Eat Well to Boost Your Immune System

Immune Boosting Breakfast: 8 fresh fruits ,mixed berry compote , kefir and yogurt. Photo by Lorelle Del Matto

With the Covid-19 virus in our midst, everyone wants a robust immune system.

March is National Nutrition Month, an opportune time to promote the huge role a balanced, nutrient-packed diet plays in supporting a healthy immune system. Here’s a simple explanation from Harvard Health Publishing, How to boost your immune system (1):

“Like any fighting force, the immune system army marches on its stomach. Healthy immune system warriors need good, regular nourishment.”

My favorite tip in the article is: eat a diet high in fruits and vegetables. The greater diversity and quantity of produce you eat, the more likely you are to get the vitamins, minerals, antioxidants and other phytochemicals you need to help fight off infections and, if you do get sick or injured, help you heal readily and prevent complications (2,3,4).

The dietary fiber and other indigestible components of fruits, veggies (and other plant foods – legumes, grains and nuts) support immunity by helping with healthy digestion. Most immune cells are in the digestive tract (2,4). The dietary fiber and other indigestible components in plant foods nourish the microbiota or good bacteria in the gut, aid in the digestion and absorption of nutrients, and help fend off bacteria and viruses we don’t want (4),

I’d never eat enough fruit if I didn’t have a morning ritual cutting up a container of 7 to 8 fresh fruits every morning with my latte. It’s ready to eat for breakfast or when I crave a sweet, juicy snack.

Beyond a foundation of fruits and vegetables, good health and a robust immune system needs a symphony of macro- and micro-nutrients that work synergistically, including (2,3,4):

  • Quality protein to build cells
  • Plant-based oils and omega-3 fatty acids abundant in oily fish
  • B vitamins and minerals from an array of foods
  • vitamin D from fatty fish, egg yolks, some light-exposed mushrooms and fortified foods (4)
Photo by Lorelle Del Matto

I start my day with protein- and probiotic- rich Greek yogurt and kefir, which contain live, active “good” bacteria and yeasts that may help the body’s immune response by maintaining a robust population of gut microbes (5). For more, check out my post, Get the Most from Probiotic-Rich Foods.  

Calling berries superfoods is not an overstatement. They, are rich in antioxidants such as vitamins A, C, E and anthocyanins, pigments that give them red, purple and blue colors. Berry research shows they support gut health, immunity and reduce the risk of cardiovascular disease and other conditions (7).

I eat berries daily. To minimize shopping trips, I bought a huge bag of frozen mixed berries and cooked them into a compote to jazz up my yogurt.  

Balance cooked fruit and veggies with fresh. Some nutrients are reduced with cooking, such as vitamin C. Other nutrients, such as the carotenoid lycopene found in tomatoes, become more bioavailable, or useful to the body, when cooked (4,8). Canned and dried are fine, too.

Why are antioxidants so important? Antioxidants prevent oxidative stress by scavenging free radicals that the body produces as it digests and processes food and reacts to substances in the environment, such as pollution, other toxins and smoking. Oxidative stress is linked to immune deficiency and can increase inflammation and the risk of diseases like heart and vascular conditions, arthritis, cognitive loss, type II diabetes and certain cancers (6,7).

Other lifestyle practices that support your immune system (1):  

  • Don’t smoke.
  • Exercise regularly.
  • Maintain a healthy weight.
  • If you drink alcohol, drink only in moderation.
  • Get adequate sleep.
  • Take steps to avoid infection, such as washing your hands frequently and cooking meats thoroughly.
  • Try to minimize stress.

Only a 1 in 10 Americans get enough fruits and vegetables so we need to find ways to fit them in (9). Eating fruit is easy. It’s arguably best raw, and requires little prep. Who can’t peel a banana? Eat a colorful rainbow of plants to maximize your intake of potent phytonutrients.

Get kids used to eating produce by including a fruit or veggie at every meal and snack. That strategy worked well with my kids.

How much is enough? Adults need at least 1 ½ to 2 cups of fruit and 2 ½ to 3 cups of vegetables according to the U.S. Dietary Guidelines for Americans, 2015-2020 (children need less). Be a superstar and shoot for 9 to 10 servings, an amount research has shown is optimal (10).


  1. How to boost your immune system. Harvard Health Publishing.2
  2. Diet and immune function. Nutrients. 2019 Aug; 11(8): 1933.  Caroline E. Childs,1 Philip C. Calder,1,2 and Elizabeth A. Miles. 3
  3. Understanding nutrition and immunity in disease management. Edwin L. Cooper and Melissa J. Ma. Journal of Traditional and Complementary Medicine. Oct; 7(4): 386–391. 4
  4. Staying Healthy with Immune Boosting & Anti-inflammatory Foods. Kate Ueland MS, RD. 5
  5. Probiotics: What You Need To Know. National Center for Complementary and Integrative Health.6
  6. Recent Research on the Health Benefits of Blueberries and Their Anthocyanins. Wilhelmina Kalt, Aedin Cassidy, Luke R Howard, Robert Krikorian, April J Stull, Francois Tremblay, Raul Zamora-Ros. Advances in Nutrition, Volume 11, Issue 2, March 2020, Pages 224–236.  7
  7. How can antioxidants protect our health? Megan Ware, RDN, L.D Medically reviewed by Natalie Olsen, R.D., L.D. Medical News Today. May 29, 2018.8
  8. Foods, Not Supplements. Tuft’s Health & Nutrition Letter. November 2019. Vol 37, No. 9.9
  9. 2018 Fruit and Vegetable Report. Centers for Disease Control and Prevention. 10
  10. About the Buzz: Eat 10 Servings of Fruits and Vegetables Per Day?

© Lorelle Del Matto 2020

lorelle About lorelle

Crazy about cooking, eating and sharing good food – my work and leisure revolve around the kitchen. As a culinary dietitian my professional life encompasses nutrition counseling and education, recipe development, product development, food and nutrition writing, marketing communications, corporate test kitchen and consumer affairs management, food styling and work as a product spokesperson.


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