The immune system is the body's defence against harmful agents. These agents can be outside enemies, such as bacteria, viruses, fungi and parasites; or chemicals; or inside enemies such as defective cells. The first line of defence is the "walls" between the outside and the body; these consist of the skin and the linings of the lungs and digestive tract. If these are strong and efficient, they prevent many harmful materials getting in.

Mucosal Membranes

The mucosal membranes of the lungs and intestines are designed to admit nutrients, but exclude harmful materials. The skin is normally impervious to most harmful substances. As the mucosal membranes are not complete barriers, a second line of defence is obviously necessary. This is the white cells of the immune system.

Immune Army

A mobile and flexible army is needed. The types of immune cells in the army are:

B‑Lymphocytes

These are so called because they are produced in the bone marrow. They produce antibodies to invading organisms. These prevent viruses from entering body cells and reproducing, and prevent bacteria from producing toxins. Their main function, however, is to tell more powerful immune cells to come and destroy invaders.

T Cells

Produced in the thymus. Helper T cells help other immune cells to function, suppressor T cells control others and turn them off when the battle is won, and cytotoxic (killer) T cells attack foreign, cancer and virus‑infected cells.

Others

Macrophages are large cells that engulf invaders identified by B and T cells. Monocytes are macrophages in the bloodstream. Mast cells break down antibody/antigen complexes, causing inflammation and allergic reactions.

Immune battle area

The main battle takes place in the spleen, lymph nodes, tonsils and appendix. The lymph vessels transport invaders to these positions for destruction.

Improving the immune system

a) Nutrition

Malnutrition weakens immune function, but some  specific nutrients are important:

¨      Vitamin A and beta‑carotene; have powerful anti‑oxidant effects, and also help the integrity of internal surfaces, excluding harmful substances.

¨      Vitamin C; now well known to be of importance for immunity, and also has direct antiviral and antibacterial effects. Suggested dose 1000mg 2/day, rising to 1000mg/hour during infections.

¨      Zinc; important particularly for production of T cells, but also needed for other white blood cells.

¨      Vitamin B6; for antibody production.

¨      Antioxidants; vitamin E, selenium and manganese all improve immunity.

¨      Newly Recognised: L‑glutamine is now recognised as the main fuel for the immune system, and for repair of the walls of the digestive tract. It can help in building up immunity, and particularly during an infection. Minimum dose during an infection; 2x5g teaspoons/day, away from food.

b) Herbal

¨      Cats Claw: more powerful anti‑infective agent than any other herb, particularly against viruses. Dose: 6x1000mg/day immediately at the start of infection; often works in 48 hours.

¨      Echinacea; immune booster. Enhances macrophage and T cell production.

Note

¨      Sugar; excess sugar intake is known to reduce white blood cell activity for many hours.

¨      Strenuous exercise; reduces white cell activity for several hours. L‑glutamine, taken immediately after exercise, may prevent this.

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