Chapter 12 Lecture The Science of Nutrition Third Edition © 2014 Pearson Education, Inc. Nutrients Involved in Blood Health and Immunity

© 2014 Pearson Education, Inc. Blood Functions –Transports nutrients and oxygen to cells –Removes waste products generated from metabolism

© 2014 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

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Minerals That Maintain Healthy Blood Iron Zinc Copper

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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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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

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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

© 2014 Pearson Education, Inc. Iron Factors that promote iron absorption –Meat factor –Stomach acids –Vitamin C

© 2014 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 approx. 1-10%, vs. typical Western diet's absorption of 14−18%

© 2014 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

© 2014 Pearson Education, Inc. Iron Regulation of total-body iron: –Iron absorption –Iron losses –Storage and recycling of iron

© 2014 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

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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

© 2014 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)

© 2014 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

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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 –Assist in regulating gene expression

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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

© 2014 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

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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.

© 2014 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

© 2014 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)

© 2014 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

© 2014 Pearson Education, Inc. 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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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)

© 2014 Pearson Education, Inc. Vitamins That Maintain Healthy Blood Vitamin K Folate Vitamin B 12

© 2014 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

© 2014 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

© 2014 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

© 2014 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)

© 2014 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 B 12 and B 6 metabolism

© 2014 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

© 2014 Pearson Education, Inc. Folate Four states of folate deficiency: 1)Negative folate balance (stage I) 2)Folate depletion (stage II) 3)Folate deficiency erythropoiesis (stage III) 4)Folate deficiency anemia (stage IV)

© 2014 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

© 2014 Pearson Education, Inc. Folate Folate's role in neural tube defects (NTDs) –Need for folate increases during pregnancy –NTDs = most common malformations of the CNS during embryonic and fetal development –Most common NTD is spina bifida –Biggest challenge: NTDs occur early in pregnancy, sometimes before the pregnancy is known –Hence, adequate folate intake is important for sexually active women of childbearing age

© 2014 Pearson Education, Inc. Folate Folate's role in macrocytic anemia –Macrocytic anemias = larger than normal red blood cells that inhibit adequate oxygen transport –Symptoms include fatigue, irritability, difficulty concentrating, headaches, shortness of breath, reduced capacity for work –Similar symptoms can result from vitamin B 12 deficiency, so it's important to distinguish the cause

© 2014 Pearson Education, Inc. Folate Too much folate –Toxicity can result from supplements –Toxicity can mask vitamin B 12 deficiency –Symptoms: intestinal pain, nausea, vomiting Not enough folate –Macrocytic anemia –Elevated homocysteine –Neural tube defects

© 2014 Pearson Education, Inc. Vitamin B 12 (Cyanocobalamin) Vitamin B 12 is a water-soluble vitamin Functions of vitamin B 12 –Coenzyme for DNA synthesis –Maintains myelin sheath of nerve fibers –Metabolism of amino acid homocysteine

© 2014 Pearson Education, Inc. Vitamin B 12 Factors that alter vitamin B 12 digestion, absorption, and balance –Requires acidic environment (stomach) and protein intrinsic factor for absorption –Stored in the liver –Four levels of vitamin B 12 deficiency

© 2014 Pearson Education, Inc. Vitamin B 12 Recommended intake –RDA for adults is 2.4 µg/day Sources of vitamin B 12 –Found primarily in dairy products, eggs, meats, poultry, fish, and shellfish (animal sources) –Vegan diet may obtain vitamin B 12 from fortified foods, supplements, or injections

© 2014 Pearson Education, Inc. Vitamin B 12 Too much vitamin B 12 –No known adverse effects Not enough vitamin B 12 –Deficiency is rare, but associated with dietary insufficiency or reduced absorption –Gastrointestinal and neurologic effects –Pernicious anemia (lack intrinsic factor) –Macrocytic anemia

© 2014 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

© 2014 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

© 2014 Pearson Education, Inc. A macrophage is a type of nonspecific immune cell. The one shown here is about to engulf an invading microbe.

© 2014 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)

© 2014 Pearson Education, Inc. Immune System Malfunction causes chronic inflammation and infection –Allergic reactions –Autoimmune response –Common in malnourished –Immune deficiency diseases

© 2014 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

© 2014 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

© 2014 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

© 2014 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)

© 2014 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)

© 2014 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