Flu and cold season is nearly upon us, and according to the Center for Disease Control (CDC) that means that between 5 and 20% of the U.S. population will soon be suffering with some sort of sickness between flu season's peak months of December and February. But before you get sick, you can boost your virus-fighting abilities by fortifying your immune system. And the best way to do that, holistic health practitioner and registered nurse Lydia Romero Johnson says, is through a nutritional clean up. 

“A poor diet can significantly affect your ability to fight the infections that you’re more likely to pick up during the colder months of the year,” Romero Johnson says.

Related: 5 Ways to Bullet-Proof Your Immune System With a Plant-Based Meal Plan

When you eat crappy foods and skip the nutrient-rich staples your body needs to function, you run a higher risk of getting sick. So, before you resign yourself to sneezing and coughing your way to the end of the year, swap out any junk in your meal plan for these seven powerful foods that not only fight the flu, but are also guaranteed to support your immune system.

The Best Foods to Help Your Body Fight the Flu and Other Sickness

1. Garlic

Garlic is one of the best flu-fighting foods to eat because it contains the compound allicin.

“Allicin is your immune system-building, cough- and cold-fighting friend,” Romero Johnson says. “In order to activate allicin’s superpowers, you have to crush or chop it first. And if you eat garlic raw in smoothies, salads, or salsa, it really maximizes the antioxidant and anti-inflammatory benefits."

2. Nuts

Making nuts your go-to snack during the winter season is another way to boost your body’s immunity, according to Mariya Goslin, an SGX coach and nutrition consultant based in Buffalo, New York. 

Related: Why Eating Whole Grains Can Make You Feel Better Mentally and Physically

Not only are nuts such as walnuts, almonds, and pistachios naturally packed with bacteria-busting vitamin E, but they’re also whole foods. This means that they retain other beneficial phytochemicals that are often removed in processed foods. 

“This leads to decreased inflammation, but also lower blood glucose levels, more energy, and better mental clarity,” Goslin claims.

3. Sweet Potato 

“The benefits are abundant with sweet potatoes,” Romero Johnson says. “A delicious, nutrient-dense comfort food, the sweet potato is a powerhouse of vitamin A, which is a great support for the immune system in the winter months.”

Fueling up on vitamin A is also a way to keep mucous membranes and skin healthy, which is important considering the skin is a significant physical barrier against bacteria and viruses.

Related: Are Sweet Potatoes Really Healthy? Here's What You Need to Know.

4. Green Tea

Romero Johnson was diagnosed with lupus in her 20s, and now works with a lot of patients online to help them better manage the autoimmune disease as part of their daily lives. 

“Fall and winter become a whole season of tea drinking for me!" she says. "Drinking green tea is the best, as it’s not only good for our skin but it naturally reduces inflammation.” 

This is primarily due to the antioxidant quercetin, which works to hinder a lot of the flu-like symptoms found in lupus, such as joint pain, fever, and fatigue. 

5. Kefir

Though all probiotics are helpful in warding off flu, kefir’s power-trio of zinc, B6, and vitamin C makes it an impressive virus killer. A 2015 study in the journal Frontiers in Microbiology found that kefir possessed strong antimicrobial, anti-inflammatory, and antioxidant properties that could reduce flu symptoms and recovery time. So next time you're feeling sick, add a little kefir to your meal plan and rest easy knowing it's one of the best foods to fight the flu. 

Related: How Probiotics Can Enhance Your Training and Overall Performance

6. Eggs

Eggs, particularly the yolks, are packed with powerful flu-fighting nutrients, vitamin D being one of the most important. 

Though the sun is the best source of vitamin D, “in winter, when our skin is covered and more often indoors, vitamin D is particularly important as many of us can become deficient," Molly Lee, a board-certified holistic nutritionist and author of Energizing Nutrition, says. 

Science concurs. One study found that three-quarters of U.S. teens and adults are lacking in vitamin D, while another highlighted the high prevalence of vitamin D deficiency among elderly people as a worrying risk factor in their susceptibility to flu and other viruses. 

7. Mushrooms 

Mushrooms may not be the first thing you’d reach for when it comes to foods to fight the flu, but they’re a major source of immune-busting zinc. And according to Lee, they also contain vitamin D, which makes them a good choice for vegans who need to pump up their intake of the sunshine vitamin. 

That said, Lee warns that a person would need to consume a lot of mushrooms to avoid vitamin D deficiency, and might need to consider taking a supplement to fill in the gaps.