When the body encounters germs, the immune system is its first line of defense. Specialized cells and organs help your body recognize and respond to foreign invaders. A strong immune system can protect people from illnesses and disorders such as common cold, flu, allergies, asthma or life-threatening conditions. Stress, lack of sleep, prolonged or overly intense exercise, and over-consumption of alcohol can weaken the immune system.

Certain nutritional supplements may help support the immune system such as vitamin C, colostrum, certain mushrooms, echinacea, oregano and olive leaf extract.