As cases of coronavirus continue to rise, taking daily precautions such as washing your hands, social distancing, exercising and getting enough sleep is key to lowering risk of infection.

But maintaining a healthy diet to help boost your immune system may also give you an edge. It's important to note that no research has been done on foods that help fight against COVID-19 specifically.

However, previous studies have found that eating certain foods can improve your health and strengthen your body's ability to fight other invasive viruses.

Here are nine expert-approved foods to stock up on during your next grocery store trip, along with creative ideas on how to add them to your diet:

1. Red bell peppers

Red bell peppers reign supreme when it comes to fruits and vegetables high in vitamin C. According to the U.S. Department of Agriculture, one cup of chopped red bell peppers contains about 211% of your daily value of vitamin C. That's about twice more than an orange (106%).

A 2017 study published in the National Institutes of Health found that vitamin C contributes to immune defense by supporting a variety of cell functions and can lower the risk of respiratory infections. It can also help the growth and repair of tissues in your body.

"Daily intake of vitamin C is essential for good health because our bodies don't produce it naturally," Dr. Seema Sarin, an internal medicine physician at EHE Health, tells CNBC Make It.

She suggests slicing one up and eating it raw with hummus as a crunchy snack or mixing some into your salad. If you prefer them cooked, throw a handful in a pan for a quick stir-fry.

2. Broccoli

Broccoli is also rich in vitamin C. Just half a cup contains 43% of your daily value of vitamin C, according to the NIH.

"Broccoli is packed with phytochemicals and antioxidants that support our immune system," says Sarin. It also contains vitamin E, an antioxidant that can help fight off bacteria and viruses.

According to the Dietary Guidelines for Americans, vitamin C is one nutrient Americans aren't getting enough of in their diet, so finding simple ways to add it in is crucial.

"To get the most out of this powerhouse vegetable, eat it raw or just slightly cooked," says Sarin. "I love sauteing broccoli with garlic and Parmesan, or stir-frying with bell peppers, ginger, garlic and mushrooms."

3. Chickpeas

Chickpeas contain a lot of protein, an essential nutrient made of amino acids that help grow and repair the body's tissues. It's also involved in synthesizing and maintaining enzymes to keep our systems functioning properly, according to the Academy of Nutrition and Dietetics.

"Chickpeas are also packed with zinc, which helps the immune system control and regulate immune responses," Emily Wunder, a dietitian and founder of the nutritious recipes site Healthier Taste, tells CNBC Make It.

Roasted chickpeas are great as a quick great snack or salad topper. Make sure they're completely dry before roasting. Then add a few tablespoons of oil (vegetable, canola or grapeseed oil all work well) and bake at 400 degrees Fahrenheit, stirring halfway through until they're crispy.

For a nice kick, Wunder suggests adding some salt and paprika. If you're using canned chickpeas, she says you'll want to rinse them thoroughly to cut down on sodium content.

4. Strawberries

Wunder enjoys half a cup of strawberries to get 50% of her vitamin C needs for the day.

"Vitamin C is great for strengthening your immune system," she says, because it can help protect cells from damage caused by free radicals that we're often exposed to in the environment.

Wunder recommends adding chopped strawberries to yogurt, oatmeal or on top of whole wheat toast with peanut butter. "Of course, they go well with smoothies, too," she says.

5. Garlic

"Not only is garlic full of flavor, but it's packed with health benefits such as lowering blood pressure and reducing risk of heart disease," according to Sarin. "Garlic's immunity-boosting abilities come from its heavy concentration of sulfur-containing compounds, which can help fight off some infections."

Garlic has been shown in the past to help ward off the common cold. In a 2001 study published in Advances in Therapy, participants who took garlic supplements were less likely to catch a cold. And those who did get infected recovered faster than participants in the placebo group.

It's an easy vegetable to work into your diet, says Sarin. You can add to it anything — from pasta sauce and salad dressings to soups and stir-fry dishes. She suggests aiming to consume two to three cloves per day.

6. Mushrooms

"While sun exposure is the best source of vitamin D, it can also be provided by some foods, including mushrooms," says Wunder.

A 2018 review of mushrooms as a vitamin D source found that the "sunshine vitamin" can help enhance the absorption of calcium, which is good for bone health, and may also protect against some cancers and respiratory diseases.

Mushrooms are great as a side dish or appetizer. Wunder recommends roasting them at about 350 degrees Fahrenheit, using one to two tablespoons of oil, minced garlic and a dash of salt and pepper. For something more flavorful, bake button mushrooms stuffed with cheese, onion and artichoke hearts.

7. Spinach

"Spinach is rich in vitamin C and full of antioxidants that help shield our immune cells from environmental damage," says Sarin. "Plus, it has beta carotene, which is the main dietary source of vitamin A — an essential component of proper immune function."

Like broccoli, it's best to consume spinach raw or slightly cooked. To incorporate more spinach into your diet, Sarin suggests blending it in a smoothie, cooking it with your morning eggs or, as an easy side dish, lightly sauteing with garlic.

8. Yogurt

"Yogurt is a great source of probiotics, which are good bacteria that can help promote a healthy gut and immune system," says Sarin. Recent studies have also found probiotics to be effective for fighting the common cold and influenza-like respiratory infections.

Sarin recommends choosing plain yogurt — rather than anything too flavored or sweetened — and topping it with fruit and honey. "Or, you can add it to your favorite post-workout smoothie," she says.

Those on a dairy-free diet can still benefit from almond-milk and coconut-milk yogurt options.

9. Sunflower seeds

"Sunflower seeds are high in vitamin E, which works as an antioxidant and helps boosts the immune system," says Wunder.

Small but mighty, just one ounce of dry-roasted sunflower seeds can give you 49% of your daily value of vitamin E, according to the NIH.

Line a baking pan with parchment paper and roast unshelled sunflower seeds at 300 degrees Fahrenheit until they're lightly browned. Then add the seeds to your salad or toss them with roasted vegetables. You can also use raw seeds in place of pine nuts for some homemade pesto.

Brittany Anas is a health and nutrition reporter. She has written for HealthDay, Women's Health and The Denver Post. Follow her on Twitter @BrittanyAnas.

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