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12
Nutrients Involved
in Blood Health and
Immunity
© 2011 Pearson Education, Inc.
Blood
• Functions
• Transports nutrients and oxygen to cells
• Removes waste products generated from
metabolism
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Components of Blood
• Erythrocytes—red blood cells transport
oxygen through the body
• Leukocytes—white blood cells are key to our
immune system
• Platelets—cell fragments assist in blood
clotting
• Plasma—fluid portion of the blood maintains
adequate blood volume
© 2011 Pearson Education, Inc.
© 2011 Pearson Education, Inc.
Nutrients Maintain Healthy Blood
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Iron
Zinc
Copper
Vitamin K
Folate
Vitamin B12
© 2011 Pearson Education, Inc.
© 2011 Pearson Education, Inc.
Iron
• Iron is a trace mineral
• Component of oxygen-carrying hemoglobin
and myoglobin (muscle)
• Component of cytochromes, electron carriers
within the metabolic pathways for energy
production from carbohydrates, fats, and
protein
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© 2011 Pearson Education, Inc.
Maintaining Iron Homeostasis
• Regulation of iron digestion, absorption,
transport, storage, and excretion
• Factors that alter iron digestion and
absorption
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Individual’s iron status
Level of dietary iron consumption
Type of iron in foods
Amount of stomach acid for digestion
Dietary factors enhance or inhibit absorption
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© 2011 Pearson Education, Inc.
Iron
• Two types of iron in foods
• Heme iron—found only in animal-based foods
and more absorbable
• Non-heme iron—not as easily absorbed
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Iron
• Factors that promote iron absorption
• Meat factor
• Stomach acids
• Vitamin C
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Iron
• Factors that impair iron absorption
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Phytate (legumes, rice, and whole grains)
Polyphenols (oregano, red wine, tea, coffee)
Vegetable proteins
Fiber
Calcium
• Bioavailability of iron from vegan diet is 10%,
vs. typical Western diet’s 14−18%
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Iron
• Iron transport
• Transferrin: iron-transport protein in blood
• Receptors on cells transport iron into cells
• Iron storage
• Ferritin and hemosiderin help meet iron needs
• Liver, bone marrow, and spleen
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Iron
• Regulation of total-body:
• Iron absorption
• Iron losses
• Storage and recycling of iron
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Iron
• Recommended intake
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RDA varies based on age and gender
8 mg/day for adult men
18 mg/day for adult women,19−50 years
27 mg/day for pregnant women
• Sources of iron
• Meat, poultry, fish, clams, oysters, liver, enriched
or fortified cereals and breads
• Supplements
© 2011 Pearson Education, Inc.
© 2011 Pearson Education, Inc.
Too Much Iron
• Accidental iron overdose: most common
cause of poisoning deaths in children
• Symptoms: nausea, vomiting, diarrhea
• Hemochromatosis: excessive absorption of
dietary iron and altered iron storage
• Treatment: reduce dietary iron, avoid high
vitamin C intake, blood removal
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Not Enough Iron
• Most common nutrient deficiency in the world
• High risk: infants, young children, adolescent
girls, premenopausal and pregnant women
• Poor dietary intakes
• Iron losses in blood and sweat
• Diets high in fiber or phytates that bind iron
• Low stomach acid
• Poor iron absorption (poor gut health or
dietary supplements with high mineral levels,
e.g., calcium)
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© 2011 Pearson Education, Inc.
Stages of Iron Deficiency
1. Iron depletion is caused by a decrease in
iron stores
2. Iron-deficiency erythropoiesis occurs with
decreased iron transport
3. Iron-deficiency anemia results in reduced
normal, healthy red blood cell production,
decreased size, inadequate hemoglobin
© 2011 Pearson Education, Inc.
© 2011 Pearson Education, Inc.
Zinc
• Zinc is a trace mineral
• Functions of zinc
• Component of enzymes (heme synthesis)
• Maintain structural integrity and shape of proteins
• Assist in regulating gene expression
© 2011 Pearson Education, Inc.
© 2011 Pearson Education, Inc.
Zinc
• Absorption increases with need: growth,
sexual development, pregnancy
• Dietary factors inhibit zinc absorption
• High non-heme iron intake
• Phytates and fiber (whole grains, beans)
• Dietary factor enhances zinc absorption
• Animal-based protein
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Zinc
• RDA: 8 mg/day for women, 11 mg/day for
men
• Sources of zinc
• Red meats, some seafood, whole grains, enriched
grains and cereals
© 2011 Pearson Education, Inc.
© 2011 Pearson Education, Inc.
Zinc
• Too much zinc
• Toxicity can occur from supplements
• Symptoms: intestinal pain, cramps, nausea,
vomiting
• Depressed immune function
• Decreased high-density lipoprotein concentrations
• Interference with copper and iron absorption.
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Zinc
• Not enough zinc
• Deficiencies are uncommon in the United States
• Symptoms: growth retardation, diarrhea, delayed
sexual maturation, hair loss, impaired appetite,
infections
• Lack of good assessment parameters for zinc
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Copper
• Copper is a trace mineral
• Functions of copper
• Required for iron transport
• Cofactor in energy metabolism and for connective
tissue production
• Part of superoxide dismutase antioxidant enzyme
system
• Regulates neurotransmitters (serotonin)
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Copper
• Factors that promote copper absorption
• More copper is absorbed with low-copper diet
• Factors that impair copper absorption
• High zinc intakes
• High iron intakes
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Copper
• Recommended intake
• RDA for adults is 900 µg/day
• Sources of copper
• Organ meats, seafood, nuts, seeds, whole-grain
foods
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© 2011 Pearson Education, Inc.
Copper
• Too much copper
• Toxicity is not well studied in humans
• Symptoms: abdominal pain, nausea, diarrhea,
vomiting, liver damage (Wilson disease)
• Not enough copper
• Copper deficiency is rare
• Symptoms: anemia, reduced white blood cells,
osteoporosis (children—bone demineralization)
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Vitamin K
• Vitamin K is a fat-soluble vitamin important for
both bone and blood health
• Function of vitamin K
• Coenzyme assists in synthesizing blood
coagulating proteins: prothrombin and
procoagulants, factors VII, IX, and X
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Vitamin K
• Factors that promote vitamin K absorption
• Gastrointestinal bacteria produce vitamin K
• Dietary need depends on intestinal health
• Factors that impair vitamin K absorption
• Impaired dietary fat absorption
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Vitamin K
• Recommended intake
• AI for adults is 90−120 µg/day
• Sources of vitamin K
• Green leafy vegetables, such as collard greens,
kale, spinach, cabbage
• Soybean and canola oils
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Vitamin K
• Too much vitamin K
• No known side effects
• Not enough vitamin K
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Deficiency is rare
Blood fails to clot, bleeding, hemorrhaging
Fat malabsorption
Newborns lack intestinal bacteria to produce
vitamin K (injection at birth)
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Folate
• Folate is a water-soluble vitamin
• Functions of folate (coenzyme)
• DNA synthesis, amino acid metabolism
• Cellular division and differentiation
• Functions with B12 and B6 metabolism
© 2011 Pearson Education, Inc.
© 2011 Pearson Education, Inc.
Folate
• Factors that alter folate digestion, absorption,
and balance
• Bioavailability depends on its source: better from
supplements than from food
• Alterations in folate status mimic those of iron
• Four states of folate deficiency
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Folate
• Recommended intake
• RDA : 400 µg/day adults, 600 µg/day during
pregnancy
• Sources of folate
• Fortification to minimize birth defects: enriched
breads, flours, pasta, grain products
• Liver, spinach, lentils, oatmeal, asparagus
• Heat-sensitive; leached out in cooking liquid
© 2011 Pearson Education, Inc.
© 2011 Pearson Education, Inc.
Folate
• Too much folate
• Toxicity can result from supplements
• Toxicity can mask vitamin B12 deficiency
• Symptoms: intestinal pain, nausea, vomiting
• Not enough folate
• Macrocytic anemia
• Elevated homocysteine
• Neural tube defects
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Vitamin B12
• Vitamin B12 is a water-soluble vitamin
• Functions of vitamin B12
• Coenzyme for DNA synthesis
• Maintains myelin sheath of nerve fibers
• Metabolism of amino acid homocysteine
© 2011 Pearson Education, Inc.
© 2011 Pearson Education, Inc.
Vitamin B12
• Factors that alter vitamin B12 digestion,
absorption, and balance
• Requires acidic environment (stomach) and
protein intrinsic factor for absorption
• Stored in the liver
• Four levels of vitamin B12 deficiency
Vitamin B12 Absorption
© 2011 Pearson Education, Inc.
© 2011 Pearson Education, Inc.
Vitamin B12
• Recommended intake
• RDA for adults is 2.4 µg/day
• Sources of vitamin B12
• Available exclusively from animal sources
• Vegan diet may obtain vitamin B12 from fortified
foods, supplements, or injections
© 2011 Pearson Education, Inc.
© 2011 Pearson Education, Inc.
Vitamin B12
• Too much vitamin B12
• No known adverse effects
• Not enough vitamin B12
• Deficiency is rare, but associated with dietary
insufficiency or reduced absorption
• Gastrointestinal and neurologic effects
• Pernicious anemia (lack intrinsic factor)
© 2011 Pearson Education, Inc.
© 2011 Pearson Education, Inc.
Neural Tube Defects
• Folate is required for cell division and proper
formation of the neural tube (develops into
brain and spinal cord)
• Increased early need for folate
• All women capable of becoming pregnant
should consume an additional 400 mg of folate
daily
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Vascular Disease
• Folate and vitamin B12 are required for the
breakdown of amino acid homocysteine
• Low folate and vitamin B12 intake may
increase the level of homocysteine
• High homocysteine levels are associated with
risk for vascular disease
• Adequate folate, vitamin B6, vitamin B12 may
reduce risk for heart attack or stroke
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Anemia
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Anemia (“without blood”)—low hemoglobin
Genetic (sickle cell anemia, thalassemia)
Microcytic anemia: low iron or vitamin B6
Macrocytic anemia: low vitamin B12 or folate
Pernicious anemia: low vitamin B12
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Immune System
• A healthy immune system
• Protects the body from infectious diseases
• Helps heal wounds
• Guards against the development of cancers
• How does it function?
• Nonspecific immune function
• Specific immune function
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Nonspecific Immune System
• Body’s primary defense against microbes,
airborne particles, venom, ingested toxins
• Also called innate immunity
• Intact skin and healthy mucous membranes
• Stomach acid destroys food-borne bacteria
• Inflammatory response causes discomfort,
loss of appetite, fatigue, and fever
© 2011 Pearson Education, Inc.
© 2011 Pearson Education, Inc.
Specific Immune System
• Directed against recognized antigens
• Induces antibodies to destroy invader
• Memory cells remain in circulation
• Two main types of cells: B cells and T cells
• Acquiring specific immunity
• Have disease or vaccinations (immunizations)
• Maternal antibodies
• Antiserum injection (snakebite)
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© 2011 Pearson Education, Inc.
Immune System
• Malfunction causes chronic inflammation and
infection
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Allergic reactions
Autoimmune response
Common in malnourished
Immune deficiency diseases
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Nutrition
• A nourishing diet provides all the nutrients the
immune system needs
• Single-nutrient subclinical deficiencies can
cause subtle abnormalities in immunity
• Protein-energy malnutrition and severe
micronutrient deficiencies reduce immune
function
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Protein-Energy Malnutrition
• Malnutrition increases the risk for infection
• Infection depresses appetite and often causes
vomiting and diarrhea
• Decreased appetite, vomiting, and diarrhea
cause malnutrition, which increases
vulnerability to infection
• Decreased immunocompetence is a sensitive
indicator of reduced nutritional status
© 2011 Pearson Education, Inc.
Overnutrition/Obesity
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Increases incidence of infections
Delays wound healing
Poor antibody response to vaccination
Inflammatory state may increase asthma,
hypertension, cardiovascular disease, and
type 2 diabetes among obese individuals
© 2011 Pearson Education, Inc.
Essential Fatty Acids
• Essential fatty acids are precursors for
signaling molecules eicosanoids
• Omega-6 fatty acids promote inflammatory
response to help contain infection
• Omega-3 fatty acids diminish inflammation in
blood vessels (prevent heart disease)
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Vitamins and Minerals
• Vitamin A maintains mucosal surface
• Vitamins C and E protect cell membrane from
reactive oxygen species
• Zinc assists immune cell gene expression and
enzyme activation (B and T cell proliferation)
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Vitamins and Minerals
• Copper: growth factor for immune cells
• Iron deficiency impairs immune function
• Selenium:
• Coenzyme for glutathione peroxidase
• Promotes B and T cell proliferation
• Antibody production
• Excessive amounts can impair immunity
© 2011 Pearson Education, Inc.