Outline

1. Welcome to Seminar on IronMeera Kaur, PhD, RDAssistant ProfessorDepartment of Family MedicineFaculty of Medicinekaur@cc.umanitoba.cahttp://home.cc.umanitoba.ca/~kaur

2. 2 Outline • Learning Objectives • Introduction • Physiochemical Properties • Functions • Food Sources • Absorption • Recommended Dietary Allowances • Deficiency • Toxicity • Conclusions • Questions and Answers

3. 3 Learning Objectives • Physicochemical properties • Biological functions • Metabolism • Food sources and Dietary Reference Intakes • Deficiency and toxicity • The global scenarios

4. 4 Introduction • Iron, one of the most abundant metal on earth, is found in every living cell • Total body content of iron is 5g • About 2/3rd of iron in the body is found in hemoglobin (Hb)

5. 5 Physiochemical Properties • Pure iron is lustrous, silvery and easily rusts in damp air • Solid at 200C • Melting point: 15350C or 27950F • Conducts heat and electricity and forms positive ions in its chemical reactions • Pure iron is fairly soft and can easily be shaped and formed when hot • Soluble in low pH (acid medium)

6. 6 Functions of Iron... • Iron plays important role in • Immune function • Cognitive development • Temperature regulation • Work performance Other physiological functions of iron are…

7. 7 Functions of iron... • Iron is important constituent of body protein… • hemoglobin • gives ability to carry O2 fromlung to all tissues • assists in the transport of CO2 back to lungs for expiration • How O2 carrying capacity of blood is regulated? • When the O2 carrying capacity of blood is declined, kidney produces a hormone—Erythropoietin, which targets bone marrow to produce more red blood cells (RBC) and stimulates RBC release from the bone marrow

8. 8 Functions of iron... • Iron is important constituent of body protein… • myoglobin • provides Oxygen to skeletal and heart muscle • Acts as a cofactor for many biological reactions • Cytochrome: in Electron transport chain helps transport electron to molecular O2 • Cytochrome P-450: Oxidative degradation of drugs • Mitochondria: helps conversion of citrate to isocitrate, the first step of energy production in the body

9. 9 Functions of iron...(cofactor) • works with other enzymes to synthesize collagen, neurotransmitters(dopamine,epinephrine,nonepinephrine, serotonin) and eicosanoid Iron works through life cycles

10. 10 Food Sources • Two forms of dietary iron: Heme and Nonheme • Heme: Food from animal origin (meat, fish, poultry etc.) • absorbed better than the nonheme iron • Nonheme: grains and food from vegetable origin (cereal, legumes, vegetables, molasses, blackstrap etc.) • most dietary iron is nonheme iron that are bound to some other organic constituent of the food. • Cooking tends to break these interactions and increase iron availability. Please refer to the handout for food sources of heme and nonheme iron

11. 11 Absorptions… • Body uses variety of mechanisms to absorb and distribute iron in the body • Heme iron absorbs directly into the absorptive cell • Intestinal mucosal cells in the duodenum and upper jejunum absorb the iron. • Heme iron is better absorbed than non heme iron • Low pH enhances iron absorption • Phytates, tannins and antacids block iron absorption. • No physiologic mechanism for excretion of excess iron from the body other than blood loss (i.e., pregnancy, menstruation or other bleeding.) • Mucosal block and hemosiderin will prevent iron toxicity.

12. 12 Factors affecting iron Absorption… • Increases Absorption Decreases absorption • Gastric acid, Low pH – Phytic acid (dietary fiber) • Heme form of iron – Oxalic acid (leafy veg) • High body demand – Polyphenol (tea, coffee) • Low body stores – Full body stores of iron • Meat Protein Factor – Excess of Zn, Mn, Ca • Vitamin C – Reduced gastric acid output – Some antacids

13. 13 Absorptions Cell membrane of brush border Stomach Small Intestine (Duodenum and Jejunum) Fe+++ Mucus membrane Brush border of Absorptive cells Fe+++ Fe +++ + MBP  Fe++ MBP Blood Liver Ceruloplasmin Stored as Ferritin Absorptive cells Iron+ Apoferritin Iron + Transferrin Mucosal Block Endocytosis Receptor cell Lysosome Free iron Various sites Reduces iron toxicity Binds iron Hemosiderin If excess iron 

14. 14 Recommended Dietary Allowances(mg/d) • Age Males Females Pregnancy Lactation • 0 to 6 months 0.27* 0.27* (* Adequate intake) • 7 to 12 months 11 11 N/A N/A • 1 to 3 years 7 7 N/A N/A • 4 to 8 years 10 10 N/A N/A • 9 to 13 years 8 8 N/A N/A • 14 to 18 years 11 15 27 10 • 19 to 50 years 8 18 27 9 • 51+ years 8 8 N/A N/A

15. 15 Deficiency… • WHO considers iron deficiency to be the number one nutritional disorder in the world • Eighty per cent of the world population may be iron deficient, while 30% may have Iron Deficiency Anaemia (IDA)-- also known as hypochromic microcytic anaemia • IDA can be detected by measuring hematocrit – the % of blood volume occupied by RBC (normal: <34-37%) and the Hemoglobin in blood (<10-11%)

16. 16 Deficiency…IDA • IDA Associated with • Low dietary intake • Inadequate absorption • Excess blood loss • Vitamin A deficiency (helps mobilize Fe from the storage site), especially common in the developing countries • Chronic malabsorptions such as inflammatory bowel diseases

17. 17 Deficiency… • Who are at risk for developing IDA? • Women of childbearing age • Pregnant women • Low birth weight infants • Older infants and toddlers • Teenage girls • Individuals with kidney failure (on Dialysis) because failing kidneys cannot produce enough erythropoietin to make RBC in the blood • Intestinal worm infestation (hook worm etc.) • YYY

18. 18 Deficiency Symptoms… • Symptoms of IDA • Lack of energy or tiredness • Extreme fatigue and feeling of weakness • Pale skin • Light headedness, headache • Pale skin on the lining of the eyes, the inner mouth and the nails • Rapid and forceful heartbeat • Low blood pressure with position change from sitting to standing up • YYY

19. 19 Deficiency Symptoms… • Symptoms of IDA • Finger nails that become thin, brittle and white may grow abnormally with a spoon-shaped appearance • Tongue may become sore, smooth and reddened • Decrease in appetite • Shortness of breath during exercise • Decreased immune function and increased vulnerability to infection • A strong desire to eat nonfoods such as ice, paint or dirt (a condition called Pica) • Disturbed sleep and abdominal pain • YYY

20. 20 Deficiency (blood picture)… These red cells are hypochromic and microcytic due to iron deficiency

21. 21 Deficiency Symptoms… • YYY

22. 22 Deficiency Symptoms…

23. 23 Deficiency Symptoms…

24. 24 • “Mary - a case study” • Mary, a 14 year old girl, was feeling tired all the time. She had brittle nails and sore tongue as well. She went to her physician. Her physician ordered some blood test. After a week her physician called her back to clinic and prescribed Iron tablet for her. He also advised Mary to eat foods rich in vitamin C. • Q. 1. Why Mary was feeling tired? • Q. 2. Why Mary’s doctor Prescribed Iron tablets? • Q. 3. Why Mary’s doctor advised her to eat foods • rich in vitamin C?

25. 25 Toxicity/Overload • Two kinds • Hemochromatosis • Genetic disorder. Causes liver, heart and other organ damage. Absorbs iron three times more than normal. Common treatments are blood donation and drugs that bind iron. Common amongst Asian/ Asian Islanders • Hemosiderosis • Accumulation of hemosiderin (insoluble storage iron due to frequent blood transfusion or long-term consumption of large amount of iron. Can affect lung, liver, heart and other vital organs

26. 26 Conclusions • Iron -- an important trace mineral • is needed by everybody throughout the life cycles • Is absorbed in the duodenum and jejunum • is part of hemoglobin and myoglobin that carry oxygen throughout the body. • carries many other important physiological functions • is stored in liver, spleen and other tissues and it is an essential part of many of body's proteins and enzymes. • deficiency of which causes Iron Deficiency Anaemia ─ one of the most common nutritional disorders around the globe. • that our body cannot excrete if overloaded and results in hemochromatosis and hemosiderosis. • YYY

27. 27 Thank you for attending the classAny question?