Boost Immunity Against Flu: Experts Say Eat The Rainbow

Flu season is ramping up, and experts warn that keeping your immune system strong starts with what you put on your plate. A diet packed with nutrient-dense foods is the foundation of a healthy defense line against illness. The gut and the immune system are linked directly; feed one, and you support the other.

"If we're not getting enough fiber, fermented foods or the right nutrients, we can get that imbalance in the gut environment, and that's going to impact the immune system," Erin Palinski-Wade told Fox News Digital from New Jersey. She is a registered dietitian who sees this connection clearly every day.

The numbers are stark for those ignoring prevention. The Centers for Disease Control and Prevention estimates there were 51 million flu-related illnesses during the 2024-25 season alone. That is too many cases to dismiss as just bad luck.

So, what should you actually eat? "Eat the rainbow, especially when it comes to produce," Palinski-Wade advised. Think bright colors like bell peppers, kiwis, citrus fruits, and broccoli. These are excellent sources of vitamin C plus a wide range of other nutrients your body needs right now.

Don't stop at fruit and vegetables. Fermented foods such as yogurt, kefir, and sauerkraut help support the gut microbiome, Palinski-Wade noted. Fiber is equally critical for gut health and immune function. Beans, nuts, and seeds are fantastic ways to boost your intake. But here is a hard reality check: only 6% of American adults consume enough fiber daily, according to a September report by the American College of Cardiology. Are you in that tiny group or not?

You also need protein and zinc. "These are really the building blocks our body needs to build the immune cells," Palinski-Wade said. Lean meats, shellfish, eggs, pumpkin seeds, and chickpeas work well for this purpose.

Lauren Manaker, a registered dietitian based in South Carolina, pointed out that dairy milk deserves a spot at your table too. It offers vitamins and hydrating benefits essential for immunity. "Several of the essential micronutrients found in milk, including vitamin A, vitamin D, zinc and selenium, support a healthy immune system," Manaker told Fox News Digital.

A lot of people avoid milk during sickness because they think it causes mucus. That is a common misconception. There is little scientific evidence to back that theory up. The Mayo Clinic explains that dairy might feel like it increases phlegm due to the sensation in your throat, not actual production. "When you take milk products, and you mix them with saliva, it can feel like a thicker coating in your throat," Palinski-Wade said. "It doesn't really mean you're producing more, but it can make you feel that way." If you are lactose intolerant, switch to lactose-free milk. It offers the same key nutrients as regular dairy without the sugar that upsets some stomachs.

Staying hydrated is just as important as eating well. "The hydration helps you feel your best," Palinski-Wade said. But there is more to it. Keeping airways moist is part of your body's first line of defense against catching a cold or the flu. Sip on water, broth, green tea, and ginger tea throughout the day.

Sleep, stress management, and physical activity round out the picture for a resilient immune system, according to Manaker. Supplements can be helpful if you struggle to get enough nutrients from food alone. However, be careful with dosages. "More is not always better," she warned. Always ask a healthcare provider for guidance before adding anything new to your routine.