The human body comes equipped with its own defense mechanism, the immune system, that can protect you from illness. But you have to treat it right for it to work optimally. That self-care starts with diet.

“Adequate nutrition is required for all cells to function properly, including our immune system cells,” says Kristine Dilley, a registered dietitian at the Ohio State University Wexner Medical Center in Columbus. “If the immune system is activated to respond to a pathogen (an organism that can cause disease), optimal nutrition is needed to provide the extra demand for energy and nutrients. Undernutrition or malnutrition can impair immune function if insufficient nutrients are present to help the immune system do its job.”

In discussions of using food and drink to boost immunity, smoothies are often recommended because they’re loaded with fruits and vegetables that are great sources of antioxidants. (Antioxidants are compounds that can support many aspects of health, including healthy immune system function.) But if you’re looking for a delicious, immune-system boosting drink that’s not a smoothie, check out the following 11 options:

If you want to boost immunity, sticking with the basics is a great place to start.

“Of all the fluids that support a healthy immune system, water is the most important and should be our primary beverage of choice,” says Siera Holley, a registered dietitian nutritionist at the Ohio State University Wexner Medical Center. “Water is essential for absorbing certain nutrients, such as vitamin C, transporting nutrients throughout the body, maintaining body temperature and eliminating toxins.”

Adequate hydration also helps the lymphatic system move immune-boosting white blood cells through the body.

“However, the majority of people worldwide are not even reaching the lower ranges for adequate hydration,” notes Jennifer Hanway, a board-certified holistic nutritionist, certified personal trainer and health coach based in Boston, New York and London.

To determine your individual water needs, Holley recommends dividing your body weight in pounds by two. The resulting number is the minimum amount of water in ounces to aim to drink each day.

For example, if you weigh 150 pounds, you should drink at least 75 ounces of water daily.

If you want to jazz up your water, Holley recommends selecting sparkling or seltzer waters with no added sugar.

“Or, try experimenting with infusing water for more flavor by adding different combinations of sliced fruits, vegetables and/or herbs,” she suggests.

Kailey Proctor, an oncology dietitian at City of Hope in Southern California, recommends drinking kefir, a creamy, yogurt-like beverage made from fermented cow or goat’s milk.

“Kefir is an excellent source of probiotics, like most fermented foods,” she says.

What distinguishes it is a specific type of bacteria called Lactobacillus kefiri, which has been shown to protect the body from infections, Proctor notes.

A 2021 study conducted at Stanford School of Medicine may explain why. The study found that a diet rich in fermented foods can enhance the diversity of microbes in the gut, which offers a boost to immune system function. In other words, a diverse microbiome is better able to fend off a variety of pathogens it may encounter.

In addition, the study noted that levels of 19 different inflammatory proteins in the blood also decreased among participants fed a diet high in fermented foods. One of those proteins, called interleukin 6 (IL-6), has been connected with several conditions, including rheumatoid arthritis, Type 2 diabetes and chronic stress, the study notes. Four types of immune cells were also found to be less active in the group that ate more fermented foods, suggesting improved immune system function related to increased intake of fermented foods.

Keeping your gut healthy is all part of boosting immunity, confirms Mary Mosquera Cochran, a registered dietitian with the Ohio State University Wexner Medical Center. The gut “is a site of major immune system activity,” she says, so drinking beverages that are rich in probiotics, such as kefir, can be beneficial.

But it’s not just the bacteria that makes kefir a good choice.

“An added benefit of drinking kefir over other fermented drinks, such as kombucha, is that kefir products are often fortified with vitamin D, which has been found to play an essential role in healthy immune system functioning,” Cochran says.

If you’re going to add kefir, Cochran recommends sticking with plain kefir for less added sugar or avoiding kefir products with more than 12 grams of added sugar per serving.

If you want to avoid dairy, why not reach for a refreshing glass of agua fresca?

“Popular in Mexico and Central America, agua fresca is a delicious blend of water, whole fruit and lime juice,” Cochran says.

Agua fresca is high in vitamin C, a key antioxidant that can support a healthy immune system.

Cochran offers the following simple recipe:

• Add 1 cup of fruit (pineapples, oranges and strawberries are all rich in vitamin C), the juice of half a lime and 1 cup of water to a standard blender.
• Blend on high, pour and enjoy.

If you’d like a little spritz of bubbles, you can also try using unsweetened sparkling water.

Zinc is another important mineral needed for healthy immune function, and chia seeds are an excellent source of the nutrient. In fact, just 2 tablespoons of chia seeds contain 12% of your daily value of zinc.

Although you can certainly add a handful of chia seeds to any smoothie for an instant boost of zinc, Cochran also recommends trying this delicious and refreshing non-smoothie drink:

• Combine 1 cup of water with 3 tablespoons of chia seeds in a tall glass, cover and let soak for 15 to 20 minutes in your fridge. The chia seeds will swell and create a gel-like substance.
• Thin the mixture with 1 cup of your favorite no-sugar-added juice. Cochran recommends 100% pomegranate or cherry juice, as “both are very rich in antioxidants for more immune system support.”
• Stir to combine.

Even when using no-sugar-added juices, watch your serving sizes, as juices are typically high in natural sugars and calories. For example, a cup of pomegranate juice contains more than 30 grams of sugar and nearly 140 calories. Adding water can help stretch the juice with fewer calories.

Kids are often given milk as their primary drink, and there’s a reason for that, Holley says. Fortified cow’s milk provides multiple nutrients that support the immune system, including:

• Vitamin D, which helps bones absorb calcium and can support mood. Studies have shown that vitamin D helps to decrease inflammation and modulate immune response. However, the majority of Americans do not consume adequate levels of vitamin D. According to the Dietary Guidelines for Americans 2020-2025, people ages 2 to 70 should aim to get 600 international units of vitamin D each day, while people ages 71 and over should get 800 international units of vitamin D. One cup of milk that’s been fortified with vitamin D contains 25% of the daily value for vitamin D.
• Protein, which is beneficial for muscle repair and recovery.
• Vitamin A, which supports the immune system, internal organs and the eyes.
• Zinc, which is especially helpful for wound healing.

Milk contains calories, fat and natural sugars from its lactose content, so be mindful of portion sizes if you’re trying to manage your weight. Holley recommends choosing fat-free skim or low-fat (1%) milk “to reap the benefits of milk without the higher saturated fat content.”

If you can’t tolerate or don’t like dairy milk, Holley suggests fortified plant-based options instead.

“Soy and almond beverages can also be good options for getting vitamin D through food,” she says. “The unsweetened or unflavored variety of these beverages would be recommended to eliminate the intake of any added sugar.”

She also recommends checking the label on both dairy and plant-based milks to be sure you know which nutrients have been added.

Cashews and hemp hearts, which are hulled hemp seeds that look a bit like wild rice, are both excellent sources of zinc.

You can buy pre-made versions of both hemp and cashew milk. Cochran recommends choosing an unsweetened variety because “eating a diet high in added sugars can increase inflammation and wear down your immune system over time.”

She also suggests making a “cool and creamy summer beverage” with this simple recipe:

• Measure 3 tablespoons of hemp hearts or ¼ cup cashews into a small bowl. Cover with hot water, and let soak for an hour. You can also cover with room temperature water and soak overnight until soft.
• Once the hemp hearts or cashews have softened, drain and discard the water.
• Add the seeds or nuts to a blender, and combine with 1 cup of water, ½ teaspoon of vanilla extract and ½ teaspoon of maple syrup if you want more sweetness.
• Blend on high.

“You can drink it straight from the blender or strain it through a fine mesh sieve for a smoother texture,” Cochran says.