The 7 Best Foods to Eat to Fight Colds and Flu

Taking care of our immunity is an everyday priority. That means getting our shots and also watching what we eat, getting enough sleep, and managing stress to the point where it doesn't make us sick. Immunity and understanding how to "arm" our immune systems have become a familiar topic, and there are foods you can eat to give your immune cells the weaponry they need to go to battle against colds, flu, and the coronavirus, as well as any other infections.

When the news reports that the infection rate of COVID-19 cases is rising by the day, and with the Omicron variant on the march, having arrived in 21 states, or about 1/3 of America, this is the time to do everything we can to fortify our immune systems against all invaders including the traditional winter worries: Cold and flu cases that are ramping up this time of year. "It's just a cold!" has become a familiar refrain when anyone sounds stuffed up or sneezes. As if "just a cold" is nothing to sniff at. In fact when you're immune system crashes it takes more time to re-assemble and get back on track, so eat these foods to strengthen your immunity and do your best avoid getting sick at all!

Here are 7 foods to eat (and what to drink) to fight off colds, flu, and COVID-19

1. Oranges

Vitamin C has been shown to reduce the duration of a cold, though the evidence is scant that it can prevent you from getting sick in the first place. Still, the review of studies done on over 11,000 people taking C supplements did show that taking C could reduce a cold's duration and severity. But scientists also say that there is a difference as to how C is absorbed when it is eaten in food such as oranges, grapefruit, kiwi fruit, and other citrus fruit such as lemons and limes and it's always better to get your vitamins in their most natural form: in whole foods.

Vitamin C for colds has been studied for 70 years, since the Nobel Prize-winning chemist Linus Pauling first recommended taking it for health, since he discovered by measuring circulating vitamin C, in the blood, it was associated with a lower risk of hypertension, heart disease, and stroke, and he suggested it may also be a cofactor in fighting off infection. Newer research tells us you can take 200 milligrams a day when you first start to feel sick and that will help reduce symptoms and possibly the duration of the virus. It works best in children and those under physical stress, according to the latest studies. So if you work out a lot or are training for a big event, you may want to supplement as a way of helping your body stay strong and healthy.

The RDA for vitamin C is 90 milligrams, and taking more than 200 milligrams a day could lead to kidney stones or an upset stomach, but if you eat an orange a day, you are getting about 50 milligrams. A kiwifruit has 64 milligrams and half a grapefruit has 38 milligrams. Eat your vitamin C for the best immunity fighting potential, since it comes packaged with fiber and other healthy antioxidants and vitamins that can further provide protection for your body when you need it most.

2. Blueberries

The thing about blueberries that makes them so powerful is their color. It turns out that the same pigments that create that shiny blue tone are powerful phytochemicals that, once in your body, act like little hand grenades that your immune's T-killer cells use to blow up viruses.

Blueberries and red grapes both can be equally powerful according to review studies: "In an analysis of 446 compounds for their ability to boost the innate immune system in humans, researchers discovered just two that stood out from the crowd: Resveratrol found in red grapes and a compound called pterostilbene from blueberries," according to Science Daily.

The study was first published in the journal, Molecular Nutrition and Food Research. These compounds, called stilbenoids, worked with vitamin D to raise the body's immune function. So while you're eating your blueberries be sure to get your vitamin D, either by supplementing or by sitting in the sun as you eat your fruit on a bowl of whole-grain cereal and plant-based milk.

3. Tomatoes

Lycopene, which gives tomatoes their red coloring, is good for your body, from fighting off heart disease to strengthening the body's response to cancer. How are these things connected to colds and flu and your immune system's day-to-day workload? When your cells are healthy, and all systems are humming along, your body can conduct the "immediate" work of avenging its turf against invaders and illness. And conversely, when you are clear of infectious agents such as bacterial infection and viruses, the body can do the "long-term" work of staying healthy for decades to come.

In a health update on the health benefits of lycopene, epidemiological studies have associated tomato consumption with a decreased risk of prostate cancer as well as the risk of chronic diseases such as cardiovascular disease. Lycopene supplements have been reported to affect diseases ranging from cancer to heart disease to asthma. A vitamin A, lycopene is a "helper" compound that appears to allow the body to activate other antioxidant molecules, such as vitamin E.

Studies have shown that lycopene, which is easily absorbed from tomato juice, sauce, and tomatoes in your salads, may help the body fight off cancers ranging from breast to prostate and possibly lung cancer. So while you're trying to stay healthy in the short term, they also help you stay healthy in the long term.

4. Broccoli and other cruciferous vegetables

Do you know that smell that comes from broccoli when you start to steam it? That is sulforaphane, a gassy chemical in the vegetable, that when it hits the body acts as an antioxidant to switch on your specific immune cells, telling them to go out and fight free radicals that can make you sick or cause long-term harm like promoting cancer growth.

When sulforaphane is in the wild it's the plant's response to a bug nibbling at it, or other "damage" that comes from being broken. As you chew your broccoli – or Brussels sprouts or cauliflower – this same gas tells the body to seek out the "bugs" or invaders and get ready to kill the harmful agents. What works in nature works in our bodies. The best way to prepare broccoli is to slightly heat it but not overcook it since that reduces the amount of sulforaphane that gets delivered into your body with every bite. Also, do use the leaves, and even the stems, since the entire plant contains sulforaphane and can help prevent you from getting sick.

In a study on sulforaphane and the immune system, it appears to boost the activity in the lymphocytes while inhibiting the production of pro-inflammatory TH17 related cytokines. That's good news for anyone with COVID-19 since these can lead to inflammatory over-reaction that can serve to make you sicker by inflaming the lungs.

5. Spinach

Not only is spinach full of vitamin C, but it also delivers a hefty dose of vitamins A, K, iron, folate, and beta carotene, all of which work together to strengthen the infection-fighting ability of your immune system. Spinach is also full of fiber which can help lower your insulin response, keep blood sugar in check and help lower inflammation, which in turn helps the immune system operate at its top ability. In a study, "Coronavirus disease (COVID‐19) and immunity booster green foods: A mini-review," the researchers found that eating plant‐based foods worked for enhancing the immunity of all aged groups against COVID‐19.

"Various vitamins like C, D, and E are investigated to provide important aspects for improving immunity. Fruits like oranges, papaya, kiwi, and guava are rich in vitamin C, while vegetables like eggplant, bell peppers, beetroots, spinach, and cauliflower are known to be quite rich in vitamin C and are good for immunity," the study concluded.

Spinach is one of these multi-taskers that help unlock other vitamins, including vitamin D and vitamin E that are powerful antioxidants that help the body protect against cell damage.  Eating spinach along with these other plant-based foods helps your immune system not only directly but indirectly as a way of making these other nutrients more bioavailable.

6. Garlic

Garlic has long been thought of as a miracle healer. In a review of how garlic helps fortify the immune system, the researchers found the complex biochemistry of garlic makes it possible for variations in processing to be studied. The active ingredient, Allium sativum, has been shown "to enhance the functioning of the immune system by stimulating certain cell types, such as macrophages, lymphocytes, natural killer cells [and others]" the study found. But garlic doesn't just help stomp out colds and flu, the researchers concluded, but also helps the immune system to stay active and revved up to fight off other serious diseases.

"Because immune dysfunction plays an important role in the development and progress of several diseases," the authors wrote,  we critically examined immunoregulation by garlic extracts and compounds isolated, which can contribute to the treatment and prevention of pathologies such as obesity, metabolic syndrome, cardiovascular disorders, gastric ulcer, and even cancer. We concluded that Allium sativum modulates cytokine secretion and that such modulation may provide a mechanism of action for many of their therapeutic effects." Use garlic daily in all your favorite dishes, or consider taking garlic extract during flu season.

7. Apples

It's what they say about an apple a day. The fruit we grew up with and is the first letter of the alphabet has soluble fiber, which has been shown to reduce inflammation and boost the immune system's response to infection. Inflammation slows the immune system's response, lab animals given soluble fiber (found in apples, oats, and nuts, as well as most leafy vegetables) can reduce symptoms and speed recovery time when illness strikes, according to Science Daily, based on a study from the University of Illinois.

Do eat the skin of the apple, which some people discard because it may carry pesticides. But for your immune system, the skin should be washed but not discarded, since it contains vitamins K, A, and C, which all help boost immunity and fight off infection. Vitamin K plays a key role in different blood functions including coagulation, bone metabolism, and the regulation of some enzyme systems. Vitamin K acts as a "cofactor" in building up plasma, which helps the body's immune and inflammatory responses. Studies have found links between vitamin K levels and diseases, including inflammatory diseases, including heart disease and cancer.

What to drink to fight off colds and flu

Drink these 4 Teas: Ginger, Ginseng, Green, and Turmeric

Tea is always a good idea when a scratchy throat arises. It can soothe the symptoms but also go to the root of what is creating that immune response. Here are the four types of teas that boost your immune system and help fight inflammation, oxidation, and infection.

1. Ginger Tea lowers inflammation, and acts as an anti-oxidative in the body, according to a review, and that allows the immune system to operate without having to worry about "other" inflammation or cellular damage in the system, which can act like a traffic jam impeding the progress of a fire truck. In scientific terms, oxidation causes cellular aging, which can lead to cancer, so ginger is now considered an anti-cancer food. "The anticancer potential of ginger is well documented and its functional ingredients like gingerols, shogaol, and paradols are the valuable ingredients which can prevent various cancers," the study concluded.

2. Ginseng Tea keeps the cytokine response in check. Ginseng has been shown to help the immune system fight off colds and flu. The science has found: "Ginseng has been extensively reported to maintain homeostasis of the immune system and to enhance resistance to illness or microbial attacks through the regulation of the immune system."

How it does this: When the immune system responds to invaders, cytokines are mobilized, sometimes too much which gives rise to the cytokine storm – an overreaction that creates an inflammatory response that can actually hamper the lungs and your body's ability to clear away the invaders.

Studies have shown that ginseng controls proinflammatory cytokine responses, to allow the T-killer cells and natural killer cells to do their jobs, unimpeded by the "panic" of overly-zealous cytokine cells. For the best dosage, look for 200 to 400 milligrams of ginseng extract, or make herbal ginseng tea and drink it daily.

3. Green Tea has powerful antioxidants that help your body fight off colds and flu, according to studies. Two of these disease-fighting polyphenols are EGCG and catechins, but green tea also contains other compounds that studies show have antiviral properties and could offer protection against infections.

In one study that examined the "Immunomodulating effects of epigallocatechin-3-gallate [EGCG]  from green tea: mechanisms and applications, EGCG appears to lower inflammation, boost energy, and even help the body burn fat." The effects on the immune system are direct and indirect since studies show that obesity-related diseases and inflammation both suppress the body's immune response.

This particular study found: "Consuming green tea or its active ingredient, epigallocatechin-3-gallate [EGCG] has been shown consistently to benefit the healthy functioning of several body systems. In the immune system specifically, accumulating evidence has revealed an immunomodulating effect of green tea or EGCG. Several types of immune cells in both the innate and adaptive immune systems are known to be affected in varying degrees by green tea/EGCG. Among them, the dramatic effect on T cell functions has been repeatedly demonstrated, including T cell activation, proliferation, differentiation, and production of cytokines."

4. Turmeric Tea can actually prevent you from getting sick, studies show. Turmeric tea is a powerful immune booster that has been shown to not only reduce the symptoms of a cold or flu if you get sick but also protect you from getting sick in the first place. A study found that curcumin, the active ingredient in turmeric, is traditionally known for its anti-inflammatory effects. But "curcumin has been shown in the last two decades to be a potent immunomodulatory agent that can modulate the activation of T cells, B cells, macrophages, neutrophils, natural killer cells, and dendritic cells," according to the scientists.

While it is helping the immune system, it is also fighting off longer-term disease, the researchers have found: "Curcumin’s reported beneficial effects in arthritis, allergy, asthma, atherosclerosis, heart disease, Alzheimer’s disease, diabetes, and cancer might be due in part to its ability to modulate the immune system."

Bottom Line: Eat these 7 foods and drink these 3 teas to fight off colds and flu

Pile on plant-based foods like vegetables, fruit, nuts, and seeds and lower inflammation in the body to help your immune system fight off colds and flu. Your best bet to avoid getting sick this winter is to eat more spinach, broccoli, blueberries, oranges, apples, and garlic as often as you can and add tea – especially ginger, ginseng, green, and turmeric – to the mix.