The immune system includes complex processes, chemicals, and cells that defend the body against foreign invaders like viruses, bacteria, and other pathogens. When left unchecked, these invaders may lead to severe health complications. The immune system needs adequate nutrition to function efficiently and prevent infections or diseases. One could take supplements to build their immunity. However, healthy foods like the ones listed below may also help boost the immune system and keep illnesses at bay. Oranges Several people turn to foods rich in vitamin C to fight the symptoms of a cold. Oranges are a healthy source of vitamin C which helps improve the production of white blood cells. So eating this citrus fruit will help build the immune system and ward off or prevent potential health issues. Other healthy citrus fruits rich in vitamin C include clementines, grapefruit, limes, lemons, and tangerines. Broccoli The vegetable is flush with nutrients that can benefit one’s immune system. Broccoli is abundant in vitamin C, which boosts white blood cell production. The vegetable is also rich in vitamin K1, a vitamin necessary for blood clotting. Furthermore, it contains iron, an essential mineral for transporting oxygen across the red blood cells. Broccoli is also high in proteins, which are the building blocks of the human body.