The immune system is perhaps the body's sixth sense. It recognises viruses and bacteria the brain doesn't identify, and then converts that information into hormones that go to the brain to activate the immune process.

The immune system works in partnership with other protective body systems. For example, the skin forms a physical barrier against foreign materials, while the respiratory system utilises cilia, mucus and coughing to rid the body of inhaled microbes and pollutants. In addition, acid in the stomach and enzymes in the pancreas and intestines destroy many harmful micro-organisms.

If foreign materials overcome the body's other protective mechanisms, then the immune/defence system begins operating. This system is composed of lymph nodes, blood proteins (known as immunoglobulin) and specialised white blood cells such as lymphocytes, as well as the organs that produce these cells and the blood vessels that transport them.

Lymph nodes, or lymph glands as they are sometimes called, are usually small oval structures that are normally the size of small kidney beans. They are generally located in clusters near veins at strategic points along medium-sized lymph vessels at the knee, elbow, armpit, groin, neck, abdomen and chest.

The lymph nodes clean and filter blood, and serve as a gathering place for germ fighting cells during illness. The filtration process prevents bacteria, cancer cells and other infectious agents from entering the blood and circulating through the system. The lymph nodes are also centres for production and storage of some of the white blood cells, namely the lymphocytes and monocytes, which are important elements in the body's immune mechanism. During any kind of infection, the nodes become enlarged due to the multiplication of lymphocytes in the node.

All of the parts of the immune system are designed to reach rapidly to disease producing organisms and their toxins. If the disease gets past these defences, the body produces a generalised fever, localised inflammations and other reactions designed to conquer unwelcomed invaders.

Antibodies (immunoglobulin) are important for proper function of the immune system. These proteins distinguish between the body's own protein and foreign protein. When foreign protein is identified, antibodies can destroy it. It is estimated that there are 100 million different kinds of antibodies, each of which is custom-built.
The body constantly battles mutant cells. Some immunologists believe that there are always malignancies in the body and that they are usually recognised and destroyed by the immune system.

We live in a world of natural poisons and man-made pollutants. These environmental pollutants, along with improper diet and other harmful habits such as smoking and improper rest, can reduce the body's ability to protect itself from harmful bacteria, viruses, chemicals and other factors which can lead to disease.

Purdue University nutritionist Thomas Petro, Ph.D., wrote, "It's not that certain nutrients affect the immune system-it's that every nutrient affects the immune system." For that reason, a balanced diet is probably the most important consideration in maintaining a healthy immune system. In addition, when the body is deprived of some minerals, it is more likely to retain pollutants.

A great deal of focus has been directed at the antioxidant vitamins A, C and E because of their function in protecting the cells from damage caused by natural body processes, lifestyles, environmental and chemical pollutants. These vitamins, along with the trace mineral selenium, help prevent important molecules and structures within the cell from reacting with oxygen, which often injures - literally burns - the cell structure. This process is called oxidation.