Vitamin D Council Glossary

# A B C D E F G H I J–K L M N O P R S T U V
Macrophage
A 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
Magnesium is a mineral that is essential to all cells of all known living organisms. Every major biological process, including protein and nucleic acid synthesis and cellular energy production, requires adequate amounts. Inadequate blood magnesium levels are known to result in low blood calcium levels, resistance to parathyroid hormone, and resistance to some of the effects of vitamin D.
Malignant
Medical term used to describe a severe and progressively worsening disease, most often used as a description of cancer.
Matrix metallopeptidase 9 (MMP9)
MMP9 may play an essential role in local proteolysis of the extracellular matrix and in leukocyte migration. Could also play a role in bone osteoclastic resorption and may be involved in the severity of coronary atherosclerosis.
Megalin
Endocytic receptor which plays a crucial role in renal vitamin D metabolism.
Melanin
Skin pigment that acts as a sunscreen and protects the skin from ultraviolet radiation. Melanin is produced by cells, called melanocytes, in response to sun exposure.
Melanocyte
A pigment-producing cell in the skin, hair, and eye that determines their color. see melanin.
Melatonin
A structurally simple hormone that communicates information about environmental lighting to various parts of the body and has the ability to entrain biological rhythms. Melatonin has important effects on reproductive function in many animals.
Meta-analysis
Meta-analysis provides a systematic overview of quantitative research which has examined a particular question and is helpful in 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 be a mild symptom or can indicate a more serious problem with a major organ such as the liver, kidneys, or heart.
Metabolic syndrome
Metabolic syndrome is a cluster of conditions that occur together—such as increased blood pressure, elevated insulin levels, excess body fat around the waist, or abnormal cholesterol levels—increasing your 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.
There are two types of metabolites:
Primary metabolite: directly involved in normal growth, development, and reproduction.
Secondary metabolite: function is usually of an ecological nature, such as defense against predators, parasites, and diseases, interspecies competition, and facilitation of reproductive processes.
Metastasis
Spreading of cancer cells from one organ or tissue to another, usually through the bloodstream or lymph system.
Microbe
also, 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 UVR exposure required to cause perceptible, yet slight, 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
MN1 is a nuclear protein and calcitriol-induced VDR coactivator that also modulates osteoblast proliferation by slowing S-phase entry.
Monoamine neurotransmitters
Monoamine neurotransmitters are neurotransmitters and neuromodulators that contain one amino group that is connected to an aromatic ring by a two-carbon chain.
Morphogenesis
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 the CNS and PNS, myelin lines nerve fibers to protect and insulate neurons, aiding in the quick and accurate transmission of electrical current carrying data from one nerve cell to the next. When myelin becomes damaged, the process involves numerous health conditions, including multiple sclerosis.
Myeloma
An accumulation of malfunctioning or "cancerous" plasma cells, such as those that reside in bone marrow.

*These statements have not been evaluated by the Food and Drug Administration. These products are not intended to diagnose, treat, cure, or prevent any disease.