You know it is going to be a rough few days the moment when the sore throat, runny nose, headache, cough, and body aches begin. Often, these ailments—aka, a common cold and the flu—are caused by the rhinovirus, respiratory syncytial virus, parainfluenza virus, and the influenza viruses. Contrary to popular belief, vegans can get sick, too, as vitamin and nutrient deficiencies can trigger a significant decrease in our immune system function, therefore allowing the invasion of one of these viruses into our bodies. The good news is that certain plant foods can help prevent—and even treat—the common cold and flu. Here are five foods I recommend to my sick patients. Of course, if you find that you develop a high fever, have trouble breathing, or have a sudden worsening in your symptoms, you should call your doctor immediately.

1 Fungi

Besides being delicious, nutritional yeast and mushrooms also help you when you are sick, as fungi break down dead organic material and provide medications such as penicillin. Nutritional yeast boosts the immune system but also suppresses the inflammatory response that might arise as the immune system raises its defenses. A spoonful of nutritional yeast a day reduces common cold recurrence by 25 percent, so go nooch! Furthermore, mushrooms are also beneficial by boosting natural killer-cell activity. Natural killer cells are a type of white blood cell that binds to virus-infected cells and then kills them (hence the name). Don’t forget you should eat cooked mushrooms—not raw—as they contain naturally occurring agaritine, a potentially toxic substance that is deactivated by cooking. 

2 Kiwifruit

When eaten by elderly people (typically those over 65), the consumption of kiwifruit can reduce the severity and length of a cold from one to five days. For preschool-aged children, kiwifruit decreases the risk of getting a cold or the flu by 50 percent. Therefore, adding sliced kiwifruit to your salad is not only sweet for your taste buds but also for your immune system.

3 Cruciferous vegetables

Arugula, bok choy, broccoli, Brussels sprouts, cabbage, collard greens, kale, kohlrabi, mustard, rutabaga, and turnips are just a few vegetables from the cruciferous family known for their anti-cancer properties. What many people don’t know is that these foods also support the immune system when isothiocyanates are released. Isothiocyanates are created when the vegetables are chewed or chopped up, which is one reason why having a green smoothie every day is recommended. These crunchy cruciferous vegetables also support the immune system’s interferon activity. Interferon is a protein released by the body’s cells when it has been invaded by a virus or other pathogen, altering neighboring cells to increase their defenses. Therefore, the interferon “interferes” with the virus’s ability to replicate.

4 Garlic

Garlic does more than keeping vampires away, as it enhances the immune system, too. Chopping garlic and letting it sit for 15 minutes prior to cooking and eating it is necessary because crushing the plant cells triggers the enzyme reaction that activates the healthy compounds. Garlic stimulates certain immune system cell types such as macrophages, lymphocytes, natural killer cells, dendritic cells, and eosinophils. Each has an important role in keeping us healthy: macrophages gobble up cellular debris and act as scavengers, clearing the body of waste and foreign substances, while lymphocytes and eosinophils are types of white blood cells that respond to different types of infection or inflammation (such as viral infections and allergic reactions); natural killer cells are a type of lymphocyte that are integral in fighting off viral infections; and dendritic cells are immune system messenger cells.

5 Berries

Berries such as Indian gooseberries, wild bilberries, strawberries, currants, and goji berries contain a high antioxidant content. Antioxidants protect our cells by neutralizing free radicals that cause damage through oxidative stress. Antioxidants found in elderberry juice can shorten the duration of the flu, while the resveratrol in grapes stops the flu virus from replicating. Adding berries to your oatmeal or a teaspoon of Indian gooseberry (also known as AMLA) powder to your smoothie in the morning is not only a great way start to your day but could also help prevent the next cold or flu virus from attacking you.

For more tips to fight the common cold and flu, read:
5 Effective Ways to Conquer Cold Season
5 Vegan Foods to Fight off the Winter Flu
5 Vegan Foods for a Healthy Immune System

Laurie Marbas, MD, MBA, is the medical director at Dr. Fuhrman’s Health Oasis in Boca Raton, FL.