Chapter 12: Nutrients Involved in Blood Health and Immunity © 2017 Pearson Education, Inc.

Blood Functions Transports nutrients and oxygen to cells Removes waste products generated from metabolism Immune function (white blood cells) Mechanism for heat transfer © 2017 Pearson Education, Inc.

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 © 2017 Pearson Education, Inc.

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Micronutrients That Maintain Healthy Blood Minerals Iron Zinc Copper Vitamins Vitamin K Vitamin B6 Folate Vitamin B12 © 2017 Pearson Education, Inc.

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Iron Iron is a trace mineral Component of oxygen-carrying hemoglobin in erythrocytes and myoglobin in muscles Heme groups depend on iron to carry oxygen in hemoglobin Component of cytochromes, electron carriers within the metabolic pathways for energy production from macronutrients Part of antioxidant enzyme system DNA synthesis and cognitive development © 2017 Pearson Education, Inc.

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Maintaining Iron Homeostasis Regulation of iron digestion, absorption, transport, storage, and excretion Factors that alter iron digestion and absorption 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 © 2017 Pearson Education, Inc.

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Iron Two types of iron in foods Heme iron: part of hemoglobin and myoglobin, found only in animal-based foods and more absorbable Non-heme iron: found in both plant and animals, not as easily absorbed Majority of iron in food (90–95%) is nonheme iron Iron in animal-based food is 50–60% heme iron © 2017 Pearson Education, Inc.

Iron (cont.) Factors that enhance iron absorption Meat factor Stomach acids Vitamin C © 2017 Pearson Education, Inc.

Iron (cont.) Factors that impair iron absorption Phytate (legumes, rice, and whole grains) Polyphenols (oregano, red wine, tea, coffee) Vegetable proteins Fiber Calcium Bioavailability of iron from vegan diet is approx. 1–10%, vs. typical Western diet's absorption of 14–18% © 2017 Pearson Education, Inc.

Iron (cont.) Iron transport Ferroportin: transports iron and regulates intestinal absorption and release Transferrin: iron-transport protein in blood Receptors on cells transport iron into cells Iron storage Ferritin (primary) and hemosiderin (overflow) help meet iron needs Liver, bone marrow, and spleen © 2017 Pearson Education, Inc.

Regulation of Total Body Iron Absorption depends on: Amount consumed Amount needed Dietary factors affecting absorption Losses Major loss in turnover of gut enterocytes Lost in feces, menses, blood donations Storage and recycling As cells break down, iron is recycled and returned to body's iron pool © 2017 Pearson Education, Inc.

Iron (cont.) Recommended intake 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 © 2017 Pearson Education, Inc.

© 2017 Pearson Education, Inc.

© 2017 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, chelation drugs © 2017 Pearson Education, Inc.

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) © 2017 Pearson Education, Inc.

Stages of Iron Deficiency Iron depletion (stage I) is caused by a decrease in iron stores Iron-deficiency erythropoiesis (stage II) occurs with decreased iron transport Iron-deficiency anemia (stage III) results in reduced normal, healthy red blood cell production, decreased size, inadequate hemoglobin © 2017 Pearson Education, Inc.

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Zinc Zinc is a trace mineral Functions of zinc Component of enzymes (heme synthesis) Maintain structural integrity and shape of proteins (zinc fingers) Assist in regulating gene expression © 2017 Pearson Education, Inc.

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Zinc (cont.) Metallothionein regulates absorption and release 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 © 2017 Pearson Education, Inc.

Zinc (cont.) RDA: 8 mg/day for women, 11 mg/day for men Sources of zinc Red meats, some seafood, whole grains, enriched grains and cereals © 2017 Pearson Education, Inc.

© 2017 Pearson Education, Inc.

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 © 2017 Pearson Education, Inc.

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 © 2017 Pearson Education, Inc.

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) © 2017 Pearson Education, Inc.

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 © 2017 Pearson Education, Inc.

Copper Recommended intake RDA for adults is 900 µg/day Sources of copper Organ meats, seafood, nuts, seeds, whole-grain foods © 2017 Pearson Education, Inc.

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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) © 2017 Pearson Education, Inc.

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 © 2017 Pearson Education, Inc.

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 and synthesis Impaired dietary fat absorption Excessive broad-spectrum antibiotics © 2017 Pearson Education, Inc.

Vitamin K Recommended intake AI for adults is 90 µg/day for women;120 µg/day for men No established UL at this time Sources of vitamin K Green leafy vegetables, such as collard greens, kale, spinach, cabbage Soybean and canola oils © 2017 Pearson Education, Inc.

Vitamin K Too much vitamin K No known side effects Not enough vitamin K Deficiency is rare Blood fails to clot, bleeding, hemorrhaging Fat malabsorption Newborns lack intestinal bacteria to produce vitamin K (injection at birth) © 2017 Pearson Education, Inc.

Vitamin B6 Essential for heme synthesis Integral part of the heme complex RDA for adults is 1.3 mg/day, 1.5 mg/day for older women and 1.7 mg/day for older men; UL is 100 mg/d © 2017 Pearson Education, Inc.

Vitamin B6 Good sources include meats, poultry, fish, soy-based foods, cereals, and starchy vegetables Deficiency can cause microcytic hypochromic anemia and impairs protein metabolism Toxicity with high-dose supplements, affecting nerves © 2017 Pearson Education, Inc.

Folate One of the B vitamins Folate used for all forms of food folate with biological function, folic acid in supplements, enriched and fortified foods Functions of folate (coenzyme) DNA and amino acid synthesis Cellular division and differentiation Functions with B12 and B6 metabolism © 2017 Pearson Education, Inc.

Folate Recommended intake RDA : 400 µg/day adults, 600 µg/day during pregnancy Sources of folate Fortification to minimize birth defects (neural tube defects): enriched breads, flours, pasta, grain products Liver, spinach, lentils, oatmeal, asparagus © 2017 Pearson Education, Inc.

Folate Four states of folate deficiency similar to iron: Negative folate balance (stage I) Folate depletion (stage II) Folate deficiency erythropoiesis (stage III) Folate deficiency anemia (stage IV) © 2017 Pearson Education, Inc.

Folate Macrocytic anemias are larger than normal red blood cells that inhibit adequate oxygen transport Symptoms (similar to microcytic anemia) include fatigue, irritability, difficulty concentrating, headaches, shortness of breath, reduced capacity for work Similar symptoms can result from vitamin B12 deficiency, so it's important to distinguish the cause © 2017 Pearson Education, Inc.

Vitamin B12 Functions Coenzyme for DNA synthesis Regeneration of folic acid Alterations in status mimic those seen with iron and folate © 2017 Pearson Education, Inc.

Vitamin B12 Recommended intake RDA for adults is 2.4 µg/day Sources of vitamin B12 Found primarily in dairy products, eggs, meats, poultry, fish, and shellfish (animal sources) Vegan diet may obtain vitamin B12 from fortified foods, supplements, or injections © 2017 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 © 2017 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 (destroyed myelin sheaths) Pernicious anemia (macrocytic) results in reduced intrinsic factor production © 2017 Pearson Education, Inc.

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 © 2017 Pearson Education, Inc.

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 © 2017 Pearson Education, Inc.

A macrophage is a type of nonspecific immune cell A macrophage is a type of nonspecific immune cell. The one shown here is about to engulf an invading microbe. © 2017 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) © 2017 Pearson Education, Inc.

Immune System Malfunction causes chronic inflammation and infection Allergic reactions Autoimmune response Common in malnourished Immune deficiency diseases © 2017 Pearson Education, Inc.

Nutrition and the Immune System 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 © 2017 Pearson Education, Inc.

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 © 2017 Pearson Education, Inc.

Obesity 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 © 2017 Pearson Education, Inc.

Essential Fatty Acids Essential fatty acids are precursors for signaling molecules eicosanoids Supplementation with EPA and DHA reduces inflammation and may treat chronic inflammatory conditions like rheumatoid arthritis, inflammatory bowel disease, and cardiovascular disease © 2017 Pearson Education, Inc.

Vitamins and Minerals Vitamin A maintains mucosal surface Vitamins C and E protect cell membrane from reactive oxygen species Zinc important for immune function, gene expression and enzyme activation (B and T cell proliferation) © 2017 Pearson Education, Inc.

Vitamins and Minerals (cont.) Selenium: Coenzyme for glutathione peroxidase Promotes B and T cell proliferation Antibody production Iron and copper: Part of superoxide catalase and dismutase Deficiencies reduce immune response (B and T cell function) Excessive iron can impair immunity © 2017 Pearson Education, Inc.

Infections Alter Nutrient Status Reduced food intake: illness/infection reduces appetite and overall energy intake Increased nutrient loss (diarrhea, vomiting, inflammation) Increased resting metabolic rate with fever Redistribution of energy and nutrients to enhance the immune response © 2017 Pearson Education, Inc.