Senior couple cooking healthy food in kitchen.

Know the ABCs for boosting your immune system

When it comes to eating the right foods to boost your immune system, it can be as easy as the ABCs.

Kaela Ketcham, a clinical dietitian with the OSF HealthCare Saint Francis Medical Center Weight Management Center at the RiverPlex in Peoria, said vitamin A, beta carotene, vitamins C, D, E and zinc make up the alphabet for boosting your immune system.

Getting the recommended daily allowance (RDA) of those vitamins and nutrients will help to keep you healthy.

Vitamin A

Vitamin A helps with the immune system as a whole and in the functioning of the heart, lungs, kidneys and other organs. “Really what it does is cell growth,” Kaela said. Foods high in vitamin A include:

  • Eggs
  • Fish
  • Dairy products

The RDA is:

  • Females – 700 micrograms
  • Males – 900 micrograms


  • 1 cup yogurt has 32 micrograms
  • 1 egg has 75 micrograms
  • 3 ounces of salmon has 60 micrograms

Beta carotene

Beta carotene goes hand in hand with vitamin A. “It’s called a provitamin and just becomes vitamin A as the body needs it,” Kaela said. Foods high in beta carotene include:

  • Plant-based food

While there is a RDA for Vitamin A, there is no RDA for beta carotene.


  • 1 sweet potato has 1,400 micrograms
  • ½ cup raw carrots has 460 micrograms
  • ½ cup cooked spinach has 570 micrograms

Vitamin C

Vitamin C aids in healing and boosting the immune system. Foods high in vitamin C include:

  • Citrus fruits
  • Berries
  • Peppers
  • Broccoli

The RDA is:

  • Female – 75 milligrams a day
  • Male – 90 milligrams a day


  • ½  cup raw bell peppers has 95 milligrams
  • 1 medium raw orange has 70 milligrams
  • ½ cup cooked broccoli has 50 milligrams
  • ½ cup strawberries has 50 milligrams

Vitamin D

Vitamin D helps with boosting the immune system, along with aiding our bones. Kaela said vitamin D is not as common in foods, but can be found in:

  • Fatty fish
  • Eggs
  • Fortified foods such as fortified milk, cereal and juices – which  means vitamin D has been added to the product

The RDA is:

  • Over the age of 1 – 15 micrograms a day until age 70, then 20 micrograms a day due to those that age likely spend more time indoors and potentially are not eating as much
  • Infants up to age 1 – 10 micrograms a day


  • 3 ounces of salmon has 14 micrograms
  • 1 cup milk has 3 micrograms
  • 1 egg has 1 microgram

“Vitamin D comes from the sunshine, too,” Kaela said. “It’s suggested that 5 to 30 minutes of exposure to the sun to the face, arms, legs or back during 10 a.m. and 3 p.m. twice a week would be enough to provide you with the vitamin D your body needs.”

Vitamin E

Vitamin E is helpful with the immune system. It is found in:

  • Oil

The RDA is:

  • Age 1-3 – 6 milligrams a day
  • Age 4-8 – 7 milligrams a day
  • Age 9-13 – 11 milligrams a day
  • Over the age of 14 – 15 milligrams a day


  • 1 ounce of almonds has 7 milligrams
  • 1 ounce of sunflower seeds has 7 milligrams
  • 2 tablespoons of peanut butter has 3 milligrams
  • 1 tablespoon of soybean oil has 1 milligram
  • 1  tablespoon of sunflower oil has 6 milligrams
  • 1 tablespoon of corn oil has 2 milligrams


Zinc does a lot of different things with cells, but it also helps with the immune system and in healing,” Kaela said. Zinc can be found in:

  • Meat
  • Dairy products
  • Grains

The RDA is:

  • Females age 14 and older – 8 milligrams a day
  • Males age 14 and older – 11 milligrams a day
  • Children age 1-3 – 3 milligrams a day
  • Children 4-8 – 5 milligrams a day
  • Children 9-13 – 8 milligrams a day


  • 3 ounces of chuck roast has 7 milligrams
  • 3 ounce pork chop has 3 milligrams
  • 1 cup low-fat milk has 1 milligram

Variety is the key

“A lot of the vitamins you need are in different foods, that’s why it’s important to get a wide variety of food groups in your diet each day,” Kaela said. “If we’re eliminating one or more food group we’ll be missing out on nutrients that will help with our immune system.”

What about supplements?

“Meeting with a dietitian can help determine if a supplement is needed or if your diet is providing you with the nutrients you need,” Kaela said. “Before starting any supplements, talk to your doctor to make sure a supplement won’t cause any interaction with any medication you are currently taking.”

The No. 1 goal

“The more nutrients you can get from food the better,” she said. “Food gives you more bang for your buck when it comes to getting the nutrients your body needs to stay healthy.”

Last Updated: April 22, 2021

Follow Us on Social Media

About Author: Lisa Coon

Lisa Coon is a Writing Coordinator for OSF HealthCare, where she has worked since August 2016.  A Peoria native, she is a graduate of Bradley University with a degree in journalism. Previously, she worked as a reporter and editor at several newspapers in Iowa and Illinois.

She lives in Groveland with her husband and son. In her free time she likes to cook, bake and read. She freely admits that reality TV is a weakness, and she lives by the quote, “The beach is good for the soul.”

View all posts by

Tags: , , ,

Categories: Diet & Exercise