FNH 250: Blood Health Notes PDF

FNH 250: Nutrition Concepts & Controversies BLOOD HEALTH Chapter 14 1. ABOUT BLOOD ......................................................................................................... 2 2. VITAMIN K & BLOOD HEALTH ...................................................................................

FNH 250: Nutrition Concepts & Controversies BLOOD HEALTH Chapter 14 1. ABOUT BLOOD ......................................................................................................... 2 2. VITAMIN K & BLOOD HEALTH ................................................................................. 2 3. TRACE MINERALS & BLOOD HEALTH — Iron, Zinc ................................................ 2 A. INTRODUCTION.................................................................................................................................... 2 B. FACTORS AFFECTING ABSORPTION ................................................................................................ 3 C. TRANSPORTATION & STORAGE ........................................................................................................ 4 D. ROLES ..................................................................................................................................................... 5 E. DEFICIENCY ........................................................................................................................................... 7 F. TOXICITY ................................................................................................................................................ 8 G. FOOD SOURCES ................................................................................................................................... 9 H. SUPPLEMENTS ...................................................................................................................................... 9 I. RECOMMENDATIONS ....................................................................................................................... 10 4. TRACE MINERALS & BLOOD HEALTH — Copper .................................................. 10 A. ABSORPTION....................................................................................................................................... 10 B. ROLES ................................................................................................................................................... 11 C. DEFICIENCY ......................................................................................................................................... 11 D. TOXICITY .............................................................................................................................................. 11 E. FOOD SOURCES ................................................................................................................................. 12 F. RECOMMENDATIONS ....................................................................................................................... 11 FNH 250 Nutrition Concepts & Controversies Blood Health 1. ABOUT BLOOD -only fluid tissue in body -transports nutrients to cells; removes waste products from cells -need appropriate blood quantity and healthy quality -micronutrients are important to blood health -basic components of whole blood: -plasma ~55% of volume -contributes to blood volume -red blood cells (RBC) ~45% of volume -transport oxygen -white blood cells (WBC) <1% of volume -contribute to immune function -platelets <1% of volume -contribute to blood clotting 2. VITAMIN K & BLOOD HEALTH -refer to the detailed set of notes for Vitamin K found in the Bone Health notes -in one of its many roles, vitamin K is required for fibrin, a blood clotting protein -a deficiency can lead to extended bleeding times -an excess can hinder the effects of anti-coagulant drugs (e.g., warfarin) -abundant in diet; bacterial synthesis in GI tract -*green leafy vegetables (e.g., kale, spinach, broccoli, chard), peas, green beans -liver, eggs, milk (cow, not soy) -resistant to losses in cooking Learning Objectives Describe the 4 major components of blood. Describe the role of vitamin K in blood health. 3. TRACE MINERALS & BLOOD HEALTH — IRON, ZINC A. INTRODUCTION IRON (Fe) -total amount of Iron in body 3-4 grams FNH 250: Nutrition Concepts & Controversies Page 2 of 11 FNH 250 Nutrition Concepts & Controversies Page 3 of 11 ~80% of body Fe found in hemoglobin (red blood cells) and myoglobin (muscle) ~5-25% of dietary Iron absorbed -only DRI where adult females (18 mg/day) is greater than adult males (8 mg/day) -Iron deficiency is most common nutrient deficiency in world -Iron is found in 2 oxidation states 2+ = ferrous –more absorbable in the GI tract 3+ = ferric –reduced absorbability -Iron is usually associated with protein in plant and especially animal food sources -fibre and binders such as phytic acid and oxalic acid inhibit absorption -competition for absorption with other divalent minerals, especially with supplemental intakes ZINC (Zn) -total amount of Zinc in body 2-3 grams -high concentrations found in eyes, prostate glands, bone and muscle ~10-35% of dietary Zinc absorbed -Zinc is primarily found in 2+ oxidation state -RDA: 11 mg/day for men; 8 mg/day for women -required as a cofactor by more than 100 enzymes -Zinc is usually associated with protein in plant and especially animal food sources -all cells contain Zinc -Zn competes with Iron and Copper for absorption -Calcium supplements may reduce absorption of Zn, especially at low Zn intake levels -fibre and binders such as phytic acid and oxalic acid inhibit absorption B. FACTORS AFFECTING ABSORPTION IRON & ZINC INCREASED ABSORPTION -**high demand by body (e.g., growth) -Fe: heme-type Iron; Zn: animal foods -stomach acid -low body stores -vitamin C (for non-heme Fe) -meat protein factor (MPF) DECREASED ABSORPTION -full stores in body -phytic acid, oxalic acid (plant foods) -decreased stomach acid -polyphenols (e.g., tannins in tea, caffeine in coffee) -high dietary fibre (~50+ g/day) -supplemental intakes of other minerals (e.g., calcium, phosphorus) at low iron or zinc intakes IRON -once absorbed into the body, Iron is treated like gold -to protect against Iron toxicity, Iron is absorbed only if needed -the process of protecting against excessive Iron absorption is called "MUCOSAL BLOCK" regulation, meaning there is a blockage of Iron absorption at the level of the mucosal cells (also known as intestinal cells, absorptive cells, or enterocytes) -once Fe enters the intestinal cells, it induces the synthesis of a protein called FERRITIN, a storage form of Fe -when iron body pools are full, absorptive cells in the small intestine capture incoming iron, hold it there in the form of ferritin preventing its absorption, and then it is sloughed off when the intestinal cells die (2-3 day life span) and are shed in the feces FNH 250: Nutrition Concepts & Controversies FNH 250 Nutrition Concepts & Controversies Page 4 of 11 -we lose some absorbed Fe every day in urine, sweat and skin shedding, therefore we need to consume daily amounts -absorption is affected by the form of Fe that is found in foods, and the oxidation state of Fe -absorption rates range from 5% (non-heme) to 25% (heme) for healthy adults and 10-35% for Irondeficient people 1. HEME IRON = Iron found in hemoglobin (Hb) and myoglobin (Mb) of animal foods ~25-35% absorbed -represents smaller proportion (~10-15%) of Iron intake from foods -heme Iron absorption can increase 2-fold due to increased need alone 2. NON-HEME IRON = all other forms of Iron in foods; found along with heme Iron in animal foods; only form of Iron found in plant foods ~5-15% absorbed -represents a greater proportion (~85-90%) of Iron intake from foods -non-heme Iron absorption can increase 10-fold due to increased need alone ZINC -MUCOSAL BLOCK regulation protecting against over absorption of Zinc, similar to Iron -Zinc can enter the intestinal cell and either be sloughed off in the feces after 2-3 days or cycled through the body -once Zinc enters the absorptive cell, it induces synthesis of the protein, METALLOTHIONEIN, a storage form of Zinc -metallothionein reduces immediate absorption of excess Zinc, or the Zinc is used by the absorptive cell itself C. TRANSPORTATION & STORAGE IRON -blood TRANSFERRIN = transport protein for Iron in blood -excess Iron is stored in the proteins FERRITIN & HEMOSIDERIN in *liver, spleen, intestinal, bone marrow and red blood cells (RBC) -when Iron stores are low -as Iron is needed, it is transferred from mucosal ferritin to mucosal transferrin in the intestinal cells then on to a different molecule in the blood called blood transferrin for transport to other cells and to bone marrow for incorporation of Iron into hemoglobin (Hb) during RBC synthesis -Hb transports O2 in the blood and eventually RBC are taken up by the liver for storage or breakdown -normal life span of RBC ~120 days -when death or breakdown of RBC occurs, liver salvages Iron and attaches it to blood transferrin and it reenters bloodstream, cycle repeated -Iron is efficiently recycled in the body, thus reducing our dietary need -when blood Iron concentration becomes abnormally high (transferrin is saturated with Fe) -the liver alters ferritin to form a protein called HEMOSIDERIN -hemosiderin releases Iron more slowly than ferritin -bone marrow takes up lots of Iron to make Hb found in RBC -some Iron is stored (ferritin) in bone marrow, some in the liver -as intestinal cells are sloughed off, Iron is lost through GI tract and excreted in feces FNH 250: Nutrition Concepts & Controversies FNH 250 Nutrition Concepts & Controversies Page 5 of 11 ZINC ENTEROPANCREATIC CIRCULATION -intestine receives Zinc from 2 sources: • food • pancreatic secretions -if Zinc is needed by the body, Zinc in the bloodstream (where it is bound to blood transport proteins such as albumin and blood transferrin), circulates through the body (cells taking what they need) to the pancreas where Zinc can enter the lumen of the small intestine via pancreatic digestive juices and can reenter the absorptive cells or not be re-absorbed and excreted in the feces -this loop is called ENTEROPANCREATIC CIRCULATION (‘entero’ means ‘gut’ or ‘intestine’) -pancreas à intestine à blood à pancreas... -METALLOTHIONEIN is the storage form of protein that holds Zinc in the liver until it is needed -if you have an excess of one or the other of Zinc or Iron (i.e., use of supplements, not seen with food intake), transport of the other mineral is jeopardized Learning Objectives Discuss 3 major factors that increase and decrease the absorption of iron and zinc found in foods. Describe differences between heme and non-heme iron, and the impact of each form on the absorption of iron. Describe how the body protects against over-absorption of iron and zinc. Name and describe the process of zinc recycling in the body. D. ROLES IRON a. Release of Energy from the Macronutrients -Iron is required for release of energy at the end of energy-producing cycle in cells (electron transport chain) b. Hemoglobin (Hb) and Myoglobin (Mb) -Iron is an integral part of both hemoglobin and myoglobin -Iron binds oxygen in Hb and Mb making it available for energy production inside cells c. Enzyme Synthesis -Iron needed as a cofactor for the synthesis of many enzymes found in all cells that oxidize compounds -cytochromes in Electron Transport Chain -catalase antioxidant enzyme – degrades hydrogen peroxide FNH 250: Nutrition Concepts & Controversies FNH 250 Nutrition Concepts & Controversies Page 6 of 11 ZINC a. Enzymes ->100 enzymes need Zinc as a cofactor -needed for synthesis of hemoglobin -component of superoxide dismutase – aids in the breakdown of free radicals that cause damage to cell membranes -needed for pancreatic secretion of Zinc-rich digestive juices containing enzymes -aids in the release of vitamin A from the liver, in production of the active form of vitamin A (retinal) in the retina for vision, and in the transport of vitamin A through the action of retinol-binding protein (RBP) -required for DNA synthesis b. Many Body Functions Need Zinc -growth, protein metabolism, wound healing (platelet production) -sexual development -sperm production -taste sensation -gene regulation -thyroid function Other Roles (you are not responsible for learning these roles; not presented in slides) IRON -necessary for immune function -detoxifying pathways in liver -synthesis of: • collagen (basic structure of bone, skin, scar tissue, blood vessels, etc.) • amino acids • hormones • neurotransmitters (substances that allow nerve cell communication) ZINC -proper bone development -proper immune function -synthesis, storage and release of insulin, but not directly involved in the action of insulin -alcohol metabolism -blood clotting Learning Objectives Discuss the role that iron plays in oxygen transport from the lungs to the cells. Describe 2 key roles for iron in the body and 3 key roles for zinc. FNH 250: Nutrition Concepts & Controversies FNH 250 Nutrition Concepts & Controversies Page 7 of 11 E. DEFICIENCY IRON a. Terminology IRON DEPLETION (stage 1) = depleted body stores (ferritin) of Iron; Hb levels in normal range IRON DEFICIENCY (ID; stage 2) = depleted transport (transferrin) of Iron; Hb levels still in normal range; reduced work capacity IRON-DEFICIENCY ANEMIA (IDA; stage 3) = severe depletion of Iron stores that results in a low Hb concentration to the point where there is a reduced oxygen-carrying capacity of the blood and reduced energy-generating capacity in the various tissues; low hematocrit value; fatigue, pale skin, impaired immune function b. IDA Characteristics and Symptoms -characteristics -RBC are lighter red & smaller in size = HYPOCHROMIC MICROCYTIC anemia -these smaller RBC can't carry sufficient oxygen from the lungs to the cells, resulting in compromised energy production in the cells -symptoms -general fatigue, lethargy, impaired work performance -weakness -pale skin (e.g., inside eyelids) -poor tolerance to cold temperatures c. Populations at Risk -all people, except healthy adult males -newborns are born with ~6 month stores (dependent upon mother's status) -infants/preschoolers have a high demand for Iron due to growth -children become restless, irritable and are unable to concentrate -adolescents: males -rapid growth females -onset of menses -women of child-bearing years due to menstrual losses -pregnant women due to increased blood volume, muscle mass and growth needs -athletes have increased iron losses through RBC destruction (esp. runners), increased blood volume, decreased Iron intake from heme sources (vegetarian??) -blood donors -elderly -usually due to lower intake of Iron and poorer absorption d. Prevalence ~15% of North American women are Iron-deficient ~8% of North American women have Iron-deficiency anemia e. Causes of Iron-Deficiency Anemia -poor dietary intake of Iron -heavy menstrual losses -blood donation -ulcers, infection, cancer -pica (consumption of non-food items, e.g., clay, chalk) f. Treatment -supplements -usually ferrous sulphate (Iron in more absorbable 2+ form) FNH 250: Nutrition Concepts & Controversies FNH 250 Nutrition Concepts & Controversies Page 8 of 11 ZINC -Zinc deficiency was recognized in early 1960's in Egypt and Iran -a diet low in animal protein and high in unleavened bread (e.g., pita), legumes, whole grains, beans -pica practiced -symptoms: poor sexual development in male teens, dwarfism -also, in early 1970's, Zinc deficiency observed in patients intravenously fed a formula containing purified amino acids as protein source -impairs digestive processes via ¯ pancreatic secretions, can lead to general malnutrition -impairs immune function -disturbs thyroid function and metabolic rate -compromises vitamin A status affecting macular degeneration in the eye -allows tissue accumulation of Lead a. Vulnerable Groups -pregnant women -alcoholics -children -poor -elderly -adolescent males b. Symptoms -severe growth retardation due, in part, to compromised immune function (infections) -lack of sexual development -slow wound healing -alteration of taste causing a metallic taste in the mouth and loss of appetite -diarrhea, which leads to other nutrient deficiencies Learning Objectives Distinguish between iron-deficiency and iron deficiency anemia. Describe symptoms of long-term zinc deficiency. F. TOXICITY IRON -Iron overload is called HEMOCHROMATOSIS -primary cause (genetic): in some individuals the absorptive cells in the small intestine continuously absorb Fe à blood à liver -secondary cause (lifestyle): e.g., alcoholics due to damage to intestinal cells -Iron is deposited in the heart, pancreas, kidneys and muscle leading to organ damage -bacteria multiply in Fe-rich blood à increased infection -Fe acts as a catalyst in certain reactions that yield free radicals, which damage DNA -this may contribute to initiation of cancer -vitamin C increases Iron absorption into body and release of Iron from ferritin à increased free Iron causes damage (similar to free radicals), therefore, high vitamin C intakes (supplements) can cause Fe to act as a PRO-OXIDANT -people at risk: alcoholics; people with family history of hemochromatosis -symptoms: fatigue, apathy, lethargy, joint pain, constipation, nausea FNH 250: Nutrition Concepts & Controversies FNH 250 Nutrition Concepts & Controversies Page 9 of 11 ZINC a. Effects on Copper and Iron Absorption -high Zinc intake (supplements) reduces Cu and Fe absorption b. Reduction of HDL-Cholesterol (“good” cholesterol) -Zinc intake at levels 3-5X RDA can reduce HDL-C levels by ~15% leading to an increased risk of heart disease -use of Zinc supplements; food intakes safe -symptoms: diarrhea, fever, vomiting, headache -the body rid itself of excess Zinc through pancreatic secretions released into the gut and excreted in the feces (enteropancreatic circulation) G. FOOD SOURCES IRON Iron-Rich Foods ANIMAL FOODS (heme) PLANT FOODS (non-heme) oysters *enriched grain products clams tofu, legumes liver spinach, parsley, sauerkraut meat, fish, poultry -heme Iron has greater bioavailability than non-heme Iron Iron-Poor Foods: milk and milk products; breastmilk Iron Cooking Pots (e.g., cast iron): a source of Iron especially when cooking acidic foods (e.g., tomato sauce) ZINC ANIMAL FOODS *protein-rich (e.g., steak) oysters, clams fish, poultry crab liver milk, yogourt PLANT FOODS wheat germ wheat bran spinach, broccoli mushrooms whole grains (esp. leavened breads) legumes, beans IRON & ZINC BIOAVAILABILTY meat, fish, poultry -high bioavailability grains/legumes -moderate bioavailability vegetables -low bioavailability -e.g., spinach = Iron-rich food but oxalates present bind Iron and decrease its absorption H. SUPPLEMENTS IRON -usually 2+ ferrous form of Iron (e.g., ferrous sulphate or as Iron chelate); therefore, when taken with vitamin C, absorption is not as enhanced as when ferric-based supplements (less common, e.g., ferric citrate) are taken with vitamin C FNH 250: Nutrition Concepts & Controversies FNH 250 Nutrition Concepts & Controversies Page 10 of 11 -usually less well absorbed overall than Iron in foods, because many factors present in foods can aid the absorption of Iron -take between meals and not with milk, tea, coffee, or high fibre foods -may be constipating, take with plenty of fluids -Iron supplements most common cause of young children’s poisoning death; keep Iron supplements out of reach of children ZINC -Zinc gluconate claimed to reduce symptoms and duration of the common cold, especially when taken at the first signs of a cold coming on (e.g., headache, sore throat) -often combined with herb, echinacea -no conclusive evidence to support claims I. RECOMMENDATIONS IRON RDA: Males, all ages: 8 mg/day Females, 19-50 yr: 18 mg/day; 51+ yr: 8 mg/day -usual intakes adequate: Canadian adult males, ~46 mg/day; females, ~34 mg/day -assumes 18% absorption -only RDA that is greater for women (19-50 yr) compared with men, due to regular menstrual losses of iron -adult diet contains roughly 5-7 mg/1000 kcal -vegetarians multiply RDA by 1.8 (ex., 18 mg X 1.8 = 32 mg Fe/day) UL: 45 mg/day ZINC RDA: Males: 11 mg/day; Females: 8 mg/day -usual intakes adequate: Canadian adult males, ~13 mg/day; females, ~10 mg/day -assumes 20% absorption UL: 40 mg/day Learning Objectives List at least 5 rich dietary sources of iron and describe why you think they are good sources. Discuss why there is a difference in iron recommendations for 19-50 year old adult males and females. 4. TRACE MINERALS & BLOOD HEALTH — COPPER A. ABSORPTION ~100 mg Copper in body; 1/3 each in liver, muscle, and other tissues -absorption ~25-40% of intake; inverse proportionality (i.e., higher intakes, lower % absorbed) -Copper in foods enters absorptive cells and induces synthesis of METALLOTHIONEIN protein, a storage protein for Copper and Zinc -high intakes of vitamin C, phytates, or fibre, and supplemental intakes of Zinc or Iron can reduce the absorption of Copper FNH 250: Nutrition Concepts & Controversies FNH 250 Nutrition Concepts & Controversies Page 11 of 11 B. ROLES a. Iron Transport -liver produces a Copper-containing protein, CERULOPLASMIN -ceruloplasmin assists in converting the Fe2+ found in portal blood entering the liver to Fe3+ for transport from liver to other tissues via transferrin (e.g., to bone marrow) -low ceruloplasmin levels cause Fe overload in liver, eventually damage (“rust”) the liver b. Connective Tissue -Copper needed as cofactor for enzymes that help form collagen to strengthen connective tissue and help heal wounds c. Antioxidant Role -Copper is a component of superoxide dismutase antioxidant enzyme system Other Roles (you are not responsible for learning these roles; not presented in slides) -release energy from macronutrients (cytochrome C oxidase in electron transport chain) -synthesizing neurotransmitters (e.g., norepinephrine) -blood clotting -formation and maintenance of the myelin sheath around nerves -proper immune function (white blood cells) C. DEFICIENCY -rare, may be seen in children with protein deficiency and iron deficiency anemia -low ceruloplasmin levels can reduce transport of Fe out of liver, leading to accumulation of Fe in liver, “rusting” of the organ, and damage to the liver -excess Zinc (i.e., supplement use) interferes with Copper absorption -symptoms: anemia, low white blood cell count, poor growth, heart disease, bone loss -may contribute to heart disease by increasing blood cholesterol and damaging blood vessels D. TOXICITY -supplements can cause Cu toxicity F. RECOMMENDATIONS AI: Adults: 900 µg/day -usual intakes adequate UL: 10000 µg/day E. FOOD SOURCES -protein-rich foods ANIMAL FOODS protein-rich liver, organ meats seafood, shellfish -water from Copper pipes PLANT FOODS *whole grains, seeds, nuts *legumes, peanut butter cocoa, dark chocolate dried fruits Learning Objectives Describe the interaction between copper and iron. Explain why humans need copper. Your sister, Jackie, who just turned 20 feels tired and lethargic most days to the point where she frequently foregoes social activities with her friends. What is a possible reason for why Jackie feels this way? Based on your reason, what dietary advice would you give to Jackie? FNH 250: Nutrition Concepts & Controversies