Think of the time a tiny splinter embedded itself in your thumb. By bedtime, the spot rose and reddened; by morning, white blood cells had launched their campaign, building a hot, throbbing fortification. By day's end, the bit of wood was propelled to the surface and ejected by the immune system warriors. Once again, a foreign assailant was summarily ousted.

The Protective Force
The immune system is a dazzlingly complex mechanism charged with guarding against infection, colds, flu and cancer. Laced with networks of couriers and transmitters, backed up by intricate fail safe devices and reinforced by memory units, immunity constantly adapts to highly specific and evolving needs.

"Supporting the immune system is critical to good health. Conversely, good health is critical to supporting the immune system." So write naturopathic doctors Michael T. Murray and Joseph E. Pizzorno in their Encyclopedia of Natural Medicine (Prima).

Maintaining the immune system requires a comprehensive program of wholesome diet, resilient attitude, fitness enhancing activity and nutrients keyed to the clear and specific needs of this energetic machine.

The all-star lineup for immune sustenance: a high-potency multiple vitamin/mineral formula, vitamins C and A, bioflavonoids, isoflavones, zinc and selenium, antioxidants like ActiVin (grape seed extract) and pycnogenol (French maritime pine bark), as well as the botanicals echinacea and astragalus.

But optimal partnering with your immune system also benefits from understanding its workings.

The Battlefronts
The immune system wages war on the organ, tissue and cellular fronts. It encompasses the lymphatic vessels and organs (lymph nodes, thymus, spleen and tonsils), white blood cells, specialized cells in particular tissues and customized chemicals.

Lymph, a milky fluid consisting of water protein and immune cells, is the essence of the immune system. Powered by muscle movement (an important reason why exercise boosts immunity), the lymphatic system collects and transports lymph to the lymph nodes. These nodes contain certain immune cells and filter out invading antigens, as well as produce antibodies, before siphoning the lymph out into the bloodstream.

If you've ever had "swollen glands," that means your lymph nodes have been in overdrive.

Macrophages are the immune cells that filter lymph, consuming bacteria and cellular debris while protecting the lymph system from invasion and damage.

Gland Tidings
Two organs dominate immune function: n The thymus. The most influential, critical gland of the immune system, located just below the thyroid gland and above the heart; produces T lymphocytes, white blood cells responsible for cell-mediated immunity not controlled by antibodies. This immune response is tailored to specific antigens and is vital to resisting infection from mold-like bacteria including yeast, fungi, parasites and such viruses as Epstein-Barr, herpes simplex and hepatitis. It also protects against cancer, allergies and autoimmune disorders like rheumatoid arthritis. n The spleen. The largest mass (about seven ounces) of lymphatic tissue in the body, located in the upper left abdomen behind the lower ribs; it produces white blood cells, which engulf and destroy bacteria and cellular debris; recycles material from worn out red blood cells and platelets; produces immune system enhancing compounds, including the proteins tufsin and splenopentin, and spleen extracts.

The White Blood Cell Album
Although white blood cells (WBCs) are uniformly accountable for protecting the body against bacteria, viruses, fungi and parasites, the different types of WBCs vary considerably in form and function. n Neutrophils phagocytize, that is, eat, viruses, bacteria and old or dead cells. They don't need any biochemical messengers for activation and their effectiveness is wide-ranging.

n Monocytes collect cellular trash after infections and can trigger immune responses; eosinophils can eliminate foreign particles and, with basophils, are involved in immune response.

n Lymphocytes include varieties of T cells, which work with other white blood cells or attack and destroy foreign tissue, cancer cells or virus-infected cells; B cells that produce antibodies that bind to bacteria, viruses or tumors; and natural killer cells (NKCs) that destroy cancerous or virally-infected cells.

(Based on information in the Encyclopedia of Natural Medicine; The Road to Immunity: How to Survive and Thrive in a Toxic World (Pocket Books) by Kenneth Bock, MD, and Nellie Sabin; and the Johns Hopkins Family Health Book (Harper Resource).

Keep the System Sound
Your immunity mechanism calls for special care and support. The dilemma: How to develop a balanced system of complementary and alternative therapies to build and sustain powerhouse immunity? "There is no question that, in terms of immune system response, certain supplements can reduce infections, asthma, autoimmune disease and risk factors for cancer," says Samuel D. Benjamin, MD, former project director of the Arizona Center for Health and Medicine and an ardent advocate for complementary medicine.

"But you must always be sure to maintain the mind-body-spirit link," he told Energy Times. "For the mind, it could be exercise, yoga or meditation. Evidence shows improved immune system responses from these therapies. And in any case, you never read in the headlines that somebody has been admitted to the emergency room overdosing on meditation.

"Intentionality also is an important part of the mind link: believing you are going to fare well. For your spirit, you must ask yourself such questions as, Do I feel connected to others?

"For the body, a daily multivitamin and mineral supplement. Much depends on your community: I live on Long Island, where there is a high incidence of breast cancer, so I would recommend green tea and isoflavones from soy products for women."

Dr. Benjamin stresses moderation in the use of immune-intensifying supplements, among which he cites mixed carotenoids, zinc and vitamin E.

The Soy Solution
Scientists who took the cue from the apparent link between high-soy Asian diets and low cancer incidence have developed a compelling case for soy as an immune-supportive anticancer agent.

In a study conducted by the University of Southern California at Norris and published in the March 4, 1998 Journal of the National Cancer Institute, researchers reported that genistein, an active component of soy products, short-circuits the ability of tumor cells to elude destruction by the immune system due to an excess of defensive stress proteins.

Genistein seems to make cancer cells vulnerable to the immune response. Researchers at Wake Forest University told participants at the January 1999 meeting of the American Association for the Advancement of Science that dietary or supplemental soy fed to monkeys counteracted cell proliferation that is a cancer precursor.

That Championship C
Probably the most widely recognized immune accelerator is vitamin C, an honored warrior against scurvy and, in 1970, again celebrated by Linus Pauling for its preventive powers over the common cold.

Immune cells are known to accumulate and retain high levels of vitamin C. Researchers at Memorial Sloan-Kettering Cancer Center in New York now understand how that happens: Proteins called growth factors (which control growth and production of immune cells) also increase those cells' ability to take up vitamin C.

These researchers, reporting in the April 1998 issue of the journal Blood, explain that the additional glucose that the growth factors pump into immune cells (for enhanced energy), plus extra vitamin C, intensify immune response.

And folks with higher levels of vitamin C in their blood serum experience less cell damage from free radicals that leads to cancer, heart and pulmonary disease and other chronic conditions.

Scientists at the University of Buffalo (addressing the June 13, 1997 meeting of the Society for Epidemiologic Research) deduced from studying population groups that high levels of vitamin C are associated with low oxidative stress and lower risk of cell damage.

From A to Zinc
n Kids with neuroblastoma, a malignant tumor of embryonic nerve cells and the third most common form of childhood cancer, experienced significantly improved survival rates when their therapy included high doses of retinoic acid, a derivative of vitamin A, according to researchers at the University of California, San Francisco, and Childrens Hospital Los Angeles, who reported to the American Society for Clinical Oncology on May 18, 1998.

n Colostrum, the pre-milk liquid produced by mammals during the first 24 to 48 hours after birth, took the spotlight recently as a supplement imbued with multiple immune factors and natural antibiotics that augment body's immune response. A 1992 study showed that bovine colostrum might be able to reduce and prevente infections in immune deficient folks, especially those with AIDS.

n University of Pittsburgh Cancer Institute researchers found for the first time (on laboratory animals) that vitamin D appreciably inhibits widespread prostate cancer by binding to cancer cells and triggering cell death or their transformation to benign cells.

n Vitamin E exerts formidable immune-enhancing influence on both antibody and cell-mediated immunity. One fundamental study in the Journal of the American Medical Association (245, 1981: 53-58) established conclusively that vitamin E deficiency results in significant impairment of immune function. Later studies demonstrated that it reduces prostate cancer by up to one-third.

n Coenzyme A, described as a metabolic enzyme, takes part in starting numerous body processes that provide energy for the immune system. If you ever run short of this enzyme, fat processing within your body would grind to a halt.

n Researchers looking at a substance with the tongue twisting name 3-acetyl-7-oxo-Dehydroepiandro-sterone, believe it aids immunity by quelling stress hormones.

n Mushrooms contain natural substances called polysaccharides, believed to enhance immunity. In particular, maitake mushroom, which conveys the immune booster beta-D-glucans, is reputed to help fight infections and drop blood pressure.

n Men and women taking selenium supplements for 10 years had 41% less total cancer than those taking a dummy, according to a January 1997 study by Cornell University and the University of Arizona. Other studies have shown it to reduce the risk for colon cancer by about 60%. n Zinc may provide immediate protection against the all too common cold. Scientists at the University of Florida were the first to apply genetic fingerprinting methods like those used in criminal and paternity investigations to understand how nutrients directly affect human immune cells.

The study, in the April 1998 Journal of Nutrition, demonstrates that zinc signals cells to make the protein metallothionein, which protects against infections, toxins and other stressors.

Phytochemicals a la Carte
Researchers extol the powers of phytochemicals in fruits and vegetables available in dietary or supplement form as immune-igniting antioxidants. These compounds neutralize free radicals that oxidize cellular membranes, rendering them vulnerable to cancer.The Strang Cancer Prevention Center, an affiliate of New York Presbyterian Hospital, offers a menu of the top antioxidant phytochemicals. The center's director, Mitchell L. Gaynor, MD, is coauthor (with Jerry Hickey, RPh) of Dr. Gaynor's Cancer Prevention Program (Kensington): n Carotenoids, including beta-carotene from veggies and lycopene (the substance that lends the tomato is ruddy complexion), fight free radicals.

n Isoflavones from soy, fight angiogenesis, the process by which new blood vessels form to supply nutrients to cancerous growths. n Sulforaphane in broccoli, kale and cabbage activates anticancer enzymes.

n Omega-3 fatty acids in cold water fish block the synthesis of prostaglandins, natural compounds in the body that promote tumor growth.

n Ginger contains antioxidant compounds, each more potent than vitamin E. Recent studies on mice show ginger can prevent skin tumors. n Rosemary contains carnosol which deactivates carcinogens and helps limit the effects of prostaglandins.

Sometimes the world can look like a dangerous place, especially when you're sick and tired much of the time. But in the search for immunity, menus of health help like this ensure that no matter what your immunity needs, a boost can be yours with the proper nutrient selection.