The Guide to Immune-Supporting
Foods, Vitamins, and Minerals

Vitamin A

What it is and why it’s important: Vitamin A exists in a few forms—retinol, retinal, and retinoic acid. It’s critical for maintaining the body’s mucus membranes and regulating the function of macrophages and neutrophils—cells involved in the body’s first response to a pathogen. (You may also know vitamin A for its good-for-your-eyes reputation.)

How to get more of it: If you’re seeking vitamin A, look for beta-carotene. The easiest way to spot foods rich in beta-carotene is by color: If a fruit or vegetable is yellow or red, chances are you’ve found a good source. (Sweet potatoes, carrots, bell peppers, pumpkin, mango, papaya, apricots, cantaloupe…) Green leafy vegetables are typically solid here, too. Vitamin A is fat-soluble, and it’s unlikely to be damaged much by heat when you’re cooking.

Vitamin C

What it is and why it’s important: Vitamin C is an antioxidant that supports a wide range of immune defenses, from promoting the health of your skin (which acts as a physical barrier to germs) to supporting the healthy production and function of white blood cells. Getting enough vitamin C also helps your body absorb iron.

How to get more of it: Vitamin C is readily available in many foods, especially raw fruit and veggies—citrus, strawberries, spinach, kale, bell peppers, Brussels sprouts, and papaya are all great options. What’s important to know is that vitamin C can be degraded by heat and light. You can help protect what’s already in your food by eating your produce fresh and cooking it lightly if at all.

Vitamin D

What it is and why it’s important: Vitamin D is a hormone our bodies produce in response to sunlight, and it’s critical for healthy immune function. Some studies estimate that about two in five Americans are vitamin D deficient. Many studies link vitamin D deficiency with a higher risk of respiratory tract infections, and some draw a relationship between low vitamin D and certain autoimmune conditions. There are a few reasons why your body might not be making adequate vitamin D, like if you don’t spend much time in the sun, wear sunscreen religiously, or have dark skin.

How to get more of it: While it’s usually true that you can get the vitamins and minerals your body needs from a varied diet, it’s difficult—and, we have to admit, unrealistic—to get enough vitamin D from food alone. We recommend a supplement, like the capsule from Hum Nutrition or the oral spray from The Nue Co, to meet your daily goals. That said, if you want to work more vitamin D into the food you eat, there are a couple approaches to try. First up, you can eat more fatty fish, like salmon, mackerel, tuna, or swordfish. Baking your fish may retain vitamin D content better than frying does. (While you’re at it, leave the skin on to get the most out of their omega-3 fats).

Then, mushrooms: Mushrooms, like us, have the capacity to produce vitamin D in response to sunlight, but they’re typically grown in the dark and don’t get much exposure on their way from harvest to your kitchen. If you leave your mushrooms out in the midday sun for a while—we’re talking anywhere from fifteen minutes to a couple of hours—they can produce vitamin D. (How much exactly will vary depending on the type of mushroom, how long you leave it out, and what the weather’s like.) Egg yolks and fortified foods like cow’s milk or orange juice can be other sources.

Selenium

What it is and why it’s important: Selenium is a trace mineral, meaning you only need to consume a small amount. And it’s necessary to dispose of waste products in the body. Here’s how our senior director of science and research, Gerda Endemann, explains it: The killing of infected cells by white blood cells requires reactive oxygen species (ROS) that need to be mopped up. It’s like using bleach to clean—you need to keep it sequestered to where it’s needed and then clean it up so that it doesn’t harm you. Proteins containing the trace mineral selenium help deal with reactive oxygen species during inflammation.

How to get more of it: Meat and seafood tend to be rich sources of selenium, but the most selenium-rich food we know of is the Brazil nut. Just one Brazil nut fulfills twice your daily selenium needs, meaning you could munch on one a day and get more than enough of this vital mineral. Our G.Tox Detoxifying Superpowder includes a day’s worth of selenium, too.

Zinc

What it is and why it’s important: Like selenium (and copper, which we’ll get to next), zinc is a trace mineral, and it plays important roles in many parts of the body. In the immune system, zinc helps maintain healthy skin and mucus membranes (the linings of your respiratory and digestive tracts), which work to keep pathogens out of your body, and supports lymphocyte development, innate immune cell functioning, and the production of some antibodies. It’s also essential for the pathways through which the production of cytokines—signaling cells involved in the immune system—is controlled.

How to get more of it: If you eat meat and seafood, which tend to be rich in zinc, you’re probably good to go here. Vegetarians and vegans might consider doubling down on whole grains, legumes (including soy, tofu, and tempeh), nuts, and seeds. Some of these plant-based sources of zinc also contain a compound called phytate, which inhibits zinc absorption in the body. In order to minimize the effects of phytate, concentrate on sprouted grains and legumes, soaked beans, and leavened breads over nonleavened ones. But don’t be too concerned: Studies show vegetarians and nonvegetarians generally have similar zinc levels—even though vegetarians tend to consume less zinc overall.

Copper

What it is and why it’s important: Copper, like the minerals above, is involved with the cleanup of harmful reactive oxygen species. (Along with zinc, it’s part of the enzyme superoxide dismutase, which inactivates ROS.) And because researchers have linked poor copper status to impaired immune function, there’s ongoing research looking at what exactly copper does to maintain a healthy immune system.

How to get more of it: Copper can be found in a wide variety of animal and plant foods, so the MO here is a varied diet. But if you want to get specific: Oysters, shiitake mushrooms, nuts, seeds, beans, potato skins, quinoa, buckwheat, spirulina, leafy greens, and organ meats, like liver, are particularly good sources. Perhaps our favorite place we find copper is dark chocolate.

Garlic

What it is: Garlic has been used in folk medicine as a catchall treatment for centuries (and likely millennia). It’s been widely promoted by American doctors for heart and vascular health since the 1950s; in the past couple of decades, scientists have been investigating garlic and its compounds for immune health. Garlic contains vitamins and minerals—phosphorus, selenium, manganese, and vitamins C and B6—but research attributes many of its benefits to its antioxidant and sulfur-containing compounds, including alliin and allicin.

How to use it: Heat can interfere with the benefits of garlic by preventing allicin from forming. You can get around this by crushing, pressing, or chopping your garlic and letting it sit for ten minutes—giving allicin enough time to build up—before tossing it into whatever you’re cooking. Or go for a recipe that calls for raw garlic, like salad dressings or toum, which can be used as a dip or spread and is well worth the work it takes to make.

Apple Cider Vinegar

What it is: Apple cider vinegar—colloquially, ACV—has long been part of folk medicine, and it really took off in the late 1950s when a doctor in Vermont published a book claiming ACV had broad benefits. While many of these claims were quickly dismissed, scientists have begun to revisit a few that might hold some weight, including questions about ACV supporting immune function. (Right now, we’re seeing a lot of animal studies—mostly in fish: white shrimp, common carp, sturgeon, zebrafish…) Studies attribute the benefits of ACV to two products of its fermentation: natural probiotics in unpasteurized vinegar, which appear in the bacterial culture called the mother, and acetic acid, which gives ACV its sharp flavor.

How to use it: If you’re considering drinking ACV, you might have heard of people slurping it down as a shot. It’s better, though, to water it down—it’s gentler on your esophagus and digestive tract that way—and to sip it through a straw to help protect your teeth. If you’d prefer a supplement, skip the gummies: A capsule is able to pack in more acetic acid and avoid the added sugar. But remember that pills aren’t equivalent to raw vinegar, especially as far as live probiotics are concerned. The natural foods company Bragg formulated one with 750 milligrams of acetic acid plus vitamin D and zinc for immune support. ACV is also delicious to cook with—it’s a good pairing with flavors like mustard, pork, walnuts, rosemary, and ginger—or stir into a cocktail.

Elderberry

What it is: A long-standing flu season favorite of herbalists, elderberry is native to North America, where it’s been traditionally used in thick syrups and foods for antioxidant support. Studies on elderberry’s antioxidant composition point to phenolic acids, anthocyanins, and the flavonols quercetin, kaempferol, and isorhamnetin. Elderberry contains vitamin C, too.

How to use it: We included elderberry in our Perfect Attendance chews, which are formulated with EpiCor fermented yeast to support healthy immune function. Hilma makes elderberry gummies with added zinc and vitamin C. We’ve also had good experiences with elderberry syrups from local health food stores, which you can take by the spoonful or stir into tea or a mocktail. (If you can find whole elderberries, you can also make a syrup from scratch.)

Manuka honey

What it is: Manuka honey comes from the nectar of flowering manuka trees indigenous to New Zealand. The honey is coveted—and famously pricey—because of its rarity: Bees produce it only during the two to six weeks a year that manuka trees flower. Compounds in manuka honey, in particular methylglyoxal (MGO), have been shown in cell studies to possess antimicrobial and antibacterial activity.

How to use it: When you’re shopping for manuka honey, you want to make sure it contains the compounds you’d expect it to. That’s where the Unique Manuka Factor (UMF) comes into play: It’s an independent certification process that ensures the presence of those key compounds: leptosperin, dihydroxyacetone (DHA), and MGO. (DHA converts to MGO.) UMF ratings—5+, 10+, 15+, 20+, etc.—are assigned based on the levels of MGO and leptosperin detected in each batch of honey. We’re partial to the manuka honey from Comvita, which is certified by the UMF Honey Association to ensure its origins (from the nectar of New Zealand manuka trees) as well as the presence of natural bioactive compounds (like MGO, which is known for its antibacterial activity).

Ginger

What it is: Ginger is best known in Ayurvedic medicine for supporting a healthy inflammatory response in the body. It’s a popular home remedy for an upset stomach, too.

How to use it: There are a zillion ways to cook with ginger. Mix it with miso, sake, and oil to make a marvelous glaze; stick it in a soup; juice it; or work it into spicy, citrusy cocktails. You can also steep fresh-cut ginger in boiling water to make tea (or simply grab a box of ginger tea from the store). We recommend tasting it as it steeps to get the flavor right where you want it; if you let it sit too long, a squeeze of lemon or a bit of honey cuts through the sharp flavor nicely. Or sneak some ginger into your morning smoothie under the sweetness of berries and mandarin orange.

Turmeric

What it is: Turmeric is one of the most well-researched botanicals in the world and is most often associated with a healthy inflammatory response—a benefit that can be attributed to its active component, curcumin. It’s traditionally used in Ayurvedic medicine to promote overall balance, well-being, and a healthy immune system.

How to use it: The most important thing to remember about using turmeric to support well-being is that the curcumin isn’t absorbed well by the body on its own. It’s better absorbed when dissolved in fats (like milk or coconut oil) or in the company of black pepper. If you’re cooking with turmeric, be sure to add black pepper to the mix. If you’re supplementing, check the label for black pepper or black pepper extract. One of our favorite ways to get our turmeric fix is a latte inspired by Indian haldi doodh (golden milk). GOLDE’s powdered turmeric latte froths beautifully into a cup of steamed oat milk.