Why now is the best time to build your immunity

Plus, my top 10 foods and herbs to keep your immune system firing on all cylinders, year-round

I’m sure you’ve heard the warnings about a potential second wave of the COVID-19 pandemic beginning this fall—perhaps in a different form from what we saw last winter and through spring.

Of course, the annual influenza pandemic will also be heading our way during the same timeframe.

And this disease double whammy is a big reason why you need to start building your immune system defenses right now. Because what many people don’t understand is that immune health is important all the time—not just during cold and flu (and coronavirus) season.

In fact, it can take as much as three months to entirely replace worn-down immune cells with new, healthy cells. In other words, if you don’t keep your immune system healthy year-round, it leaves you vulnerable to disease and infection.

So while it may seem counterintuitive, it’s particularly important to make sure you’re supporting your immune system during these summer months, when it’s not being taxed by seasonal viruses.

Handwashing and social distancing are great, but you can do more

I’m glad most people have finally learned about practicing good hygiene through proper handwashing and social distancing—which is what I’ve been recommending for years to help keep your immune system healthy and to lower your risk of colds and flu… and now coronavirus.

There are also other natural, easy, and effective steps you can take to build and maintain your immunity year-round, and I’ll discuss those steps in detail in a moment.

But first, let’s take a look at how your immune system functions in the first place…and the No. 1 thing you should never do if you want to stay healthy during cold, flu, and coronavirus season.

Understanding the complicated immune system

The immune system is a complex, interconnected network of cells, tissues, and organs that reside throughout the body—not just in “immune” tissues.

In fact, your gut is home to the majority of your immune cells, and those cells need to be replenished on a continual basis. That’s why nourishing both your gastrointestinal (GI) microbiome and your immune system is important 24/7, year-round.

But while people like to talk about “boosting” the immune system, the key is really more about moderating and maintaining a healthy immune balance.

That’s because chronic inflammation from overstimulation of the immune system contributes to chronic diseases just as much as a poorly functioning immune system does.

In other words, as with most things in life, your immune system functions best when it’s balanced.

How not to fight disease and infection

At the beginning of the coronavirus pandemic, it seemed like all we heard from the talking-head mainstream experts were statements about old drugs, new drugs, and new vaccines to protect us from infections—pandemic or otherwise. (And we’re still hearing about all this now.)

The tragedy is, we didn’t hear much at all about the prescription drugs that actually make us more susceptible to respiratory infections. This includes the drugs I always recommend against—particularly lisinopril and other ACE blockers for high blood pressure, statins for cholesterol, and Tylenol® (acetaminophen).

Some doctors and researchers did attempt to warn the public about these drugs (as I did in my Daily Dispatch throughout the spring). But, immediately, big pharma got its paid mouthpieces to lay down a fog of confusion and controversy about ultimately not stopping these dangerous drugs, even in the midst of a pandemic.

Not to mention, there was very little from the public health “experts” about all of the research showing how micronutrients offer protection against infections and support to the immune system. There was some talk about vitamins C and D (see the sidebar on page 4) and zinc—but only when taken with antibiotics and other drugs.

Sadly, none of these “experts” even gave a cursory glance at the botanicals and foods shown by science to support immune health. (Maybe that helps explain the greater susceptibility of older people to infections like coronavirus, because poor diets and nutrient deficiencies are all too common among this at-risk population.)

Which leads me to my first recommendation for keeping your immune system healthy, naturally…

You (and your immune system) are what you eat

The foundation of the immune system (and every cell, tissue, organ, and system in the body) is diet and nutrition.

And that, of course, starts with food. Or, most notably, a healthy, balanced diet full of fresh, whole foods.

Fake foods (including plant-based, artificial “meats”), fad diets, and dietary restrictions that eliminate entire categories of whole foods do not support your immune system or health.

Nor do the “wrong” foods. In fact, refined sugars and carbs, processed foods, and artificial ingredients have been shown in study after study to weaken the immune system.

That said, there are some particular foods that research shows are especially beneficial for your immune system—both in terms of nutrients and supporting a healthy, balanced GI microbiome. Let’s take a look…

Six healthy foods for top-notch immunity

1.) Asparagus is a delicious stalk that sprouts from the ground each spring. I learned this in the late 1950s, when my family moved into a new housing development outside of Philadelphia that had been built on agricultural fields for the nearby Campbell Soup Company and a New Jersey state prison farm.

Between the blades of grass for the new artificial lawns, stalks of asparagus would spring up, and I would collect them for my mother and our neighbors. I didn’t know at the time that I was helping to provide immune support for our whole block.

Asparagus is a great source of vitamins A, B, C, E, and K. It’s also rich in calcium and iron (which should always come from your diet alone, not supplements).

And because asparagus is loaded with dietary fiber, it’s considered a prebiotic food that supports the natural probiotics in your GI tract. (Probiotics should also only come from foods, not dietary supplements.)

2.) Broccoli has as much immunity-boosting vitamin C in one cup as a glass of orange juice. Plus, UCLA researchers found that a chemical in broccoli and other cruciferous vegetables (including cauliflower and cabbage) can help restore our immune system as we age.1

This chemical, called sulforaphane, switches on genes and enzymes in specific immune cells that combat disease-causing molecules known as free radicals.

3.) Brussels sprouts are another cruciferous vegetable. They look like little cabbages, as indicated by their name in French, choux de Bruxelles.

Brussels sprouts are loaded with vitamins A, B, C, and K; iron and manganese; and fiber. They support the GI tract and digestion, making them critical for immune support.

4.) Mushrooms are one of the few “plant-based” sources of vitamin D (although technically, mushrooms are not plants, but fungi). They’re also good sources of vitamin C, potassium, and fiber.

Numerous studies show the immune benefits of mushrooms, as well as their ability to prevent and reverse many chronic health conditions.

One study of 52 healthy men and women found that eating 5 to 10 grams of shiitake mushrooms daily (which works out to less than one mushroom a day) for four weeks improved immune cell function and gut immunity—and reduced inflammation (a major hidden cause of disease and aging).2

5.) Peppers are a great source of vitamin C. In fact, one sweet (or bell) pepper provides nearly twice the recommended daily allowance (RDA) of C. Hot peppers are high in vitamin C too, but because they’re smaller, you need to eat a handful.

Peppers start out green in color. As they ripen and develop their yellow, orange, and red colors, their content of vitamin A (beta carotene), carotenoids, and antioxidants increases, which show anti-inflammatory and anti-microbial effects. Antioxidants are also key for fighting the free radicals that can attack your immune system.

6.) Sweet potatoes are one of the best sources of carotenoids, which are transformed to vitamin A in the body. And low blood levels of this vitamin have been linked to reduced immunity.  Sweet potatoes are also rich in two types of fiber that support your gut.

Four herbal remedies for immune health

Along with eating a balanced, nutrient-dense diet, you can also consume or supplement with the following herbs—all of which have been found in numerous studies to help support the immune system.

1.) Astragalus. Some studies show that this foundational herb in Chinese medicine (called Huang Qi) may support your body’s production of white blood cells, which the immune system uses to fight infection and viruses.

There’s also interesting evidence that astragalus may support cells in the GI microbiome, which helps promote immunity in the respiratory tract—which, of course, is crucial during cold and flu (and coronavirus) season.3

Recommended amount: In Chinese medicine, astragalus is taken in food quantities, in consultation with a practicioner.

2.) Echinacea. There’s plenty of evidence showing this herb is effective for short-term immune system support. It increases the activity of white blood cells, which shortens the duration and reduces the severity of upper-respiratory infections.

Echinacea shouldn’t be taken regularly. Rather, start only at the first sign of an infection—preferably within 24 hours after your first symptoms appear.

Recommended amount: 450 mg as a supplement, but I prefer brewing an infusion of echinacea, elderberry, and ginger, with honey and lemon, to taste. If you want to make it more of an “immune support broth,” you can add turmeric and garlic.

3.) Elderberry. In the early days of the coronavirus pandemic, there was an attempt to discredit this well-established traditional herbal remedy for immunity. Indeed, there was a flurry of fake news that elderberry could make the immune system “overreact” to the virus and potentially damage the lungs. Fortunately, that was quickly debunked.

Botanical experts cited a variety of studies, including one published last year that found that elderberry extract actually blocks influenza viruses from attacking healthy cells or getting inside them.4 (Viruses need to enter and take over the metabolic equipment of your cells in order to multiply. So, your flu symptoms are actually a result of your immune system fighting off the virus).

And, interestingly, a recent lab study shows that elderberry may have the same mechanism of action against COVID-like viruses.5

Prior studies also suggest that elderberry is even more effective for immune system support when combined with zinc and vitamins A, C, and D.

Recommended amount: Elderberry can be taken as a supplement or syrup, but I don’t think there is sufficient evidence to recommended doses. Some extracts specify adding one or two teaspoons to a drink. I prefer to enjoy it as an infusion with turmeric, ginger, honey, and lemon. Just brew a concoction that tastes good and drink it periodically.

4.) Garlic. This herb is used as a food and as traditional medicine. In terms of the immune system, research shows garlic supports the health and production of white blood cells. Garlic also reduces the duration and severity of infections, and helps protect against infections in the first place.

Garlic is packed with powerful sulfur-containing compounds, which account for its potency and smell. Remember, some of the first antibiotics, before penicillin became widespread, were “sulfa” drugs that used sulfur-containing compounds to fight infections. Garlic is like an ancient sulfa-drug remedy.

Recommended amount: The best way to consume garlic is as a food. It adds zest to virtually any savory dish. So be sure to incorporate it into your homemade, healthy meals as much as possible. (I’m skeptical of the over-hyped, branded garlic powder extracts, which are short on research and long on marketing.)

So, as cold, flu, and potentially coronavirus season approaches in a couple months, you can protect yourself—starting today.

Just follow a balanced, healthy diet. As always, you can’t go wrong with a traditional Mediterranean-style diet, which is full of fresh fruits and vegetables, seeds and nuts, beans, grass-fed and -finished meat, wild-caught fish and seafood, full-fat, organic dairy (like butter, eggs, cheese, and yogurt), olives/olive oil, and alcohol in moderation.

And make sure to include my immune-balancing foods and herbs in your daily, year-round eating plan.

Two vitamins that may support your health in the time of coronavirus

Over the last few months, we’ve been barraged with questionable opinions and some conflicting evidence that various drugs could help treat coronavirus.

Meanwhile, there’s actual scientific research showing that vitamins C and D may lessen the severity of COVID-19 and help people with the virus recover quicker.

Vitamin C. People with severe COVID-19 often have respiratory failure and need to be put on a ventilator. But vitamin C may help. A meta-analysis of eight clinical trials involving 685 people found that taking vitamin C reduced the time spent on a ventilator by an average of 14 percent.

I recommend supplementing with 250 mg of vitamin C, twice a day.

Vitamin D. Researchers from the U.K. evaluated vitamin D blood levels in people from 20 European countries, and found that the populations with the lowest average levels of D also had the highest numbers of coronavirus cases and deaths.

In fact, the researchers noted, “Vitamin D levels are severely low in the aging population, especially in Spain, Italy, and Switzerland. This is also the most vulnerable group [of the population] for COVID-19.”

Meanwhile, researchers at Northwestern University discovered that the link between vitamin D status and COVID-19 may have to do with C-reactive protein (CRP).8 They found a possible association between low vitamin D levels, high CRP levels, and severe cases of COVID-19 in older people.

I’ve written before about research showing that vitamin D reduces CRP. Which is just one reason why vitamin D is always at the forefront of my supplement recommendations.

I recommend supplementing with 10,000 IU of vitamin D a day.


1“Nrf2 Activation by Sulforaphane Restores the Age-Related Decrease of T(H)1 Immunity: Role of Dendritic Cells.” J Allergy Clin Immunol. 2008 May;121(5):1255-1261.e7.

2“Consuming Lentinula edodes (Shiitake) Mushrooms Daily Improves Human Immunity: A Randomized Dietary Intervention in Healthy Young Adults.” J Am Coll Nutr. 2015;34(6):478‐487.

3“The interaction between the gut Microbiota and herbal medicines.” Biomedicine & Pharmacotherapy. Volume 118, October 2019, 109252.

4“Anti-influenza activity of elderberry (Sambucus nigra).” Journal of Functional Foods. Volume 54, March 2019, Pages 353-360.

5“Antiviral activity of Sambucus Formosana Nakai ethanol extract and related phenolic acid constituents against human coronavirus NL63.” Virus Res. 2019;273:197767.

 6“Vitamin C may reduce the duration of mechanical ventilation in critically ill patients: a meta-regression analysis.” J Intensive Care. 2020;8,15.

7“The role of vitamin D in the prevention of coronavirus disease 2019 infection and mortality.” Aging Clin Exp Res (2020).