As flu season heightens, registered dietitians advise prioritizing a balanced diet of nutrient-dense foods to support the immune system. The immune system is directly connected to the gut, meaning that consuming the right nutrients can positively affect both. Erin Palinski-Wade, a New Jersey-based registered dietitian, told Fox News Digital that a lack of fiber, fermented foods, or other key nutrients can create an imbalance in the gut environment, which in turn impacts immune function.
The Centers for Disease Control and Prevention estimated that there were 51 million flu-related illnesses during the 2024-25 flu season. To help protect against such illnesses, Palinski-Wade recommends eating a variety of colorful produce. She noted that bright-colored items like bell peppers, kiwis, citrus fruits, and broccoli are excellent sources of vitamin C and a wide range of other nutrients.
Beyond fruits and vegetables, Palinski-Wade highlights the benefits of fermented foods such as yogurt, kefir, and sauerkraut for supporting the gut microbiome. Fiber also plays a significant role in gut health and immune support. She suggests beans, nuts, and seeds as effective options for increasing fiber intake. However, a report published in September by the American College of Cardiology found that only 6% of American adults consume enough fiber daily.
Protein and zinc are also essential for building immune cells, according to Palinski-Wade. She lists lean meats, shellfish, eggs, pumpkin seeds, and chickpeas as good sources of these nutrients. Lauren Manaker, a South Carolina-based registered dietitian, adds dairy milk to the list of immune-supporting beverages due to its vitamins and hydrating properties. Manaker told Fox News Digital that essential micronutrients in milk, including vitamin A, vitamin D, zinc, and selenium, support a healthy immune system.
A common misconception is that milk increases mucus and phlegm production. The Mayo Clinic states there is little scientific evidence to support this theory. Palinski-Wade explains that mixing milk products with saliva can create a sensation of a thicker coating in the throat, making it feel like there is more phlegm, even though production is not actually increased. For those who are lactose intolerant, Manaker notes that lactose-free milk offers the same key nutrients as regular dairy milk without the lactose.
Hydration is another critical component of immune support. Palinski-Wade explains that keeping airways moist serves as part of the body's first line of defense against colds and flu. She suggests sipping on water, broth, green tea, and ginger tea. Manaker adds that getting adequate sleep, managing stress, and staying physically active are also important for maintaining immune health.
Regarding supplements, Manaker says they can be helpful for individuals who struggle to meet nutrient needs through food alone. However, she advises consulting a health-care provider for guidance on dosages, noting that more is not always better.