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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 © 2011 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 © 2011 Pearson Education, Inc. © 2011 Pearson Education, Inc. Nutrients Maintain Healthy Blood • • • • • • 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 © 2011 Pearson Education, Inc. © 2011 Pearson Education, Inc. 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 © 2011 Pearson Education, Inc. © 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 © 2011 Pearson Education, Inc. Iron • Factors that promote iron absorption • Meat factor • Stomach acids • Vitamin C © 2011 Pearson Education, Inc. Iron • 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 10%, vs. typical Western diet’s 14−18% © 2011 Pearson Education, Inc. 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 © 2011 Pearson Education, Inc. Iron • Regulation of total-body: • Iron absorption • Iron losses • Storage and recycling of iron © 2011 Pearson Education, Inc. Iron • 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 © 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 © 2011 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) © 2011 Pearson Education, Inc. © 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 © 2011 Pearson Education, Inc. 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. © 2011 Pearson Education, Inc. 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 © 2011 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) © 2011 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 © 2011 Pearson Education, Inc. Copper • Recommended intake • RDA for adults is 900 µg/day • Sources of copper • Organ meats, seafood, nuts, seeds, whole-grain foods © 2011 Pearson Education, Inc. © 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) © 2011 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 © 2011 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 • Impaired dietary fat absorption © 2011 Pearson Education, Inc. 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 © 2011 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) © 2011 Pearson Education, Inc. 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 © 2011 Pearson Education, Inc. 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 © 2011 Pearson Education, Inc. 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 g of folate daily © 2011 Pearson Education, Inc. 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 © 2011 Pearson Education, Inc. Anemia • • • • • 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 © 2011 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 © 2011 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 © 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) © 2011 Pearson Education, Inc. © 2011 Pearson Education, Inc. Immune System • Malfunction causes chronic inflammation and infection • • • • Allergic reactions Autoimmune response Common in malnourished Immune deficiency diseases © 2011 Pearson Education, Inc. 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 © 2011 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 © 2011 Pearson Education, Inc. Overnutrition/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 © 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) © 2011 Pearson Education, Inc. 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) © 2011 Pearson Education, Inc. 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.