Vitamin D Council Glossary

Leukemia

Cancer of the blood or bone marrow that is characterized by abnormal proliferation of blood cells, usually leukocytes.

Leukocyte (Leukocytes)

White blood cell produced in the bone marrow that functions as part of the immune system, helping defend against infectious disease and foreign bodies.

Ligand (Ligands)

Molecule that binds specifically to a receptor site of another molecule.

Lipid (Lipids)

Fat-soluble, naturally-occurring molecule that is involved in energy storage and cell signalling and also serves as a structural component of the cell membrane. Examples of lipids are fatty-acids and sterol-containing metabolites such as cholesterol.

Lipoprotein (Lipoproteins)

A molecule composed of lipid (fat) molecules water-bound to proteins and that assists in the transport of fat to where it is needed in the body.

Low density lipoprotein (LDL,LDL cholesterol)

A molecule containing fat and protein that is commonly referred to as "bad cholesterol."

Lowest observed adverse effect level (LOAEL)

Lowest concentration or amount of a substance found by experiment or observation to cause harmful health effects in humans or animals.

Lumisterol

Naturally-occurring steroid compound that is part of the vitamin D family.

Lymph

Pale fluid that circulates (due to surrounding muscle activity) through the lymphatic system and contains lymphocytes and macrophages, the primary cells of the immune system.

Lymphatic system (Lymph system)

Major component of the body's immune system that interacts with every organ in the body, protecting and defending against infection, viruses, bacteria, fungi, and disease.

Lymphocyte (Lymphocytes)

Type of white blood cell in the adaptive immune system which plays an important role in the body's defenses. There are two categories of lymphocytes: the large, granular lymphocytes called natural killer cells (NK-cells) and the small lymphocytes called T-cells and B-cells.

Lymphoma

Cancer of the immune system cells known as lymphocytes.