Ten Foods to Boost Your Immune System

Jaclyn Tolentino, DO
December 24, 2018

From fighting off the common cold to preventing long term illness, a strong immune system is an integral part of of your health. That’s why these ten immune-boosting foods should be on your plate.

Your immune system is a network of organs and cells throughout the body that work together to protect you against foreign invaders. Your lymph nodes, spleen, bone marrow, white blood cells, cytokines, thymus, and lymphocytes are all part of this defense network.

Having a strong immune system is important for fending off viruses, bacterial infections, and chronic disease. But things like chronic stress , a poor diet , and excessive alcohol consumption can all impair your immune function. Since your immune system can be altered by environmental and lifestyle factors, it’s possible to bolster your defenses using things like nutrition. These are some of the best immune boosting foods.

Green and Black Tea

The immune-boosting effects of green and black tea are largely attributed to the presence of catechins, which boast impressive health and antioxidant benefits thanks to their polyphenol and flavanol content. Studies suggest epigallocatechin gallate (EGCG), a compound found in tea, offers potentially protective effects against everything from certain bacterias to digestive and breast cancers. As a hydrating, low-calorie beverage, green and black tea can be enjoyed daily, but be mindful of caffeine content—one cup of black tea can contain up to 47 mg of caffeine, so limit consumption if you are particularly sensitive or suffer from a health condition that requires you to limit caffeine intake.


Papaya is a tropical fruit with bright yellow or orange flesh, that rich and gently sweet flavor and buttery-soft texture. Papaya is high in fiber in a variety of antioxidants including beta carotene, as well as vitamin K, potassium, and choline. While its high fiber and water content alone are great for digestion, papaya also contains an enzyme called papain, a digestive enzyme important in breaking down amino acids.


Creamy, fiber-rich avocados also happen to be packed with an impressive amount of glutathione , a compound with antioxidant properties that’s thought to stimulate the immune system. Glutathione provides cells with powerful protection against oxidative damage, and half of an avocado offers about 19 mg, making it an incredibly potent source of this molecular powerhouse. In addition to antioxidants, avocados are also an excellent source of potassium, lutein, and vitamins E, C, K, and B-6.


Recognizable for its striking yellow-orange color, curcumin is a polyphenol extracted from the turmeric root. Research has shown it can have anti-inflammatory effects by inducing the expression and production of interleukin-10, an anti-inflammatory and immunosuppressive cytokine. Although turmeric has a low bioavailability on its own—meaning it has a limited ability to be absorbed and utilized in the body—when combined with an active compound found in black pepper, its bioavailability is substantially increased.

Cruciferous Vegetables

Cruciferous veggies, including broccoli, cauliflower, bok choy, cabbage and Brussels sprouts may provide an important boost to our immune system as we age. Thanks to a chemical called sulforaphane, diets high in cruciferous vegetables can activate certain antioxidant genes and enzymes in our immune cells, reinvigorating our body’s ability to fight free radicals and eliminate toxins. Cruciferous vegetables also play a role in helping our body to eradicate carcinogens, suggesting that they may also have cancer-fighting properties in addition to containing powerful antioxidants.

Leafy Greens

Dark, leafy greens are excellent sources of fiber, folate, iron, calcium, and vitamins C and K and they have also recently been shown to play a critical role in regulating the immune system by providing important chemical symbols that encourage immune cells in the gut to function properly. Arugula, spinach, and especially kale are great sources of these nutritious compounds.


Raw garlic has natural antimicrobial properties , meaning it can help play a role in fighting infection. That’s why the plant has a long history of medicinal usage and is a frequent ingredient in home remedies for cold and flu symptoms. Consumption of garlic has also been associated with blood pressure and cholesterol regulation, as well as protecting against some types of digestive cancers.


Mushrooms are high in things like antioxidants and phytonutrients, which means that many of them play a function in protecting the body against oxidative stress . While you may be more familiar with the culinary usage of certain mushrooms, like antioxidant packed Shiitakes, most medicinal mushrooms are intended to be consumed in dried powder form. You can add this powder to a smoothie or bone broth for a powerful immunity-charging beverage. Beneficial types include muscle-recharging Cordyceps, and cancer-fighting Turkey tail and Reishi.


Almonds are usually praised as a nutritionally satisfying snack that may also contribute to weight loss and maintenance but they may also have immune boosting properties thanks to their abundant vitamin E. Like glutathione, vitamin E is an antioxidant that works in the body by minimizing the damaging effect of free radicals. A one ounce serving of almonds provides 35% of your daily recommended vitamin E .


Thanks to an abundance of essential omega-3 fatty acids and B vitamins, salmon is an almost unbeatable protein source when it comes to health benefits. Omega-3 fatty acids are are an essential dietary fat that are associated with lowering blood pressure, inflammation , and cancer risk. Salmon’s high B vitamin and potassium content also provides benefits for cognitive function and stroke prevention, as well as reducing blood pressure.

Jaclyn Tolentino, DO

Dr. Jaclyn Tolentino is a board-certified Family Physician with a collaborative, holistic approach to practicing medicine. She specializes in hormone wellness, fertility optimization, and immune health. She has received extensive training through the Institute of Functional Medicine, and has additional experience in integrative oncology.

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