the coronavirus pandemic.
Fruits, veggies and seeds
Getting plenty of fruits, vegetables, and seeds is a common recommendation seen on many sites, but the evidence is inconclusive if it truly helps. In one often-quoted study, elderly volunteers were randomized to less than two or greater than five daily servings of fruits and vegetables.
They found the group with the higher fruit consumption had a better immune response to the pneumonia vaccine but not to the tetanus vaccine.
Another claim is that “eating the rainbow” and getting “adequate phytonutrients” improves immune function and reduces infection risk. Unfortunately, “eating the rainbow” and getting “adequate phytonutrients” are poorly defined terms, and such messages are usually compromised by being based on nutritional epidemiology studies heavily impacted by the underlying diet (i.e mostly in high-carb diets) and healthy-user bias.
Therefore, we cannot conclude that any one specific food will improve your immune function. However, as with many other potential health benefits, it makes sense to stick to a diet that provides adequate essential nutrition and is rich in minimally processed natural foods. It may not be more complicated than that.
Refined carbs and sugars
Laboratory evidence suggests sugar may impair white blood cell function, but no credible evidence shows eating it makes you get more infections.
However, other evidence suggests acute rises in blood sugar may increase risk of infections and complications.
Therefore, it would make sense that we want to limit these blood sugar elevations. Refined carbohydrates and simple sugars are two of the biggest offenders for blood sugar spikes and therefore should probably be avoided.
This is different than saying studies show avoiding these foods results in fewer infections. (We don’t have that evidence.) Plus, as we have mentioned many times, it’s difficult to isolate the effect of one food since any food’s effects have to be studied within the context of the underlying diet (i.e. standard American diet vs. a low-carb diet).
However, one simple solution is to use the measurement of your own blood sugar as a guide. If higher blood sugar is associated with more complications, it makes sense we want to limit that.
We suggest measuring your blood sugar either with a regular glucometer or, even better, with a continuous glucometer (CGM) if you have access to one. If the foods you eat cause your blood sugar to rise above 140mg/dl (7.8mmol/L), consider eating something different.
Studies show that a low-carb, moderate protein, higher fat diet effectively reduces blood sugar and can even reverse type 2 diabetes.
We don’t have proof that this will “boost your immune system,” but it may help keep blood sugars in check which may be associated with decreased infectious risk.
Chicken soup/bone broth
Treating colds and the flu with chicken soup may be the most popular urban myth of all time. Surprisingly, it may not be 100% a myth.
One study showed chicken soup “inhibited neutrophil migration,” which the authors suggest could improve our ability to recover from infections.
However, this is one of those instances where laboratory findings may not translate to clinical improvements such as fewer or less serious infections. But it’s hard to argue with a tasty homemade soup with chicken, a few low-carb veggies, and plenty of real salt. Immune booster or not, it sounds like a great meal for a wintery day in self-isolation. We chalk that one up to good self-care.