Vitamin D Council Glossary

Macrophage (Macrophages)

Type of white blood cell that ingests foreign material. Macrophages are key players in the immune response to foreign invaders in that they help destroy bacteria, protozoa, and tumor cells. They also release substances that stimulate other cells of the immune system.

Magnesium

Mineral essential to all cells of all known living organisms. Every major biological process - including protein and nucleic acid synthesis, cellular energy production, and metabolism of vitamin D - requires magnesium.

Malignant (Malignancy)

Medical term used to describe a severe and progressively worsening disease, most often used as a description of cancer.

Matrix metallopeptidase 9 (MMP9)

Enzyme involved in normal physiological processes such as embryonic development, reproduction, and tissue remodeling, as well as in disease processes such as arthritis and metastasis.

Megalin

Endocytic receptor which plays a crucial role in renal vitamin D metabolism.

Melanin

Skin pigment produced in response to sun exposure by cells called melanocytes. Melanin is a natural sunscreen, protecting the skin from ultraviolet radiation-induced damage.

Melanocyte

Pigment- or melanin-producing cell in the skin, hair, and eye.

Melatonin

Hormone that communicates information about environmental lighting to various parts of the body, entraining biological rhythms. Melatonin has important effects on reproductive function in many animals and has been found to have antioxidant properties greater than those of glutathione.

Meta-analysis

Study design that is useful for providing insight into the overall effectiveness of interventions, the relative impact of independent variables, and the strength of relationship between variables.

Metabolic acidosis

Disruption of the body's acid/base (pH) balance that can either be a mild symptom or can indicate a more serious problem with a major organ such as the liver, kidney, or heart.

Metabolic syndrome (Syndrome X)

Cluster of conditions occurring together - such as increased blood pressure, elevated insulin levels, excess body fat around the waist, or abnormal cholesterol levels - that increases risk of heart disease, stroke, and diabetes.

Metabolism

Process of changing energy sources into energy that occurs in living cells, allowing the cells to grow and reproduce.

Metabolite

Any substance produced or used during metabolism.

Metastasis

Spreading of cancer cells from one organ or tissue to another, usually through the bloodstream or lymph system.

Microbe (Microorganism)

An organism that is too small to be seen with the naked eye such as bacteria, fungi, archaea, or protists.

Minimal Erythemal Dose (MED)

The amount of UV exposure required to cause slightly perceptible reddening of the skin of fair-skinned people and the level of exposure beyond that which production of vitamin D is already maximized.

Mitosis

The process by which the body grows and replaces cells.

MN1

Nuclear protein and calcitriol-induced VDR coactivator that also modulates osteoblast proliferation by slowing S-phase entry.

Monoamine neurotransmitters (Monoamine neurotransmitter)

Neurotransmitters and neuromodulators that contain one amino group that is connected to an aromatic ring by a two-carbon chain.

Morphogenesis

Processes involved in the structural formation of an organism, such as growth of tissues and organs during development.

Multiple Sclerosis (MS)

A disease that affects the central nervous system, causing a variety of symptoms including vision problems, muscular weakness, depression, speech difficulties, severe fatigue, cognitive impairment, and pain.

Mycobacterium

Pathogens known to cause serious diseases in mammals.

Myelin

Part of both the central nervous system and peripheral nervous system that lines nerve fibers to protect and insulate neurons. Myelin aids in the quick and accurate transmission of the electrical current that carries data from one nerve cell to the next.

Myeloma

An accumulation of malfunctioning or "cancerous" plasma cells, such as those that reside in bone marrow.