Vitamin D performs many functions in the body. We've known for a long time that vitamin D is essential for healthy bones and calcium absorption.
We're learning more about other roles of vitamin D in recent years. For instance, it may be integral for immune system health.
When the immune system is working well, the result is excellent health. But a malfunctioning immune system is an open door to infection and illness.
The workings of the immune system is complex, with many players. The following is a simplified version to make it easier to understand this important aspect of our bodies and its protectors.
The immune system is our defense against germs and microorganisms. It consists of specialized cells, organs, proteins and tissues. The cells are our white blood cells (leukocytes).
There are six types of white blood cells.
Neutrophils are our main protection against bacteria. They have the ability to chew up invaders by a process called phagocytosis. Immature neutrophils are called bands.
Eosinophils, basophils and monocytes are also involved in protecting us from infections and allergies.
Lymphocytes have the ability to recognize past invaders and destroy them when they are encountered later.
There are two types of lymphocytes which are B lymphocytes and T lymphocytes. Lymphocytes originate in bone marrow. They may stay in the marrow and become B cells, or they may head for the thymus and become T cells.
B lymphocytes look for targets and grab them. T cells then destroy the targets.
Antigens are invading substances. B lymphocytes produce antibodies which are proteins which target particular antigens. Antibodies remain, as protectors to the body.
If the same antigens return, antibodies are ready to dispatch them once again. But they need T cells to help destroy antigens, as well as to signal other cells such as neutrophils to assist by chewing them up. Antibodies render toxins harmless, and activate proteins that kill toxins.
The immune system protects us with this immune response -- when it's working properly. When it isn't, our immunity suffers.