By Paula Havisto, PA-C
Ministry Medical Group

It’s easy to take your immune system for granted. It’s there for you day after day, but when it fails, you get sick.

Go online, and you will find numerous sites recommending certain foods or supplements to boost your immunity. Many of these offer health benefits, but don’t be lured too readily by the promises. As our front line of defense against infection and illness, the immune system is a complex network of cells, tissues and organs that work together.

What’s known as innate immunity includes the skin and the mucous membranes that line the nose, throat and gastrointestinal tract. They act as a wall to keep foreign invaders out. Also part of the innate immune system are cells that recognize broad, generalized dangers and respond quickly. There is also passive immunity such as the protection a baby gets from the mother’s milk.

And, finally, we have adaptive immunity that is constantly developing and changing throughout life, responding to various threats in the environment, including toxins, bacteria, viruses and fungi.

White blood cells known as leukocytes circulate throughout the body by way of lymphatic vessels and blood vessels. Two types include: phagocytes that chew up and destroy invading organisms and lymphocytes that remember organisms that caused trouble in the past and join with other cells to destroy them.

And there are two types of lymphocytes, B (as in bone-marrow-derived) cells and T (as in thymus-derived) cells. Actually, both types start in the bone marrow, but the T cells leave for the thymus gland, where they become mature cells.

When a foreign substance (antigen) enters the body, B cells produce specialized proteins (antibodies) that lock onto the antigen, identifying the threat and starting the attack. T cells, also known as killer cells, then gather other cells, including phagocytes, to destroy the invader.

Even after the battle has been won, the antibodies produced by B cells stay in the person’s body for long-term protection. If a similar antigen appears again, it will be recognized and disabled.
That’s the concept of immunity: if you have chicken pox once, you are protected from having it again by the antibodies lingering from the previous attack. Immunization also relies on this principle. A small, harmless quantity of the antigen is introduced through a vaccine, causing B cells to produce protective antibodies.

The system is effective, but several problems can occur.

Immunodeficiency occurs when part of the immune system is not working properly, whether because of a defect or damage caused by an infection or a medication. AIDS is acquired immunodeficiency syndrome, caused by HIV, a virus that destroys T helper cells. Medications such as chemotherapy drugs or those prescribed to prevent rejection of an organ transplant can also result in immunodeficiency.

Autoimmune disorders include lupus, rheumatoid arthritis and scleroderma. In each case, the immune system mistakenly identifies healthy organs or tissues as foreign invaders and launches an attack on them.

An allergy such as asthma or eczema is an over-reaction to one or more antigens in the environment.

The immune system protects against cancer as well as infectious diseases. But cancer can also occur in immune cells. Leukemia, for example, involves an abnormal overgrowth of leukocytes.

With all of these interactive cells and systems, it’s hard to imagine how any particular food or supplement could offer a certain boost. If you create more B cells, for example, is that positive or negative for overall immunity?

It’s easy to see, on the other hand, the benefit of healthy habits for keeping the individual components of immunity strong, active and working together harmoniously. Don’t smoke; eat a healthy diet; exercise regularly; and get adequate sleep.

Babies take a while to develop a strong immune system. And older adults tend to lose immunity. One reason for this loss of immunity is poor nutrition and deficiencies of certain essential vitamins and trace minerals.

Stress also has an effect on the immune system. While short-term stress may activate certain immune responses, studies have found that longer lasting stress can result in suppression of immunity.

Maintaining a strong immune system requires healthy emotional and mental–as well as physical–habits. Dealing promptly with chronic stress or depression might help keep the sniffles away this winter.

Paula Havisto, PA-C, is a Family Medicine Physician Assistant with Ministry Medical Group, Part of Ascension.