Scientists and nutrition experts know that nutrient-rich foods filled with vitamins, minerals and antioxidants assist in keeping the immune system in tip-top shape. On the other hand, diets high in saturated fat and processed food may hamper the body's immune system.

Wendy Bazilian, a doctor of public health and registered dietitian, recommends loading up on a variety of colourful fruits and vegetables, not only during the flu season, but year-round. "Phytonutrients from plants are key to our immune system and keeping our energy revved," she says. "Intensely coloured fruits and vegetables tend to have the highest levels of antioxidants and nutrients to protect healthy cells and increase the cells that help fight infection and inflammation."

Here are Bazilian's top food picks for maintaining good health throughout the flu season.