With everything going on these days, it doesn’t hurt to add as many of these foods into your diet as possible. For cancer patients, it is particularly important to keep your immune system protected and boosted with good healthy foods.
Medically reviewed by Amy Richter, RD — Written by James Schend — Updated on April 30, 2020
Immune system boosters
Feeding your body certain foods may help keep your immune system strong.
If you’re looking for ways to prevent colds, the flu, and other infections, your first step should be a visit to your local grocery store. Plan your meals to include these 15 powerful immune system boosters.
1. Citrus fruits
Most people turn straight to vitamin C after they’ve caught a cold. That’s because it helps build up your immune system.
Vitamin C is thought to increase the production of white blood cells, which are key to fighting infections.
Almost all citrus fruits are high in vitamin C. With such a variety to choose from, it’s easy to add a squeeze of this vitamin to any meal.
Popular citrus fruits include:
Because your body doesn’t produce or store it, you need daily vitamin C for continued health. The recommended daily amount for most adults is:
- 75 mg for women
- 90 mg for men
If you opt for supplements, avoid taking more than 2,000 milligrams (mg) a day.
Also keep in mind that while vitamin C might help you recover from a cold quicker, there’s no evidence yet that it’s effective against the new coronavirus, SARS-CoV-2.
2. Red bell peppers
If you think citrus fruits have the most vitamin C of any fruit or vegetable, think again. Ounce for ounce, red bell peppers contain almost 3 times as much vitamin C (127 mgTrusted Source) as a Florida orange (45 mgTrusted Source). They’re also a rich source of beta carotene.
Besides boosting your immune system, vitamin C may help you maintain healthy skin. Beta carotene, which your body converts into vitamin A, helps keep your eyes and skin healthy.
Broccoli is supercharged with vitamins and minerals. Packed with vitamins A, C, and E, as well as fiber and many other antioxidants, broccoli is one of the healthiest vegetables you can put on your plate.
The key to keeping its power intact is to cook it as little as possible — or better yet, not at all. ResearchTrusted Source has shown that steaming is the best way to keep more nutrients in the food.
Garlic is found in almost every cuisine in the world. It adds a little zing to food and it’s a must-have for your health.
Early civilizations recognized its value in fighting infections. Garlic may also slow down hardening of the arteries, and there’s weak evidence that it helps lower blood pressure.
Garlic’s immune-boosting properties seem to come from a heavy concentration of sulfur-containing compounds, such as allicin.
Ginger is another ingredient many turn to after getting sick. Ginger may help decrease inflammation, which can help reduce a sore throat and inflammatory illnesses. Ginger may help with nausea as well.
While it’s used in many sweet desserts, ginger packs some heat in the form of gingerol, a relative of capsaicin.
Ginger may also decrease chronic painTrusted Source and might even possess cholesterol-lowering propertiesTrusted Source.
Spinach made our list not just because it’s rich in vitamin C — it’s also packed with numerous antioxidants and beta carotene, which may both increase the infection-fighting ability of our immune systems.
Similar to broccoli, spinach is healthiest when it’s cooked as little as possible so that it retains its nutrients. However, light cooking makes it easier to absorb the vitamin A and allows other nutrients to be released from oxalic acid, an antinutrient.
Look for yogurts that have the phrase “live and active cultures” printed on the label, like Greek yogurt. These cultures may stimulate your immune system to help fight diseases.
Try to get plain yogurts rather than the kind that are flavored and loaded with sugar. You can sweeten plain yogurt yourself with healthy fruits and a drizzle of honey instead.
Yogurt can also be a great source of vitamin D, so try to select brands fortified with this vitamin. Vitamin D helps regulate the immune system and is thought to boost our body’s natural defenses against diseases.
Clinical trials are even in the works to study its possible effects on COVID-19.
When it comes to preventing and fighting off colds, vitamin E tends to take a backseat to vitamin C. However, this powerful antioxidant is key to a healthy immune system.
It’s a fat-soluble vitamin, which means it requires the presence of fat to be absorbed properly. Nuts, such as almonds, are packed with the vitamin and also have healthy fats.
Adults only need about 15 mg of vitamin E each day. A half-cup serving of almonds, which is about 46 whole, shelled almonds, provides around 100 percentTrusted Source of the recommended daily amount.
9. Sunflower seeds
Sunflower seeds are full of nutrients, including phosphorous, magnesium, and vitamins B-6 and E.
Vitamin E is important in regulating and maintaining immune system function. Other foods with high amounts of vitamin E include avocados and dark leafy greens.
Sunflower seeds are also incredibly high in selenium. Just 1 ounce contains nearly halfTrusted Source the selenium that the average adult needs daily. A variety of studies, mostly performed on animals, have looked at its potential to combat viral infections such as swine flu (H1N1).
You may know turmeric as a key ingredient in many curries. This bright yellow, bitter spice has also been used for years as an anti-inflammatory in treating both osteoarthritis and rheumatoid arthritis.
ResearchTrusted Source shows that high concentrations of curcumin, which gives turmeric its distinctive color, can help decrease exercise-induced muscle damage. Curcumin has promise as an immune booster (based on findings from animal studies) and an antiviral. More research is needed.
11. Green tea
Both green and black teas are packed with flavonoids, a type of antioxidant. Where green tea really excels is in its levels of epigallocatechin gallate (EGCG), another powerful antioxidant.
In studies, EGCG has been shown to enhance immune function. The fermentation process black tea goes through destroys a lot of the EGCG. Green tea, on the other hand, is steamed and not fermented, so the EGCG is preserved.
Green tea is also a good source of the amino acid L-theanine. L-theanine may aid in the production of germ-fighting compounds in your T cells.
Papaya is another fruit loaded with vitamin C. You can find doubleTrusted Source the daily recommended amount of vitamin C in a single medium fruit. Papayas also have a digestive enzyme called papain that has anti-inflammatory effects.
Papayas have decent amounts of potassium, magnesium, and folate, all of which are beneficial to your overall health.
Like papayas, kiwis are naturally full of a ton of essential nutrients, including folate, potassium, vitamin K, and vitamin C.
Vitamin C boosts the white blood cells to fight infection, while kiwi’s other nutrients keep the rest of your body functioning properly.
When you’re sick and you reach for chicken soup, it’s more than just the placebo effect that makes you feel better. The soup may help lower inflammation, which could improve symptoms of a cold.
Poultry, such as chicken and turkey, is high in vitamin B-6. About 3 ounces of light turkey or chicken meat contains nearly one-third of your daily recommended amount of B-6.
Vitamin B-6 is an important player in many of the chemical reactions that happen in the body. It’s also vital to the formation of new and healthy red blood cells.
Stock or broth made by boiling chicken bones contains gelatin, chondroitin, and other nutrients helpful for gut healing and immunity.
Shellfish isn’t what jumps to mind for many who are trying to boost their immune system, but some types of shellfish are packed with zinc.
Zinc doesn’t get as much attention as many other vitamins and minerals, but our bodies need it so that our immune cells can function as intended.
Varieties of shellfish that are high in zinc include:
Keep in mind that you don’t want to have more than the daily recommended amount of zinc in your diet:
- 11 mg for adult men
- 8 mg for most adult women
Too much zinc can actually inhibit immune system function.
More ways to prevent infections
Variety is the key to proper nutrition. Eating just one of these foods won’t be enough to help fight off the flu or other infections, even if you eat it constantly. Pay attention to serving sizes and recommended daily intake so that you don’t get too much of a single vitamin and too little of others.
Eating right is a great start, and there are other things you can do to protect you and your family from the flu, cold, and other illnesses.
Start with these flu prevention basics and then read these 7 tips for flu-proofing your home. Perhaps most importantly, get your annual flu vaccine to protect yourself and others.