The Science of Nutrition - Chapter 12

Iron-Deficiency Anemia

*Stage three*; a form of anemia that results from severe iron deficiency.

Homocysteine

An amino acid that requires adequate levels of folate, vitamin B6, and vitamin B12 for its metabolism. High levels of _____ in the blood are associated with an increased risk for vascular diseases such as cardiovascular disease.

Ferroportin

An iron transporter that helps regulate intestinal iron absorption and the release of iron from the enterocyte into the general circulation.

Myoglobin

An iron-containing protein similar to hemoglobin except that it is found in the muscle cells.

Platelets

Cell fragments that assist in the formation of blood clots and help stop bleeding.

Antibodies

Circulating proteins produced by plasma cells to a particular antigen in response to a disease or vaccination or acquired passively.

Nonspecific Immune Function

Generalized body defense mechanisms that protect agaisnt the entry of foreign agents such as microorganisms and allergens; also called innate immunity.

Antiserum

Human or animal serum that contains antibodies to a particular antigen because of previous exposure to the disease or to a vaccine containing antigens from that infectious agent.

Heme Iron

Iron that is a part of hemoglobin and myoglobin; found only in animal-based foods such as meat, fish, and poultry.

Iron-Deficiency Erythropoiesis

The *second stage* of iron deficiency characterized by a decrease in the transport of iron in the blood.

Folate-Deficiency Erythropoiesis

The *third stage* of folate depletion in which body levels of folate are so low that the ability to make new red blood cells is impaired.

Plasma

The fluid portion of the blood; it is needed to maintain adequate blood volume so that the blood can flow easily throughout the body.

Non-Heme Iron

The form of iron that is not a part of hemoglobin or myoglobin; found in animal-based and plant-based foods.

Heme

The iron-containing molecule found in hemoglobin.

Neural Tube Defects

The most common malformations of the central nervous system that occur during fetal development. A folate deficiency can cause neural tube defects.

Coenzyme

The nonprotein component of enzymes; many ______ are B-vitamins.

Hemoglobin

The oxygen-carrying protein found in red blood cells; almost two-thirds of all the iron in the body is found in _____.

Specific Immune Function

The strongest defense against pathogens. Requires adaptation of white blood cells that recognize antigens and that multiply to protect against the pathogens carrying those antigens. Also called adaptive immunity or acquired immunity.

Transferrin

The transport protein for iron.

T Cells

White blood cells that are of several varieties, including cytotoxic and helper.

B Cells

White blood cells that can becoe either antibody-producing plasma cells or memory cells.

Plasma Cells

White blood cells that have differentiated from activated B cells and produce millions of antibodies to an antigen during an infection.

Memory Cells

White blood cells that recognize a particular antigen and circulate in the body, ready to respond if the antigen is encountered again. The purpose of vaccination is to create memory cells.

Leukocytes

White blood cells; they protect the body from infection and illness.

Metallothionein

A zinc-containing protein within the enterocyte; it assists in the regulation of zinc homeostasis.

Cytotoxic T Cells

Activated T cells that kill infected body cells.

Helper T Cells

Activated T cells that secrete chemicals needed to activate other immune cells.

Immunocompetence

Adequate ability to produce an effective immune response to an antigen.

Vaccination

Administering a small amount of antigen to elicit an immune response for the purpose of developing memory cells that will protect against the disease at a later time.

Atrophic Gastritis

A condition, frequently seen in individuals over the age of 50 years, in which stomach-acid secretion is low.

Hephaestin

A copper-containing protein that oxidizes Fe2+ to Fe3+ once iron is transported across the basolateral membrane by ferroportin.

Ceruloplasmin

A copper-containing protein that transports copper in the body. It also plays a role in oxidizing ferric to ferrous iron.

Autoimmune

A destructive immune response directed toward the individual's own tissues.

Macrocytic Anemia

A form of anemia manifested as the production of larger-than-normal red blood cells containing insufficient hemoglobin, which inhibits adequate transport of oxygen; also called megaloblastic anemia. _____ can be caused by a severe folate deficiency or by vitamin B12 deficiency.

Microcytic Anemia

A form of anemia manifested as the production of smaller-than-normal red blood cells containing insufficient hemoglobin, which reduces the ability of the red blood cell to transport oxygen; it can result from iron deficiency or vitamin B6 deficiency.

Intrinsic Factor

A protein secreted by cells of the stomach that binds to vitamin B12 and aids its absorption in the small intestine.

Cofactor

A small, chemically simple organic or inorganic substance that is required for enzyme activity; trace minerals such as iron, zinc, and copper function as ______.

Meat Factor

A special factor found in meat, fish, and poultry that enhances the absorption of non-heme iron.

Pernicious Anemia

A special form of macrocytic anemia that is the primary cause of a vitamin B12 deficiency; occurs at the end stage of an autoimmune disorder that causes the loss of various cells in the stomach.

Ferritin

A storage form of iron found primarily in the intestinal mucosa, spleen, bone marrow, and liver.

Hemosiderin

A storage form of iron found primarily in the intestinal mucosa, spleen, bone marrow, and liver.

Antigens

Parts of a molecule, usually large proteins, from microbes, toxins, or other substances that are recognized by immune cells and activate an immune response.

Eicosanoids

Physiologically active signaling molecules, including prostaglandins, thromboxanes, and leukotrienes, derived from the twenty-carbon fatty acids arachidonic acid and eicosapentaenoic acid.

Erythrocytes

Red blood cells; they transport oxygen in the blood.

Iron Depletion

The *first phase* of iron deficiency characterized by a decrease in stored iron, which results in a decrease in blood ferritin levels.

Negative Folate Balance

The *first stage* of folate depletion in which the body has less folate available to it and serum levels of folate begin to decline.

Folate-Deficiency Anemia

The *fourth stage* of folate depletion; a state of severe folate depletion in which there is inadequate folate for a long enough time that the number of red blood cells has declined.

Folate Depletion

The *second stage* of folate depletion in which both serum and red blood cell folate are low.