Boost Your Immune System to Fight Off Illness

Simple dietary and lifestyle tips to strengthen your immune system and help keep you healthy

Food & Nutrition

As COVID-19 has hit people of all ages, many of us are wondering what we can do to boost our immune system to help fight off COVID and other common illnesses. While there’s a lot of information at our fingertips, it can be hard to tell fact from fiction.

First and foremost, does having a strong immune system help prevent illness?

In a word: Yes.

“Whether a virus or bacteria, your body is being attacked by something and it needs to fight it,” says Kristin Gustashaw, MS, RDN, LDN, CSG, clinical dietitian and nutrition consultant at Rush University Medical Center. “Between a strong immune system and healthy diet, your well-oiled machine is going to allow you to better take any hit from a virus or cold.”

An unbalanced diet is one way your body develops immune-related deficiencies, leading to greater health risks and longer recovery times. 

Nutritional deficiencies, or micronutrient deficiencies, happen when you’re not getting enough of the essential vitamins or minerals needed for optimum health and immunity. And this is a common challenge among people of all ages.

So how do we make sure we’re addressing or avoiding these deficiencies? 

Zinc and COVID-19

Zinc was found to help some patients with COVID-related hospitalizations — specifically those who were malnourished, with dietary deficiencies — a common challenge with elderly or chronically ill patients.

As COVID-19 began to spread, many people increased their zinc intake with over-the-counter remedies, such as Zicam tablets. While certain forms of zinc have been found to help reduce the severity of symptoms and duration of the common cold, it is unclear if taking zinc will help prevent or reduce symptoms of COVID-19 if you are not deficient.

Unfortunately, taking zinc supplements for extended periods of time can cause more harm than good. “Too much zinc in your system can cause the mineral to compete for absorption with other vitamins or minerals, such as copper,” says Kelly Roehl, MS, RDN-AP, LDN, CNSC, nutrition support dietitian at Rush.

“And if your body isn’t absorbing enough copper, it can cause nervous system and blood glucose problems,” she adds. “Instead, it’s best to follow a diet adequate in zinc.”

You typically can get all the zinc you need by simply incorporating red meat, poultry, beans, nuts, whole grains and breakfast cereals with added zinc into your regular diet.

Immune system health is more important than ever with new viruses like COVID-19.

The importance of sun and vitamin D

Another important factor in maintaining a strong immune system is vitamin D.

“Vitamin D should really be referred to as a hormone, since no natural food source can provide adequate amounts and, much like hormones, it’s made in one part of the body and acts on another,” says Roehl. “Vitamin D enhances multiple areas of cellular immunity, especially the body’s inflammatory response.”

So how do we get enough vitamin D? In Illinois, between late April and early October, you can make adequate amounts of vitamin D by spending 10-15 minutes outside in the sun.

While sunscreen is always encouraged, it does restrict your body from absorbing enough vitamin D — even just allowing your hands to be exposed without sunscreen for 10 minutes daily is enough time to make the needed amount.

Between January and March, in Illinois and other areas across the country that get little sunlight in winter months, many people develop vitamin D deficiencies. Because there’s a connection between vitamin D and health outcomes, it’s important to know if you are at risk for developing or have a vitamin D deficiency. Your primary care doctor can order a test to check your levels and, if necessary, fill the void with supplements.

The pros and problems of probiotics

Probiotics have also become a hot topic among people interested in restoring the “good” bacteria in their gut and digestive system, and in turn, building a strong immune response. While foods like yogurt, cream cheese, kombucha or sauerkraut can provide natural forms of probiotics, the supplements in pill form pose a bigger challenge.

“Many drug store probiotics are not regulated,” says Gustashaw. “They don’t have the right bacteria, and we don’t know for sure what kind of microbiome people are deficient in. If you are taking an over-the-counter probiotic, it should be a well-vetted one, possibly suggested by your provider.”

Immune system health is more important than ever with new viruses like COVID-19 — illnesses that experts are still learning more about each day.

Generally, Gustashaw and Roehl recommend eating a diet rich in vegetables, nuts, seeds, fruit, whole grains and minimally processed meats and oils: high-nutrient value foods that can boost your immune system. And talk to your doctor and a registered dietitian nutritionist about which diet, supplements or lifestyle changes can help you best prevent future ailments.

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Food & Nutrition
Berry Crumble Recipe

Fresh berries and an easy crumble topping make this dessert a recipe you’ll return to over and over again. This delicious treat is a healthier alternative to traditional pie recipes.

The crumble can be made in a 9 x 9-inch baking dish or divided into four 6-ounce oven-safe bowls or ramekins for individual servings. 



  • 4 tablespoons sugar or stevia
  • 1 ½ tablespoons cornstarch
  • 1 ¼ cups fresh strawberries, chopped
  • 1 ¼ cups fresh raspberries, halved
  • 1 ¼ fresh blackberries, halved
  • 1 teaspoon lemon juice
  • Optional 
    • Add pinch of salt
    • Add fresh lemon zest

Mix ingredients together and spread evenly in baking dish(es). 


  • ½ cup whole wheat flour
  • 1 cup rolled oats
  • 1 cup sliced almonds
  • 1 teaspoon cinnamon
  • ¾ cup brown sugar (or alternative)
  • ½ cup melted butter

Combine ingredients until mixture is clumpy and then sprinkle on top of berry filling.

Baking Instructions:

Preheat oven to 375 degrees Fahrenheit. Place the baking dish(es) in the oven for 25-30 minutes, or until the crumble is golden brown. Let cool before serving.

Serve warm as is or with a dollop of whipped cream on top.

Food & Nutrition August 4, 2021
Cucumber Sesame Salad

Whether made with your homegrown produce or fresh vegetables from the store, our cucumber sesame salad is a fresh addition to your summer meals. This recipe makes the most of small amounts of honey, red pepper flakes, fish sauce and sesame oil to deliver a healthy and flavorful punch. Try it as a side dish or even for a main course.


  • 2 tablespoons extra-virgin olive oil
  • 2 garlic cloves, minced
  • 1/2 teaspoon crushed red pepper flakes 
  • 1 pound cucumbers (6 small)
  • 1 large bell pepper
  • 2 tablespoons unseasoned rice vinegar
  • 2 tablespoons fresh mint leaves, chopped, plus more for garnish
  • 1 teaspoon honey
  • 1 dash fish sauce (optional)
  • 1 dash sesame oil (optional)
  • 1 teaspoon toasted sesame seeds


  1. Heat oil in a small skillet over medium-low heat. Once hot, add garlic and chili flakes; cook 3 to 5 minutes, until garlic is golden and aromatic. Pour into a small bowl. Let cool completely.
  2. Meanwhile, chop cucumbers and bell peppers into thin slices. Place in a bowl.
  3. Mix vinegar, mint, honey, fish sauce and sesame oil in with garlic and chili flakes. Pour over cucumber and bell peppers. Sprinkle sesame seeds on top. Toss to combine.
  4. Garnish with additional fresh mint and sesame seeds, if desired.
  5. Serve immediately.

Nutrition Information

Makes 6 servings

Amount Per Serving

Calories: 60
Carbohydrates: 4g
Fat: 5g
Protein: 1g
Sodium: 26mg

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Food & Nutrition
Watermelon Feta Salad

Watermelon is already a standard of many summer barbecues, so give it a savory twist by turning it into a salad with blueberries and feta cheese. And with only a handful of healthy ingredients, try it the next time you need an easy side dish for an impromptu gathering.


  • 8 cups diced watermelon
  • 1 pint (2 cups) fresh blueberries
  • 1/4 cup fresh mint leaves, roughly chopped
  • 8 oz (1 cup) feta cheese — can use less
  • 4 tablespoons olive oil
  • 2 tablespoons balsamic vinegar
  • Salt and pepper, to taste
  • Optional additions: 1/4 cup red onion, 1/2 cup cucumber


  1. Add the diced watermelon, blueberries, mint and feta cheese to the bowl.
  2. Whisk together olive oil and balsamic vinegar.
  3. Pour over the fruit, mint and feta mixture.
  4. Gently mix to combine. Serve immediately.

Nutrition Information

Makes 8 servings

Amount Per Serving
Calories: 180
Carbohydrates: 18g
Fat: 4g
Protein: 4g
Sodium: 213 mg


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