Nourish Your Immune System (FN1773, Reviewed Nov. 2019)

Our immune system functions throughout our body. It is composed of specialized cells that prevent or limit infection in our bodies. Immune cells recognize substances that enter our bodies and attempt to remove them if the substance appears to be harmful to us.

Julie Garden-Robinson, Ph.D., R.D., L.R.D. Food and Nutrition Specialist

Allison Dhuyvetter, R.D., Program Assistant

Availability: Web only

Tuna on a fork


Consuming a healthful diet is one of the best strategies for having a healthy immune system. Research has shown some nutrients, including protein, and certain vitamins and minerals, have specific roles in immune health. If we lack any of these nutrients, our ability to fight infection can decrease.


Protein is found in every cell, tissue and organ in our bodies. When we do not get enough protein, our bodies may produce less of certain immune cells and increase our susceptibility to infections of the respiratory, gastrointestinal and urinary tract. Protein foods include chicken, beef, pork, fish, eggs, peanut butter, milk, seeds, beans and nuts.

Tip: Include lean protein such as chicken, beans and eggs at each meal to get enough protein for the day. Adult women age 19 and older should get about 46 grams (g) of protein per day and adult men should get about 56 g per day. Check out the table below to see how many grams of protein
are found in certain foods.

Protein Content of Selected Foods

24g  3 ounces lean beef
22g  3 ounces salmon, tuna or halibut
16g  3 ounces lean chicken
15g  1 cup black beans
14g  1 cup plain non-fat yogurt
9g    1 ounce nonfat mozzarella cheese
8g    1 cup milk
6g    1 ounce almonds (about 23)
6g    1 large egg

What are some good sources of antioxidant nutrients? Which ones do you consume regularly?


Food Sources

Vitamin A keeps the skin and tissues of the mouth, stomach, intestines and respiratory system healthy. These tissues serve as our first line of defense against infection.


Carrots, apricots, sweet potatoes, kale, spinach, red bell peppers and eggs

Vitamin C helps with the formation of antibodies and the production of certain immune cells.


Oranges, grapefruit, tangerines, red bell pepper, papaya, strawberries, kiwi, tomato juice and foods fortified with vitamin C, such as some cereals

Vitamin E protects cell membranes in the body.


Sunflower seeds, almonds, and oils such as sunflower and safflower oil

Selenium deficiency has been shown to decrease immune cells’ disease-fighting power.


Selenium is a mineral found in the soil. We get selenium from the animals and plants we eat.

Test Your Knowledge

Which food is high in vitamin C?

A. Beets
B. Red bell pepper
C. Eggs
D. Oatmeal

Answer: B. Red bell pepper

Vitamin D

When our body is low in vitamin D, we are less able to fight off infection and disease. The best way to get vitamin D is to absorb it from the sun. Unfortunately, for the states in the northern part of the U.S., the sun is only strong enough for our bodies to absorb vitamin D from March to October.

Test Your Knowledge

How much vitamin D does an adult between the ages of 19 and 70 need each day?

A. 2,000 IU
B. 800 IU
C. 600 IU

Answer: C. 600 IU

Other Nutrients and Sources

What are some other immune system-friendly nutrients and their food sources?


Food Sources

Recommended Intake

Vitamin D


Milk, oily fish such as tuna and salmon, mushrooms, breads, yogurt and orange juice

600 IU/day adults more than19 years old

B6, folate and vitamin B12 are important for immune cell growth.


Tuna, turkey, beef, chicken, salmon, sweet potatoes, sunflower seeds and bananas

1.3 to 1.7 mg/day adults more than 19 years old



Spinach, broccoli, beans, lentils, asparagus, avocado, orange juice and fortified cereals

400 mcg/day adults more than 19 years old



Sardines, salmon, tuna, cod, lamb, scallops, shrimp and beef

2.4 mcg/day adults more than 19 years old


Food Sources

Recommended Intake

Iron deficiency has been associated with reduced immunity in human and animal studies. Our bodies can absorb iron better when it’s paired with a food high in vitamin C, such as a citrus fruit, bell pepper or broccoli.


Red meat, pork, poultry, beans, seafood, spinach, and iron-fortified breads, cereals and pastas

8 mg/day males more than19 years old

18 mg/day females 19 to 50 years old

8 mg/day females more than 50 years old


Zinc deficiency can affect how certain immune cells function.


Lean meat, poultry, seafood, milk, whole grain products, beans and nuts

11 mg/day males more than19 years old

8 mg/day females more than19 years old

Test Your Knowledge

Circle the nutrients that are good for immune health.

Antioxidants Vitamin D Alcohol Copper Iron Niacin Zinc Protein

Answer: antioxidants, vitamin D, iron, zinc, protein

Healthy Lifestyle, Healthy Body

Get Healthy!

To have a healthy, strong immune system, we need to focus on getting healthy overall. Here are a few lifestyle factors that can impact your immune health.

Exercise: Participate in regular physical activity. Regular activity can benefit your entire body by helping you maintain a healthy body weight. Exercise also can keep you in good health, which allows your immune system to work properly. Aim to get at least 30 minutes of activity a day three to five times per week.

Manage stress: Certain types of stress can weaken our immune system and make us more susceptible to infection. Get enough sleep, manage your blood pressure and focus on leading a healthy lifestyle. Sleep deprivation can depress the immune system’s disease-fighting power by reducing the production of T cells.

Limit alcohol: Alcohol is one substance that can suppress our immune system. If you do drink, drink in moderation. Moderation is defined as one drink a day for women and two drinks a day for men.

Did you know?

One drink is considered to be 5 ounces of wine, 12 ounces of beer or 1.5 ounces of 80-proof spirits.

Take steps to avoid infection: Wash your hands frequently. Practice food safety when preparing food at home to reduce the spread of bacteria. Wash fruits and vegetables before eating. Thaw food in the refrigerator, in cold water or in the microwave. Cook meat and seafood thoroughly, and
keep raw and cooked foods separate.

__________________ is one of the best ways to avoid infections and help keep your immune system healthy.

Answer: Handwashing

Foods to Limit

Not all foods are good for the immune system. Fatty foods and alcohol can suppress the immune system and make us more susceptible to infection. Also, foods eaten in excess can lead to obesity, which can cause immune system function to be reduced.

More Information:

Academy of Nutrition and Dietetics

National Institute of Allergy and Infectious Diseases

Harvard Health Publications


Nutrient: anything that nourishes the body; we get nutrients from the foods we eat

Antibodies: a protein made by the body that produces an immune response when it senses an invader

Antioxidant: a substance that inhibits oxidation or reactions promoted by oxygen

More Information

Centers for Disease Control and PreventionU.S. Department of Health and Human Services

This project is supported by the Rural Health & Safety Education Competitive Grant Program of the USDA National Institute of Food and Agriculture (NIFA), grant number 2013-46100-21467.


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