Science of Nutrition Ch. 12

Blood in Maintaining Health

A. Blood transports nutrients, oxygen, and waste products.
B. Blood is comprised of four components.
1. Erythrocytes transport oxygen.
2. Leukocytes are the key to the immune system.
3. Platelets assist in formation of blood clots.
4. Plasma is the fluid

Blood - Nutrients that maintain healthy blood

Iron is a trace mineral,
Zinc is a trace mineral.
Copper is a trace mineral.
Vitamin K is a fat-soluble vitamin important to blood and bone health.
Folate is a water-soluble B-vitamin
Vitamin B12 is a water-soluble B-vitamin that contains cobalt.

Iron is a trace mineral,

A. Iron is a trace mineral, but iron deficiency is the most common nutrient deficiency in the world.
1. Iron functions as a component of many proteins.
a. Almost two-thirds of our body iron is found in hemoglobin.
i. Iron acts as a shuttle, picking up oxy

Zinc is a trace mineral.

Zinc is a trace mineral.
1. Functions of zinc are divided into three categories.
a. As a coenzyme for approximately a hundred different enzymes, zinc assists in:
i. hemoglobin production
ii. generating energy
iii. digestion
iv. bone health
b. Zinc helps p

Copper is a trace mineral.

Copper is a trace mineral.
1. Copper has several important functions.
a. Copper is a component of ceruloplasmin, which oxidizes iron so that it can be transported to plasma.
b. Copper is a cofactor in many metabolic pathways.
c. Copper is involved in regu

Vitamin K is a fat-soluble vitamin important to blood and bone health.

Vitamin K is a fat-soluble vitamin important to blood and bone health.
1. Vitamin K functions as a coenzyme for proteins involved in blood clotting.
2. What factors alter vitamin K absorption and balance?
a. Any factor that reduces bacterial production of

Folate is a water-soluble B-vitamin

Folate is a water-soluble B-vitamin, known as folic acid in the supplemental form.
1. Folate-dependent coenzyme functions in DNA synthesis, cell differentiation, and amino acid metabolism.
a. Folate is critical to the proper development of the embryo.
b.

Vitamin B12 is a water-soluble B-vitamin that contains cobalt.

Vitamin B12 is a water-soluble B-vitamin that contains cobalt.
1. Vitamin B12 has several important functions.
a. It is part of coenzymes that assist with DNA synthesis.
b. It helps maintain the myelin sheath.
c. Along with folate and B6, it prevents the

Blood Health - disorders from inadequate intake of nutrients

Neural tube defects are the most common
Vascular disease and homocysteine are linked.
Anemia

Neural tube defects are the most common

Neural tube defects are the most common malformations of the central nervous system that occur during fetal development.
1. To prevent neural tube defects, women of child-bearing age should consume 400 �g of folate daily.

Vascular disease and homocysteine are linked.

Vascular disease and homocysteine are linked.
1. Consuming adequate amounts of folate and vitamin B12 are important to lower homocysteine levels

Anemia

Anemia refers to any condition in which hemoglobin levels are low.
1. Microcytic anemia is caused by a deficiency of iron or vitamin B6.
a. Red blood cells produced in an iron-deficient environment are smaller than normal and contain inadequate hemoglobin

Immune System, and How Does It Function

Nonspecific immune function protects against all potential invaders.
Specific immune function
Immune system malfunction

immune function - nonspecific- protects against all potential invaders.

Nonspecific immune function protects against all potential invaders.
1. Tissues, mucus, and enzymes are involved in nonspecific immunity.
a. Skin and mucous membranes block invaders from entering organs and deeper tissues.
b. Coughing, sneezing, vomiting,

immune function - specific

Specific immune function protects against identified antigens.
1. The first time the immune system encounters an antigen it produces a primary immune response and memory cells.
2. Two main types of lymphocytes provide specific immunity.
a. B cells produce

Immune system malfunction

Immune system malfunction can cause chronic inflammation and infection.
1. During allergic reactions, harmless proteins in the environment or in food are mistaken for pathogens.
2. In autoimmune diseases, the body's own proteins are mistaken for pathogens

Immune System- nutrition affects

Protein/energy malnutrition impairs immune function.
1. Since immune response requires energy and amino acids, malnourished individuals suffer from anergy.
2. Even moderate nutrient deficiencies impair immune function; hence, immunocompetence is an indica

Protein/energy malnutrition impairs immune function.

1. Since immune response requires energy and amino acids, malnourished individuals suffer from anergy.
2. Even moderate nutrient deficiencies impair immune function; hence, immunocompetence is an indicator of nutritional status.

Overnutrition and obesity

Overnutrition and obesity increase incidence and severity of infections.
1. Mechanisms underlying lower immune function in obese individuals are unclear.
2. Immune function appears to improve with weight loss.
3. The low-grade inflammatory state present i

Essential fatty acids

Essential fatty acids make signaling molecules for the immune system.
1. Omega-6 fatty acids produce inflammatory mediators.
2. Omega-3 fatty acids help relieve inflammation.
a. Omega-3 fatty acids diminish inflammation in lupus, Crohn's disease, ulcerati

vitamins and minerals

Certain vitamins and minerals are critical to a strong immune response.
1. Vitamin A protects the barrier function of the mucosa.
a. Vitamin A supplementation in populations with low vitamin A status reduces incidence and fatality from a variety of infect

minerals and vitamins

Certain vitamins and minerals are critical to a strong immune response.
1. Vitamin A protects the barrier function of the mucosa.
a. Vitamin A supplementation in populations with low vitamin A status reduces incidence and fatality from a variety of infect

phytochemicals

Nonnutrient phytochemicals in plant-based foods can enhance resistance to disease.
1. It is likely that antioxidant phytochemicals protect against chronic inflammation and reduce the risk for inflammatory diseases of aging.
2. Many herbs are commonly thou

Probiotics and prebiotics

Probiotics and prebiotics may enhance immune function.
1. Probiotics, foods or supplements that contain live bacteria, are thought to protect against pathogens by:
a. colonizing the gut to keep pathogens from adhering to the lining
b. producing metabolite

Prebiotics and probiotics

Probiotics and prebiotics may enhance immune function.
1. Probiotics, foods or supplements that contain live bacteria, are thought to protect against pathogens by:
a. colonizing the gut to keep pathogens from adhering to the lining
b. producing metabolite

Blood - maintain health

transport system
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Blood - nutrients

Iron
Zinc
Copper
Vitamin K
Bitamin B12
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Erthrocytes

Red blood cells that trasport oxygen from the lungs to the body and carbon dioxidefrom the cells to the lungs.
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Lukocytes

white blood cells
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Platelets

Tiny, disk-shaped bodies in the blood, important in blood clot formation
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Plasma

colorless watery fluid of blood and lymph containing no cells and in which erythrocytes and leukocytes and platelets are suspended
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Coenzyme

An organic molecule serving as a cofactor. Most vitamins function as coenzymes in important metabolic reactions
most vitamin b's
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Cofactor

Any nonprotein molecule or ion that is required for the proper functioning of an enzyme.
trace minerals like iron zinc and copper funcgtion as cofactors
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Iron

F e
trace mineral
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Iron function

Carries oxygen as part of hemoglobin in blood or myoglobin in muscles; required for cellular energy metabolism
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Iron RDA

men: 8 mg/day
women: 18 mg/day
pregnant women: 27 mg/day
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Hemoglobin

a hemoprotein composed of globin and heme that gives red blood cells their characteristic color
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Myoglobin

An oxygen-storing, pigmented protein in muscle cells.
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Heme

a complex red organic pigment containing iron and other atoms to which oxygen binds
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Iron homeostasis

How does iron regulate its own absorption, transport, and storage?
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Heme iron

Iron obtained from meat, poultry, or fish sources; the form most usable by the body.
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non heme iron

iron in plants and animal foods that is not part of hemoglobin or myoglobin
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Iron transport

1) Across cell membrane (ferroportin)---oxidized to Fe3+ (requires copper)
2) Transferred (Transferrin)
3) Stored (ferritin)----bone marrow, spleen, liver
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Ferroportin

located on basolateral surface of enterocytes
transports ferrous iron out of cell into extracellular fluid
reduced intestinal expression causes severe iron deficiency
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Hephaestin

Copper ferroxidase, acts with ferroportin in iron transport.
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Ceruloplasmin

a glycoprotein that carries most of the copper in the blood
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Iron storage

liver, bone, marrow, and spleen
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Ferritin

a protein containing 20% iron that is found in the intestines and liver and spleen
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Hemosiderin

This is an iron-containing pigment derived from hemoglobin from disintegration of red blood cells. It is one form in which iron is stored until it is needed for making hemoglobin.
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Iron Regulation

Iron is a vital yet potentially toxic substance
So mammalian cells have evolved an elegant way to regulate iron assimilation
An RNA-binding protein known as the iron regulatory protein (IRP) plays a key role
It influences both the ferritin mRNA and the tr

Transferrin

a globulin in blood plasma that carries iron
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Iron RDA

men: 8 mg/day
women: 18 mg/day
pregnant women: 27 mg/day
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Iron Food Sources

Red meats, fish, poultry, shellfish, eggs, legumes, dried fruits
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Iron overdose

DIARRHEA, METABOLIC ACIDOSIS
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Iron deficiency

Anemia characterized by an inadequate amount of iron in the body to produce hemoglobin
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Iron depletion

the first stage of iron deficiency, caused by a decrease in iron stores
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Iron deficiency erythropoiesis

stage II of iron deficiency
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Zinc

Zn�?
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trace mineral

Zinc function

Essential for the activity of 100+ enzymes.
Important in the formation of zinc fingers (transcription factor motif)
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Iron deficiency anemia

a form of anemia due to lack of iron in the diet or to iron loss as a result of chronic bleeding
Stage III
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Zinc structural function

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Zinc Regulatory functions

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Zinc - digeston, absorption and balance

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Metallothionein

a sulfur-rich protein that avidly binds with and transports metals such as zinc
homoestasis
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Zinc transportation

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Zinc RDA

(19-50) Men = 11mg/day, Women = 8mg/day
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Copper RDA

(19-59) Men = 900 ug/day, Women = 900 ug/day
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Folate RDA

400 ug/day for adults as DFE : dietary folate equivalents
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Vitamin B 12 RDA

19-50 2.4 ug/ day

Copper

helps make red blood cells; helps build protein; helps the body use iron
trace mineral
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Copper function

metalloenzyme, necessary for iron absorption and use of iron in hemoglobin formation (catalyzes oxidation of ferrous iron to ferric iron)
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Copper absorption

most absorbed by small intestine, 50%+ is absorbed
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Copper balance

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Copper toxicity

vomiting, liver damage
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Copper deficiency

iron deficiency; poor wound healing (cofactor lysyl oxidase); aortic dissection
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Folic Acid function

Important for synthesis of nitrogenous bases in DNA/RNA.
Converted to tetrahydrofolate (THF), a conezyme for 1-carbon transfer/methylation reactions.
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Folate function

462, - single carbon transfers
- homocysteine --> methionine
- part of the coenzymes THF and DHF used in DNA synthesis

Homocysteine

a blood test used to measure the amount of homocysteine in the blood
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Folate

a B vitamin that is essential for cell growth and reproduction
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Folate toxicity

masks vitamin B12 deficiency
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Negative folate balance / Stage I

the first stage in folate deficiency, in which serum levels of folate begin to decline
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Folate Depletion / Stage II

the stage of folate deficiency accompanied by low serum and red blood cell folate, with slightly elevated serum homocystein concentrations
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Folate deficiency erythropoiesis / Stage III

the stage of folate deficiency, in which folate levels are so low that the ability to synthesize new red blood cells is inhibited
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Folate deficiency anemia / Stage IV

the stage of folate deficiency, in which the number of red blood cells has declined due to a lack of folate, and macrocytic anemia develops
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Macrocytic anemia

anemia in which the average size of erythrocytes is larger than normal
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Neural tube defects

malformations of the brain, spinal cord, or both during embryonic development that often result in lifelong disability or death
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B12

cyanocobalamin
, forming cells, nervous system
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B12 functions

Coenzyme in all body cells
Nucleic acid synthesis
Neural function - odd chain fatty acids required for myelin
Amino acid synthesis
Blood cell formation
DNA synthesis
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B12 absorption / balance/ metabolism

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Intrinsic factor

a substance produced by the mucosa of the stomach and intestines that is essential for the absorption of vitamin B12
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Atrophic Gastritis

a condition, frequently seen in individual over the age of 50 years, in which stomach-acid secretion is low
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B12 deficiency

Macrocytic, megaloblastic anemia; neurologic Sx (paresthesias, subacute combined degeneration) due to abnormal myelin. Prolonged deficiency leads to irreversible nervous
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Vascular disease and homocysteine

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Anemia

a deficiency of red blood cells
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Microcytic Anemias

iron deficiency MC, anemic chronic disease, thalassemia, sideroblastic anemia
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Macrocytic Anemias

� MCV > 100
� Impaired DNA synthesis ? maturation of nucleus delayed relative to maturation of cytiplasm
� Megaloblastic (Folate/B12) vs. Non-Megaloblastic
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Pernicious Anemia

lack of mature erythrocytes caused by inability to absorb vitamin B12 into the body
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Autoimmune

immune reaction directed against a person's own tissue
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Nonspecific immune function

generalized body defense mechanisms that protect against the entry of foreign agents such as microorganisms and allergens; also called innate immunity
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Immunine system

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Specific immune function

the strongest defense against pathogens. requires adaptation of lymphocytes that recognize antigens and that multiply to protect against the pathogens carrying those antigens, also called adaptive immunity or acquired immunity
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Antigens

substances that are recognized by the immune system as foreign to the body and that induce it to produce antibodies to defend against them
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Memory Cells

Cells that remember a particular antibody
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B cells

A white blood cell that make antibodies
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T cells

an immune system cell that coordinates the immune system and attacks many infected cells
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Plasma cells

Cells that develop from B cells and produce antibodies.
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Anitbodies

specialized proteins that destroy infectious agents
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Cytotoxic T cells

T cells that can kill other cells. Almost all cytotoxic T cells are CD8 T cells. Cytotoxic T cells are important in host defense against viruses and other cytosolic pathogens, because they recognize and kill the infected cells.
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Vaccinations

a weak or dead sample of a pathogen that is put into the body to prepare it's immune system
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Antiserum

blood serum containing antibodies against specific antigens
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Immunocompetence

The ability of the body to produce a normal immune response (i.e., antibody production and/or cell-mediated immunity) following exposure to an antigen.
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Eicosanoids

Lipids that exert complex control over many bodily systems, mainly in inflammation or immunity, and as messengers in the central nervous system.
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