NUTRITION AND IMMUNITY

The human immune system is a highly efficient and complex system that defends the body against foreign infectious agents such as bacteria, viruses, and parasites. Physical barriers form the body's first line of defense, including the skin and mucous membranes in the airways and digestive tract. Innate ("non-specific") and adaptive ("specific" or "acquired") mechanisms together form the actual immune system. Unlike other organs, such as the liver or fat, the immune system extends throughout the body and comprises a network of highly specialized immune cells and small molecules.