With flu season underway, dietitians say one of the most overlooked tools for staying healthy is already sitting in the kitchen: a diet built around nutrient-dense, whole foods that support both digestion and immunity.
The Centers for Disease Control and Prevention estimated 51 million flu-related illnesses during the 2024-25 season. Health experts say individuals have real options for bolstering their own defenses beyond vaccination, starting with what they eat.
New Jersey-based registered dietitian Erin Palinski-Wade told Fox News Digital that the immune system is closely tied to gut health, and a poor diet can throw that relationship out of balance.
“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,” Palinski-Wade said.
Color, Fiber and Fermentation
Palinski-Wade recommends loading up on colorful produce. “Eat the rainbow, especially when it comes to produce,” she said, pointing to bell peppers, kiwis, citrus fruits and broccoli as strong sources of vitamin C and other nutrients.
Fermented foods such as yogurt, kefir and sauerkraut help maintain a healthy gut microbiome, she said. Fiber matters too — beans, nuts and seeds are good sources — yet a September report from the American College of Cardiology found only 6% of American adults get enough fiber daily.
Protein and zinc are also essential, according to Palinski-Wade, since “these are really the building blocks our body needs to build the immune cells.” She named lean meats, shellfish, eggs, pumpkin seeds and chickpeas as solid sources.
The Case for Dairy
South Carolina-based registered dietitian Lauren Manaker highlighted dairy milk as an immune-supporting beverage because of its vitamin and hydration benefits.
“Several of the essential micronutrients found in milk, including vitamin A, vitamin D, zinc and selenium, support a healthy immune system,” Manaker said.
Manaker and Palinski-Wade both pushed back on the common belief that milk worsens mucus production during a cold. The Mayo Clinic notes there’s little scientific evidence for that claim — the sensation people associate with increased phlegm is likely just the feel of milk mixing with saliva.
“It doesn’t really mean you’re producing more, but it can make you feel that way,” Palinski-Wade said. For those who are lactose intolerant, Manaker said lactose-free milk “offers the same key nutrients as regular dairy milk, just without the lactose.”
Hydration and Lifestyle Habits
Staying hydrated is another piece of the puzzle, Palinski-Wade said, since moist airways serve as the body’s first line of defense against cold and flu viruses. She suggested water, broth, green tea and ginger tea as good options.
Manaker added that adequate sleep, stress management and regular physical activity round out a strong immune-support strategy.
As for supplements, Manaker said they can help people who struggle to meet nutrient needs through food alone, but she urged consulting a health-care provider first. “More is not always better,” she said.
