Immunity is important all year, every year, but it seems to have become an even hotter health topic than ever over the last few years. And it’s always of particular interest when cold and flu season rolls around (and lasts through the winter—and sometimes even early spring). Fortunately, it’s possible to protect yourself from sniffles and sick days by maintaining a healthy immune system on your own through everyday habits. One of the best lifelong ways to support your immunity is through nutrition and smart eating habits. Noshing on immune-boosting foods (and sipping on certain drinks) isn’t just effective, but easier and more delicious than you think.
Why Nutrition Matters for Immunity
If you’re on a mission to optimize immune function, your diet is a great place to start. Nutrition is a major factor affecting the immune system and, ultimately, how well the body is able to protect itself against harmful germs. Immune cells require certain nutrients to function properly, explains Gary E. Deng, MD, PhD, integrative medicine specialist at Memorial Sloan Kettering Cancer Center. These nutrients may work by triggering critical cellular reactions, providing energy for immune cells or fighting harmful molecules—just to name a few mechanisms, according to a 2019 article in the journal Nutrients.
Eat more plants, probiotics, and protein.
But what does eating for immunity look like, exactly? Luckily, according to the Academy of Nutrition and Dietetics, the best eating plan for a robust immune system aligns extremely well with familiar nutrition advice, and should focus especially on plenty of whole plants, most notably fruits and vegetables. Such plant foods offer fiber, vitamins, minerals, and antioxidants, which are all essential for fueling your immune cells. An immunity-boosting diet also calls for foods with probiotics (those “good” bacteria for a healthy gut microbiome) and lean protein, which both animal and plant sources can provide.
Eat less processed, packaged, and ultra-refined foods.
Immune system nutrition does involve eating less of certain foods, too. These less-advantageous eats generally include ultra-processed and refined foods, which are often stripped of immunity-supporting nutrients (e.g. natural fiber, phytochemicals, vitamins, and minerals). Not only do they fail to provide what’s needed, but they can also actively undermine the immune system when eaten in excess. They can cause oxidative stress and contribute to inflammation, prompting your body to use its supply of antioxidants to fight those processes, rather than being ready and able to fight the microscopic intruders that cause sickness, says registered dietitian Rhyan Geiger, RDN. Don’t worry, you can still enjoy ice cream and french fries! But your system will thank you if these treats become a lower priority in your everyday eating habits.
And, of course, what you eat and drink is only one part of enhancing immunity. Other important habits include managing stress, getting enough sleep (i.e., seven to eight hours for most adults), and staying physically active.
When it comes to daily meals and grocery shopping, here are the top immune-boosting ingredients to reach for.
The Best Foods for Immunity
In addition to supporting heart health and brain function, leafy greens like kale, spinach, Swiss chard, and arugula are some of the best foods to eat on repeat. “Leafy greens are rich in micronutrients, especially vitamin C and vitamin K, which [are essential for promoting] a healthy immune system” Geiger says. Other pro-immunity nutrients in leafy greens include beta-carotene and folate, or vitamin B9. To get your fill of leafy greens, aim for at least two cups per day, she says. And remember, you’re not limited to salads by any stretch: Try making a refreshing green smoothie or adding a handful of greens into soups, stews, omelets, pasta dishes, and grain bowls.
When it comes to gut health, probiotic foods such as tempeh, yogurt, kefir, kimchi, and sauerkraut steal the show. And since gut function is connected to immunity, these probiotic-rich choices are multifunctional superfoods. The “good” bacteria in probiotic foods strengthen the immune cells in the intestinal lining, Dr. Deng explains, adding that these microbes also metabolize foods to generate nutrients that otherwise wouldn’t be available to the body. This ensures your immune system gets the nutrients it needs to bring its A-game. For optimal immune-supporting benefits, Dr. Deng recommends adding probiotic foods to your diet two to three times a week. Start your morning with Greek yogurt with chopped nuts and berries; snack on naturally fermented pickles; or top your fish tacos with sauerkraut.
When it comes to immune-boosting foods, you can’t go wrong with berries such as strawberries, blueberries, and raspberries. According to Dr. Deng, berries are high in antioxidants, which help protect healthy cells from damaging molecules. Berries also offer vitamin C (especially strawberries), an essential immunity nutrient, and fiber, which support the “good” bacteria in the digestive tract, he adds. Aim for two half-cup servings of berries per week, which is easy to do with delicious eats like berry baked oatmeal and smoothie bowls. Or you can always munch on them by the handful straight from the carton in the fridge.
Although vitamins and antioxidants we get from plant foods are often associated with immune function, protein is just as crucial. “Protein [helps] the body repair tissues and muscle, build antibodies, and promote the synthesis of amino acids needed for immune function,” Geiger says. For the healthiest option, go for lean proteins, which are low in saturated fat. (This type of fat can raise your LDL or “bad” cholesterol when consumed in high amounts). Examples of lean protein sources include tofu, beans, lentils, skinless chicken or turkey, and white-fleshed fish like tilapia.
You can sip your way to better immunity, too. Delightfully refreshing and earthy, green tea is a must-have in your tea drawer. “Green tea has a variety of antioxidants, including [a] plant compound called epigallocatechin gallate,” Geiger explains. “This compound can help reduce inflammation in the body and improve function.” Enjoy green tea hot or cold, or add it to a smoothie for a tasty twist.