The immune system is the body’s defense against germs, viruses and other invaders. The thymus gland, spleen, tonsils, adenoids and lymph nodes, along with a variety of white blood cells, all protect the body.
Common immune-system concerns include viruses, bacte ria, fungus, cancer, fatigue, influenza, AIDS and stress. You can do a lot to keep your defenses strong and boost your immunity. The first step is making good dietary choices.
EXAMINING THE IMMUNE SYSTEM
Prevention is a fundamental principle of natural health. One of the best things you can do to prevent disease and disability is to support your immune system.
The immune system consists of various body organs and processes. Key structures include the thymus gland, spleen, tonsils, adenoids and lymph nodes. White blood cells also help defend the body
This system is unlike other body systems in that it is not a group of physical structures (like the heart and blood vessels of the circulatory system), but a system of complex interactions involving many different organs, structures and substances. Among these are white blood cells, bone marrow, the lymphatic vessels and organs, specialized cells found in various body tissues, and specialized substances called serum factors that are present in the blood. Ideally, all of these components work together to protect the body against infection and disease.
The thymus gland plays a vital role in defending your body. It produces a special kind of white blood cell called a T-lymphocyte. This unique cell plays a profound role in creating “cell based” immunity. Immunity on a cellular level protects against fungi, viruses, bacteria and yeast infections. Your body has approximately one trillion lymphocytes.
The immune system helps protect us from malignancies. Tumor cells are always present in our bodies in small numbers. A healthy immune system will recognize and destroy tumor cells. When a person develops cancer, the immune function has failed to provide the body with protection. For some reason, the body does not recognize malignant cells, and they are allowed to reproduce.
After puberty the thymus gland begins to shrink. Because the thymus is believed to be the source of hormones involved in the maturation of T-lymphocytes (discussed later), it is crucial that we supplement our diets with nutrients that nourish and build this gland. These include vitamin C with bioflavonoids, selenium, vitamin E, beta-carotene, zinc and alpha lipoic acid. Recent clinical data support the notion that many of us become zinc -deficient as we grow older. This may help explain why elderly people become so much more susceptible to disease. Herbs that support the thymus gland include astragalus, eehinacea and pau d’arco.
The lymphatic system, which includes the tonsils, adenoids and lymph nodes, is responsible for collecting lymph fluid and draining waste from the tissues. This fluid must be purified by white blood cells, which destroy infections, kill microorganisms and remove cellular waste. Our lymph nodes also help produce armies of antibodies, which are special cells designed to kill specific organisms. Herbs like ginseng, golden seal and echinacea help support and cleanse the lymphatic system. Regular exercise also promotes lymphatic system health.
The body’s defense mechanisms are complex. In some cases, a virus must penetrate several lines of defense in order to cause a problem. Our defenses include the skin, mucous layers covering infection—susceptible tissues, white blood cells (or leukocytes) and interferon. Leukocytes are divided into two classes called granulocytes and agranulocytes. These two classes are further divided into smaller groups.
Granulocytes are primarily phagocytic, which means they have the ability to ingest particulate substances, a process called phagocytosis. Granuloeytes include juvenile neutrophils, segmented neutrophils, basophils and eosinophils. Neutrophils neutralize bacteria and small particles by ingesting them. Basophils are believed to deliver anticoagulants to facilitate blood-clot absorption. Eosinophils increase in numbers with asthma and during certain infections.
The agranulocytes include monoeytes and large and small lymphocytes. Monocytes can ingest large particles such as foreign proteins and peptides, while lymphocytes produce antibodies and are critical to cellular immunity.
Interferon is a protein that forms when cells are exposed to viruses. Uninfected cells will become immune to the virus when exposed to interferon. Interferon inhibits a virus’s ability to reproduce.
If the body’s ability to properly produce interferon or leukocytes is impaired, invading, disease-producing microorganisms may successfully challenge the health of the body. Weakening of the immune svstem results in increased susceptibility to virtually every type of illness. Some common signs of unpaired immune function include fatigue, listlessness, repeated infections, inflammation, allergic reactions, slow wound healing, chronic diarrhea and infections that represent an overgrowth of some normally present organism such is oral thrush or yeast infections.
TYPES OF IMMUNITY
The human immune system is functional at birth, but immunity really develops as the body matures and learns to defend itself against different foreign invaders called antigens The immune system has the ability to learn to identify and remember specific antigens that it has encountered. It does this through two basic means—cell-mediated immunity and humoral immunity.
In cell—mediated immunity, T—lymphocytes (or T—cells) identify and destroy cancerous cells, viruses and microorganisms like bacteria and fungi. These cells mature in the thymus gland— hence the “T” designation. Here they learn to recognize what is “self;” and therefore should be tolerated, and what is “non-self;” and therefore should be destroyed.
Humoral immunity involves the production of antibodies. These are not cells, but special proteins whose chemical structures form to match the surfaces of specific antigens. Antibodies concentrate in body fluids—tears, saliva, mucus, etc.—where they guard the entrances to the body. When they encounter their specific antigens, antibodies either damage the invasive cells or alert the leukocytes to attack.
Another group of white blood cells, the B-lymphocytes (manufactured by and matured in the bone marrow), produce the antibodies. When a B-lymphocyte meets a particular antigen, it engineers an antibody to match the antigen and stores a blueprint of the invader so it can initiate the production of antibodies in the case of any future exposure.
Key immune-boosting nutrients include vitamins A, C and B6, along with the minerals magnesium, selenium and zinc. The vast majority of people fail to get even Recommended Dietary Allowance levels of these nutrients from their diet, let alone optimal intakes. For this reason, supplementing with a high-quality comprehensive multivitamin is a proven way to boost your defenses. Vitamin C has antiviral properties and has proven successful against most viruses tested. The mineral zinc has been linked to the body’s ability to resist viruses.
Did You Know?
These suggestions can help you keep your immune sys tem in top form:
• Eat five servings of fruit and vegetables every day They contain many immune-boosting antioxidants and phytonutrients.
• Limit your intake of white sugar and refined-flour products.
• Eat less meat, eggs and dairy products, and be choosy about their source. Eat organic or free-range products whenever possible to avoid pesticides, antibiotic residues and other harmful additives.
• Drink plenty of pure water every day
• Take a good all-around multivitamin and 1,000—2,000 mg of vitamin C every day
• Keep fit by exercising regularly. While it’s true that too much exercise can weaken the immune system, most Americans don’t come close to overdoing it.