1. CHAPTER 15 TRACE MINERALS

2. LEARNING OUTCOMES Describe the important food sources, major functions, deficiency and toxicities of each trace mineral discussed in class Understand trace mineral absorption, transportation, storage and excretion. 2

3. OVERVIEW OF TRACE MINERALS Inorganic substances needed by the body in small quantities Includes iron, zinc, copper, maganese, iodine, selenium, chromium, fluoride, and molybdenum Typically difficult to measure in the body and in food 3

4. IRON Foods Heme iron: iron part of hemoglobin and myoglobin in animal flesh Nonheme iron: vegetables, grains, and supplements Needs RDA 18 mg/day adult women, 8 mg/day adult men After menopause drops to 8 mg/day Most common trace mineral deficiency worldwide 4

5. IRON Absorption, Transportation and Excretion Ferritin: iron binding protein in small intestine Storage form of iron, made in response to iron stores Also acts as “mucosal block” Transferrin: protein that binds iron and transports it through body (needs copper) Absorption and storage is tightly regulated in the body because the body has limited ability to excrete absorbed iron Most iron is recycled, only 10% is excreted 5

6. 6 Mucosal “block” Muscle (Myogl ) Bone marrow RBC (Hgb) Liver Non heme must be in Fe 2+ form to be absorbed

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8. IRON Functions Component of proteins Hemoglobin-protein in red blood cells that carries oxygen in body Myoglobin- protein in muscle that carries oxygen to muscles and heart 8

9. IRON Functions Component of enzymes or act as coenzyme Needed for energy metabolism Needed for drug and alcohol metabolism in the liver Needed for neurotransmitter synthesis Needed for immune system 9

10. IRON Deficiency Iron deficiency anemia At risk: premature infants, children, females of child bearing age, vegetarians 10

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12. IRON DEFICIENCY Pale skin, fatigue and weakness. In severe cases, trouble breathing Pica for ice is a very specific symptom Lightheadedness 12

13. IRON UL 45 mg/day Nausea, vomiting, diarrhea, constipation, interfere with absorption of other minerals Who? Supplements (especially kids) Hemochromatosis- genetic disorder that can cause liver disease and heart failure Frequent blood transfusions 13

14. CASE STUDY Betsy just got diagnosed with iron deficiency anemia. What would be a good breakfast? Iron fortified cereal with milk and coffee Spinach and cheese omelet Steak and eggs Ham, egg, and cheese on whole grain bread with OJ 14

15. ZINC Foods Protein rich meat and seafood, whole grains Needs RDA 8-11 mg, most in US get adequate zinc Absorption, Transportation and Excretion Has a mucosal block similar to iron (metallothionein) Not stored, but is recycled Can be excreted in feces, so less toxic than iron 15

16. ZN ABSORPTION 16

17. ZINC Function At least 300 different enzymes require zinc DNA synthesis, immune function, growth and development, home synthesis, antioxidant Deficiency Overt deficiency common in poverty Low appetite, impaired growth, decreased taste, immune dysfunction North America-marginal deficiencies if absorptive diseases, dialysis, vegetarians 17

18. ZINC UL 40 mg/day-usually people who take supplements Low appetite, nausea, vomiting, GI upset 18

19. COPPER Foods Liver, shellfish, nuts, seeds, mushrooms, soy and dark chocolate Needs RDA 900 micrograms daily Deficiency rare Absorption, Transportation and Excretion Little is stored, excreted in feces Binds to metallothione in intestine Copper balance controlled by copper absorption and influenced by iron and zinc status 19

20. COPPER Function Iron metabolism In family of enzymes that act as antioxidants Deficiency rare Menkes disease UL Toxicity is also rare Wilson’s disease 20

21. IS CHOCOLATE GOOD FOR YOU? One study reported that men who ate the most chocolate had a 47 percent lower mortality rate over 15 years than a similar group that consumed little chocolate. Another study that showed a small amount of chocolate slowed platelet clumping. A new chocolate called CocoaVia got a lift from the Journal of the American Dietetic Association, which reported that two (small) bars a day lowered LDL cholesterol in a high- cholesterol subject group by 6.7 percent 21

22. MATCH THE DEFICIENCY WITH THE ANEMIA Vitamin E Folate Vitamin B12 Iron Copper Megaloblastic Microcytic Hemolytic 22 *** See page 548 in book for summary

23. MANGANESE Foods Whole-grain cereals, nuts, legumes and tea Needs AI 1.8-2.3 mg/daily Deficiency rare Absorbed in small intestine, transported with protein carriers, excreted in bile Only ~10% is absorbed, unless need is high Absorbed better if iron status is good 23

24. MANGANESE Function Shares functional similarities with Zinc and Copper (cofactor for enzymes, energy metabolism) Deficiency Rare UL 11 mg/day Inhalation of car emissions Causes nerve damage 24

25. IODINE Foods Saltwater seafood, seaweed, iodized salt, molasses and dairy products Needs RDA is 150 micrograms daily ½ teaspoon of iodized salt meets RDA requirement Absorbed efficiently and stored in thyroid gland, excreted in urine 25

26. IODINE Function Component of thyroid hormone so needed for normal metabolism Deficiency Goiter (enlarged thyroid) and cretinism (poor growth) 26

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28. IODINE UL 110 micrograms/day Enlarged thyroid gland, increased risk of thyroid cancer Japan- high intake of seaweed Chile- high levels in soil 28

29. SELENIUM Foods Seafood, meats, cereal grains and nuts Soil dependent Needs RDA 55 micrograms adults Intake typically above the RDA Easily absorbed, excess is excreted in urine 29

30. SELENIUM Function Anti-oxidant defense network (similar to vitamin E, protects cell membranes from oxidation) Synthesis of thyroid hormone May decrease risk of cancer (especially prostrate and lung) Deficiency No specific disease but deficiency can cause Keshan disease UL 400 micrograms daily Nausea, diarrhea, fatigue, hair loss, change in nails, and skin rashes 30

31. SELENIUM AND CANCER 1) Epidemiology studies show that where selenium levels in the soil are high, death rates from cancer are significantly lower. 2) Clinical trial studies 32,000 men Researchers gave the men either selenium, vitamin E, or a combination of selenium and vitamin E to learn whether either would lower the risk of prostate cancer. This study was suspended early because analysis found no benefit to taking selenium for an average of more than 5 years. 31

32. CHROMIUM Foods Nutrient databases inadequate In many foods including broccoli, processed meats, liver, eggs, whole grain products Needs AI 25-35 micrograms Uncommon deficiency and no UL Functions May improve insulin function and help normalize blood sugar, although supplements have not been shown to be beneficial 32

33. FLUORIDE Foods Fluoridated water, tea, seafood and seaweed Non food sources are toothpaste and mouthwash Needs AI 3-4 mg/daily Easily absorbed and stored in teeth and bones Function Promotes bone and dental health 33

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35. FLUORIDE Deficiency Associated with an increase in dental caries UL.1 mg/kg body weight daily up to 8 years old Most risk is 8 yo or younger Mottling or fluorosis with chronic intake 35

36. MYTHS I drink bottled water, am I missing out on the benefits of Fluoride? Do I need to drink fluoridated water if I brush my teeth? What are other health effects of too much fluoride? 36

37. ULTRA TRACE MINERALS Needed in very small amounts but essential for many enzymes Molybdenum Boron Nickel Silicon Arsenic Vanadium 37