To help maximize your immune system’s ability to fight infection, eating a balanced diet with a wide variety of foods can help you get all of the nutrients your body needs to function optimally.

Although the body’s systems are interconnected, and getting all nutrients is important, some nutrients are used more directly for immune system support. These include:

Vitamin A

Vitamin A supports the health of the skin, eyes, respiratory, and digestive systems to maintain barriers against pathogens. Vitamin A is also required for immune cells that generate antibodies.  

Foods rich in vitamin A:

• Sweet potatoes, carrots, pumpkin
• Dark leafy greens
• Liver, other animal organs
• Egg yolks
• Fortified dairy

Vitamin C

Vitamin C has direct antioxidant effects and assists enzymes that regenerate vitamin E into its antioxidant form. 

Foods Rich in Vitamin C

• Citrus
• Kale
• Kiwi
• Cauliflower

Vitamin D

Vitamin D supports immune function by promoting antibacterial responses and modulating T-cell function. Very few foods contain vitamin D making it difficult for many people to meet the daily requirement.

Good sources of vitamin D:

• Sunlight
• Fortified milk, Fortified OJ
• Fatty fish (salmon, mackerel, sardines)
• Mushrooms (UV light exposed)

Vitamin E

Vitamin E acts as an antioxidant that protects important lipids and cell membranes. It supports immune cells by protecting their membranes and reducing things that suppress the immune system. 

Foods rich in vitamin E:

• Avocado
• Nuts
• Seeds
• Vegetable oils

Selenium

Selenium supports antioxidant enzymes in the body, including glutathione peroxidase and thioredoxin reductase, that protect immune cells from damage.  It also influences chemical messengers that regulate immune cell function and inflammation. 

Foods rich in selenium:

• Brazil nuts and other nuts
• Oysters, mussels, clams, fish
• Liver, poultry, meats
• Wheat, oats, barley
• Chia and sunflower seeds

Copper

Copper is a critical component of the antioxidant enzyme in the body called SOD (superoxide dismutase), which protects immune cells from compounds that are generated to kill pathogens during an immune response. 

Foods rich in copper

• Fish and shellfish
• Nuts and seeds
• Lentils, soybeans
• Chocolate
• Kale

Zinc

Zinc is needed for hundreds of essential proteins involved in immune function, and it is required for the growth and development of immune cells. Zinc assists in the creation of antibodies and is needed for several antioxidant enzymes, including SOD. Vitamin A transporters also require zinc.

Foods rich in zinc:

• Meats and liver
• Fish and shellfish
• Eggs
• Nuts and seeds
• Cereals and grains

Manganese

Manganese is required for an essential antioxidant enzyme (MnSOD) found in high amounts in the mitochondria (the energy-producing part of the cell). MnSOD helps to protect cells from oxidative damage.

Foods rich in manganese:

• Liver
• Chickpeas
• Nuts and seeds
• Shellfish
• Whole grains and cereals
• Quinoa
• Peanuts

Magnesium

Magnesium is part of hundreds of reactions in the body that support the immune system, including energy production, DNA and protein synthesis, and cell communication. Magnesium is required to stabilize ATP (primary energy molecule in the body) and is necessary to synthesize glutathione, an important antioxidant enzyme in the body.

Foods rich in magnesium:

• Nuts and seeds
• Legumes (e.g., beans, lentils, soybeans)
• Cereals and whole grains/products
• Milk
• Dark leafy greens
• Dark chocolate

Iron

Iron supports the immune system as a necessary part of catalase and some peroxidases.  These enzymes protect cells against the accumulation of hydrogen peroxide used by white blood cells to kill pathogens. Iron is also needed for T lymphocyte production.

Foods rich in iron:

• Liver, meats, poultry
• Oysters, fish, seaweed
• Whole and fortified grains and cereals
• Potatoes
• Lentils, beans
• Soybeans
• Dark chocolate
• Nuts, seeds
• Dark leafy vegetables

B vitamins

B vitamins are involved in hundreds of reactions that are critical to cell function, including supporting immune cells by assisting in energy and DNA production.  Vitamin B6 also promotes lymphocyte and IL-2 production.  

Foods rich in B vitamins:

• Whole and fortified grains products (pasta, bread, rice) and cereals
• Pork
• Beans, peanuts, lentils
• Dairy
• Almonds
• quinoa
• Avocado
• Sunflower seeds
• OJ

Molybdenum

Molybdenum is involved in immune defense by supporting an antioxidant enzyme. It also supports systems that detoxification of drugs and other toxins.

Foods rich in molybdenum:

• Liver
• Legumes (beans, lentils, soybeans, peanuts)
• Whole grains
• Nuts

Omega-3 fats

Omega-3 fats, including EPA and DHA, are essential fats that promote antioxidant-like effects during an immune response. These fats are not made by the body and are critical to be in the diet.

Foods rich in omega-3s:  

• Flaxseeds, flaxseed oil, and chia seeds
• Walnuts and walnut oil
• Canola and soybean oils
• Herring, salmon, tuna, crab, and oysters
• Krill, fish, cod liver (caution with the vitamin A dose), and some algae oils

Arginine and glutamine

Arginine and glutamine are amino acids that are used in high amounts during illness.

Arginine plays a critical role in the immune system, including affecting T-lymphocyte function and nitric oxide production.

Glutamine is the preferred fuel source for rapidly dividing cells, such as immune cells during infection. Glutamine exerts many protective effects during critical illnesses, such as helping the intestinal cells maintain a barrier to pathogens.

Both amino acids and have supportive research behind their use during critical illnesses. 

Under most conditions, the body is able to make these amino acids.  However, during illness, these can become conditionally essential, meaning the body cannot make enough on its own. 

Ensuring adequate protein intake, particularly during illness, assists the body in meeting metabolic demands.

Good sources:

• Meats, poultry, fish
• Dairy
• Eggs
• Pumpkin seeds
• Legumes (lentils, peanuts, chickpeas, soybeans)

Phytonutrients

Phytonutrients include thousands of plant compounds that have much research to support antioxidant, anti-inflammatory, and other protective effects in the body.  They include, but are not limited to:

• Carotenoids, such as beta-carotene, an orange-red pigment in plants
• Flavonoids like resveratrol in red wine and catechins in green tea
• Isoflavones in soy

Good sources:

• Red, orange, and yellow fruits and veggies (citrus, pumpkin, corn)
• Dark green leafy vegetables (kale, spinach, lettuce)
• Green tea
• Red wine
• Soy
• Turmeric
• Berries
• Garlic
• Cruciferous veggies (cauliflower, broccoli, bok choy, cabbage, Brussels sprouts)

How much of each nutrient do you need?

Check out our nutrition section for more information on each nutrient.

Summary

Proper nutrition is necessary for the body to defend itself against pathogens. The easiest way to do this is to eat a wide variety of foods, especially plants.

If you do get sick, you might not feel well enough to eat.  So snacking on foods mentioned and getting adequate protein and fluids (requirements increase) can help support your immune system when it is using up these resources quickly.

See our Cautionary Note on Supplements.

Content presented here, although created by US Registered Dietitians and PhD-level Nutritional Biologists, is for informational purposes only and is not intended to be medical advice. Consult your health care provider before using any supplements or making dietary changes.