Citrus fruits: they are powerhouse nutrient. Recent studies have found that, intake of Vitamin C at the initial stage of illness may reduce the duration of cold by about a day. Just about (1,000 to 8,000 milligrams) of the vitamin C in butternut squash, papaya, broccoli, sweet potatoes, and tomatoes will do the trick. Grape fruit containing limonoids, a natural compound, lowering cholesterol, it is good for cold and flu.
On the other hand, there are chances of getting digestive problems, when this symptom is found it is good to cut back.

Mushrooms: there are different types of mushrooms that contain some form of immune-boosting antioxidants that helps control flu. Again, it comes along with potassium, B vitamins, and fiber.

Bananas: Whether they are sliced, pulverized or had whole, bananas are easy on the stomach and kids who very often be ill with the flu together with nausea or diarrhea can take up this, along with some mild toast or applesauce. It is one of the fruits had to see whether the kids are ready for solids.

Greens like arugula and kale works well on relieving chest congestion, sniffles and coughs.

Sweet potatoes and carrots- Rich in beta-carotene, intake of this will result in a conversion process i.e. the organic compound of it gets converted into vitamin A, which is indispensable for sustaining a strong immune system.

Cranberries – compared to other common fruits and veggies, cranberries have more antioxidants. Best part about the berry is that, one serving has just about more than five times the amount in broccoli. Boosting up good bacteria levels in the gut and defending it from foodborne illnesses; they are a natural probiotic that helps combat cold and flu.