Part of what makes coronavirus so scary for some people is the feeling of helplessness. There's no vaccine and no cure. We simply have to sit and wait and hope.

Maybe we're not totally helpless though. Just like hand washing can help lower our chances of getting the virus, a healthy diet may aid us in fighting it off. If you contract COVID-19, you're relying on your body's immune system to recognize the enemy and create antibodies to defeat it.

If this were an actual war between humans, and there was an enemy at the gates, wouldn't we want our army to be strong, well-fed, and ready for battle? The same logic can be used when we're thinking about our immune system. We want our white blood cells warriors to be capable of swiftly defeating the enemy.

Just as human warriors who are starving, nearsighted, hard of hearing, or disabled would have a harder time defeating an enemy, our immune system has a harder time defeating viruses when it's handicapped by a lack of nutrients.

You won't hear this advice from most medical professionals. Nutrition is not well-studied by most doctors. Their continued education is often facilitated by pharmaceutical companies, not the kiwi fruit coalition. As a result, "natural" medical interventions are often used as last resorts, instead of our first line of defense.

Let's take a look at what we can do to train our army of immune cells and prepare for battle with coronavirus:

Selenium

Eat a couple Brazil nuts every day.

Coronavirus seems to steal from your body's selenium reserves. In addition, for immune cells to have a high killing capability, they need antioxidants to protect themselves, which are supported partly by selenium [1].

It would be smart to start eating foods high in selenium, including oysters, liver, and sardines. Shrimp, eggs, and salmon are all good sources of selenium as well. If you're vegan or looking for the easiest solution, have a couple Brazil nuts every day and you'll be getting all the selenium your body needs. Don't overdo it on the Brazil nuts though–ten is not better than two in this case.

Vitamin C

Pop a Vitamin C tablet every day, 500–1,000 mg.

Vitamin C is helpful against many viral infections, but vitamin C deficiency is widespread. 31% of Americans have inadequate intakes of vitamin C [2]. Vitamin C is needed to maintain levels of glutathione, the immune system's primary antioxidant and a key component of being able to fight off pathogens.

Vitamin C is one of the safest nutrients. While many nutrients are actually toxic at megadoses, vitamin C has been found to be safe at almost any dose. It's one of the most well-studied supplements, and certainly safe to supplement at doses of a few grams per day. Some doctors have suggested that megadoses of vitamin C are an effective treatment against coronavirus, but the jury is still out on those claims [3].

It is possible to get enough vitamin C from food, but you'll have to eat a lot of citrus fruits, bell peppers, kiwis, broccoli, and kale. To be safe, it's probably best to supplement with 500 mg of vitamin C per day.

Vitamin D, Vitamin A, Water

Get plenty of sunshine, drink enough water, and eat orange foods.

Wherever coronavirus might enter your body–mouth, nose, and eyes–you have compounds that kill pathogenic microbes. Secreting enough of these compounds is dependent on having enough vitamin D, vitamin A, and water.

The best source of vitamin D is the sun. The UV rays in sunlight also happen to kill viruses and give you an attractive tan. Triple win. If you don't get much sun, consider supplementing with vitamin D3.

Eat foods rich in vitamin A, including liver and egg yolks. While the form of vitamin A found in plant foods is not as bioavailable, it is still helpful. Carotenoids like beta-carotene in sweet potatoes, carrots, and squash and lycopene in tomatoes are what give those foods their orange and red colors. Dark leafy greens like kale, spinach, and chard are also good sources of vitamin A precursors.

For water, you don't need to overdo it. Just don't be dehydrated. Listen to your body; if you're thirsty, drink water.

Iron

If you eat red meat, don't supplement iron.

Iron is a tricky one. While your body's immune system needs iron to be most effective against pathogens, too much iron can also feed the pathogens themselves. Iron is an essential mineral for nearly all life, including coronavirus. Not enough iron and your immune system is limited; too much iron and your body can't starve pathogens of this key mineral.

If you're eating a real food diet that includes red meat, you're probably getting enough iron from food. To prevent iron overload, avoid iron supplementation and give blood regularly (for men and post-menopausal women). If you don't eat meat or shellfish, your risk of having excessive iron levels is low.

Vitamin C also enhances iron absorption, so there's more for you and less for unwelcome pathogenic visitors.

Zinc and Copper

Enjoy oysters and dark chocolate.

Just like with vitamin C and iron, it's important to get enough zinc and copper to give your immune cells the best chance of success in battle against coronavirus. Fortunately, the foods highest in zinc and copper are also delicious.

Shellfish and especially oysters are by far the best source of zinc, with a half dozen oysters per week mostly satisfying your zinc requirements. Chocolate is an excellent source of copper, with just a few squares of dark chocolate (85% or above) per day satisfying your copper requirements.

Cashews are also a good source of both zinc and copper.

Iodine

Eat stuff from the sea.

Iodine is an extremely effective mineral employed by our body for immune killing. Like with vitamin C, high dose iodine treatment has been used to cure some infectious conditions.

To keep your immune warriors strong, feed them a few hundred micrograms of iodine daily. You can supplement with iodine, or simply eat foods from the sea. On days you eat seafood, shellfish, or sea vegetables, there is no need to supplement.

My favorite form of iodine "supplementation" is to eat seaweed snacks.

Smoking and Air Pollution

Don't smoke.

Coronavirus started in Wuhan, China, where air pollution is a major problem and a high percentage of the male population smokes. Whereas only 3% of Chinese women have smoked, 62% of Chinese men have been smokers at some point. The coronavirus death rate among men in China is 2.8% compared to 1.7% for women, and some point the finger at smoking rates to explain the difference [4].

Coronavirus seems to work by binding to the ACE2 receptor in the lungs. One study found that cigarette smokers have a higher density of ACE2 receptors. If that relationship is causal, lung health may play a major role in fighting the virus, and air quality would play a role as well [5, 6]. While there's not much you can do if you live in an extremely polluted city, you can certainly refrain from intentionally sucking down smoke in the form of cigarettes.

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Summing it up, in order to boost your immune system in preparation for battle with coronavirus, you may want to get more of the following:

Brazil nuts, bell peppers, kale, kiwis, broccoli, liver, egg yolks, sweet potatoes, carrots, squash, oysters, dark chocolate, cashews, shellfish, seaweed, clean air, water, and sunshine.

Even if/when coronavirus is no longer a threat, we want our immune systems to be strong, healthy, and able to easily fight off infection.

Our immune system is not just sitting around waiting for the next outbreak; with every breath of outdoor air, we take in 50,000 germs [7]. While most of these germs do not cause us to get sick, they do keep our immune system busy, regardless of coronavirus.