The Trace Minerals

1. The Trace Minerals Chapter 13

2. The Trace Minerals – An Overview • Food sources • Depend on soil and water composition • Depend on food processing • Deficiencies • Can affect people of all ages • May be difficult to recognize • Toxicities • FDA regulation of supplements

3. The Trace Minerals – An Overview • Interactions • Common and well coordinated to meet needs • May lead to nutrient imbalances • Excess in one may cause a deficiency of another • Interfere with work of minerals • Contaminant minerals causing toxic reactions • Research of trace minerals is active, suggesting there is more to learn.

4. Iron • Too little and too much can be harmful • Roles in the body • Switches back and forth between two forms • Ferrous iron (reduced state) • Ferric iron(oxidized state) • Cofactor in oxidation-reduction reactions • Widespread in metab; enzymes making aa, collagen, hormones, & neurotransmitters • Part of electron carriers • Form water & produce ATP • Hemoglobin and myoglobin • 2 proteins found in RBC & muscle cells

5. Iron (Fe) • Absorption • Body conserves iron • Balance maintained primarily through absorption • Ferritin • Iron-storage in small intestine • When Fe is needed ferritin releases some Fe to an Fe support protein called • Transferrin • Iron transport protein

6. Iron Absorption

7. Iron • Absorption • Dietary sources • Heme iron (animals) • Nonheme iron (plant & animal) • Absorption-enhancing factors • MFP factor • Peptide that promotes absorption of nonheme Fe from other foods eaten at same meal • Vitamin C • Some acids and sugars

8. Heme and Nonheme Iron in Foods

9. Iron • Absorption-inhibiting factors • Phytates • Vegetable proteins • Calcium • Polyphenols • Dietary factors combined; MFP & vit C as enhancers & phytates as inhibitors • Individual variation in absorption • Health, stage in life cycle, and iron status

10. Iron • Iron Transport and Storage • Surplus is stored in bone marrow, spleen, and liver. • Hemosiderinis a storage protein used when concentrations of iron are extremely high. • Storing excess iron is a protective measure because iron can act as a free radical. • Iron Recycling • The liver and spleen dismantle red blood cells and package iron into transferrin. • Transferrincarries iron in the blood. • Bone marrow incorporates iron into hemoglobin and stores iron as ferritin. • Iron-containing hemoglobin carries oxygen in the blood. • Iron is lost when bleeding occurs and through the GI tract. • Iron Balance • The absorption, transport, storage, recycling, and loss of iron must be regulated in order to maintain iron balance. • Hepcidinis a hormone that inhibits the absorption and transport of iron to keep blood levels within normal ranges.

11. Iron • Deficiency • Most common nutrient deficiency worldwide • Populations affected in U.S. • 10% toddlers, adolescent girls, and women of childbearing age • Link with being overweight • Vulnerable stages in life • Women in reproductive years • Pregnancy • Infants and young children • Adolescence

12. Iron • Deficiency • Blood losses • Assessment of deficiency • Deficiency develops in stages • Iron stores diminish – serum ferritin • Decrease in transport iron – transferrin • Iron deficiency – hemoglobin and hematocrit values

13. Iron • Iron deficiency and anemia • Deficiency – depleted iron stores without regard to degree of depletion • Anemia – severe depletion of iron stores • Low hemoglobin concentrations • Pale & small RBCs (hypochromic, microcytic)

14. Iron • Deficiency and behavior • Energy metabolism is impaired • Neurotransmitter synthesis is altered • Reduces work capacity and mental productivity • Motivational problems • Pica • Craving and consumption of nonfood substances

15. Iron • Toxicity • Hereditary hemochromatosis • (Most common genetic disorder in U.S.) • Genetic failure to prevent unneeded iron in the diet from being absorbed • Hormone hepicidin supports homeostasis and absence/ineffectiveness causes hemochromatosis • Hemosiderosis • Deposits of iron-storage pro hemosiderin in liver, heart, joints, and other tissues

16. Iron • Symptoms of iron overload include: • infections, fatigue, joint pain, skin pigmentation, and organ damage. • Problems include liver tissue damage and infections. • Higher risk of diabetes, liver cancer, heart disease, and arthritis. • More common in men then in women. • Treated with chelationtherapy • Use of EDTA to bind with metallic ions, thus healing the body by removing toxic metals

17. Iron • Heart disease • Excess iron • Free radicals • Cancer • Free-radical damage • Iron poisoning • Symptoms of toxicity • UL

18. Iron • Iron and Heart Disease • may be a link to high iron stores. • Iron and Cancer • may be a link with free radical activity resulting in damage to DNA. • Iron Poisoning • UL for adults: 45 mg/day. • Accidental supplement poisoning in children. • Symptoms include nausea, vomiting, diarrhea, rapid heartbeat, weak pulse, dizziness, shock, and confusion.

19. Iron • Recommendations and sources • Select iron-rich foods • Natural – meats, fish, poultry, legumes, eggs • Enriched – flour and grain products • RDAs • RDA Men: 8 mg/day for adults 19-50 years of age. • RDA Women: 18 mg/day for adults 19-50 years of age. • RDA Women: 8 mg/day for adults over 51 years of age. • Vegetarians need 1.8 times as much iron because of low bioavailability. • Maximizing absorption • Bioavailability is • high in meats, fish, and poultry. • intermediate in grains and legumes. • low in vegetables. • Combined effect of enhancing and inhibiting factors.

20. Iron • Contamination & supplementation • Iron cookware • Iron content of foods • Supplements • Groups that may need supplements • Enhancing absorption • Vitamin C • Physician prescription

21. Zinc • Roles in body • Gene expression • Cell membranes • Immune function • Growth & development • Synthesis, storage, and release of insulin • Blood clotting • Thyroid hormone function • Behavior & learning performance • Visual pigment • Taste perception • Sperm production Zn def impairs all these and other functions, underlining the vast importance of Zn in supporting the body’s proteins.

22. Zinc • Absorption • Rate varies depending on zinc status • Dietary factors • Upon absorption • Zn can participate in metabolic function of intestinal cells itself or may be retained with the intestinal cells by metallothionein until the body needs Zn • Recycling • Small intestine • Two doses of zinc (food/meals & Zn-rich pancreatic secretions) • Enteropancreatic circulation travels from the pancreas to the intestines and back. • Zinc losses • occur in the feces, urine, shedding of skin, hair, sweat, menstrual fluids, and semen.

23. Zinc • Transport • Transported by the protein albumin. • Binds to transferrin. • Excessive iron and copper can lead to a zinc deficiency and excessive zinc can lead to an iron and copper deficiency • Zinc Deficiency • Not widespread. • Occurs in pregnant women, young children, the elderly, and the poor. • Symptoms of deficiency: • Growth retardation • Delayed sexual maturation. • Impaired immune function. • Hair loss, eye and skin lesions. • Altered taste, loss of appetite, and delayed wound healing.

24. Zinc • Zinc Toxicity • UL for Adults: 40 mg/day. • Symptoms • Loss of appetite. • Impaired immunity. • Low HDL. • Copper and iron deficiencies. • Vomiting and diarrhea. • Exhaustion. • Headaches. • Zinc Recommendations and Sources • RDA Men: 11 mg/day. • RDA Women: 8 mg/day.

25. Zinc • Zinc in foods • Protein-containing foods such as shellfish, meats, poultry, milk, and cheese. • Whole grains, legumes, and some fortified cereals. • Zinc Supplementation • Developing countries use zinc to reduce incidence of death associated with diarrhea. • Zinc lozenges for the common cold are controversial and inconclusive.

26. Iodine • GI tract converts iodine to iodide • Iodine – in food • Iodide – in body • Roles in the body • Part of thyroid hormones • Body temperature, metabolic rate, reproduction, growth, blood cell production, nerve and muscle function, etc.

27. Iodine • Deficiency • Thyroid hormone production declines • Greater secretion of thyroid-stimulating hormone (TSH) • Goiter • Enlarged thyroid • Most common cause of preventable mental retardation and brain damage • Cretinism-severe def during pregnancy; irreversible

28. Iodine • Toxicity • Interferes with thyroid function • Enlarges thyroid gland • Goiter in an infant • UL • Adult: 1100 micrograms/day • Recommendations • Sources

29. Selenium • Substitute for sulfur in some amino acids • Methionine, cysteine, and cystine • Roles in body • Antioxidant • Part of proteins • Glutathione peroxidase; works with vit E • Prevents free-rad formation • Conversion of thyroid hormone to active form

30. Selenium • Deficiency • Heart disease • Cancer • May be protective factor • Foods vs. supplements • Toxicity • UL: 400micrograms/day • Effects

31. Selenium • Sources • Found in soil • Meats, milk, and eggs • Brazil nuts • Recommendations • RDA: 55µg/day

32. Copper • Transport and balance depend on a system of proteins • Roles in body • Constituent of enzymes • Reactions that consume oxygen or oxygen radicals • Iron metabolism • Defense against oxidative damage • Other roles

33. Copper • Deficiency • Deficiency is rare in the U.S.; however, symptoms include anemia and bone abnormalities. • In Menkes disease, copper cannot be released into the circulation. • Recommendations – Adults: 900 g/day. • Sources • Seafood, nuts, seeds, and legumes. • Whole grains. • In houses with copper plumbing, water can be a source. • Toxicity • Excessive intakes • Foods vs. supplements • Genetic disorders • Menkes disease • Wilson’s disease • Major route of elimination appears to be bile

34. Manganese • Body locations • Bones • Metabolically active organs • Roles in body • Cofactor for enzymes that facilitate metabolism • Bone formation • Conversion of pyruvate to a TCA cycle compound

35. Manganese • Deficiency • Deficiency symptoms are rare. • Phytates, calcium, and iron limit absorption. • Toxicity • Toxicity occurs with environmental contamination. • UL for Adults: 11 mg/day. • Toxicity symptoms include nervous system disorders. • Manganese Recommendations and Sources • Recommendations • AI Men: 2.3 mg/day. • AI Women: 1.8 mg/day. • Sources include nuts, whole grains, leafy vegetables, and tea.

36. Fluoride • Roles in the Body • Formation of teeth and bones. • Helps to make teeth resistant to decay. • Fluorapatiteis the stabilized form of bone and tooth crystals. • Fluoride and dental caries • Widespread health problem. • Leads to nutritional problems due to issues with chewing. • Toxicity • Tooth damage called fluorosis – irreversible pitting and discoloration of the teeth. • UL for Adults: 10 mg/day.

37. Fluoride • Prevention of fluorosis • Monitor fluoride content of local water supply. • Supervise toddlers during tooth brushing. • Watch quantity of toothpaste used (pea size) for toddlers. • Use fluoride supplements only if prescribed by a physician. • Recommendations • AI Men: 4 mg/day. • AI Women: 3 mg/day. • Sources include fluoridated drinking water, seafood, and tea.

38. Chromium • Roles in the body • Participates in carbohydrate and lipid metabolism • Helps maintain glucose homeostasis • Diabetes-like condition • Sources • Refined foods • Supplements

39. Chromium • Roles in the Body • Enhances insulin action and may improve glucose tolerance. • Low chromium levels can result in elevated blood sugar levels. • Glucose tolerance factors (GTF) are small organic compounds that enhance insulin’s action and some contain chromium. • Recommendations • AI Men: 35 g/day. • AI Women: 25 g/day. • Sources include meat (especially liver), whole grains, and Brewer’s yeast. • Supplements • Claims about reducing body fat and improving muscle strength remain controversial.

40. Closing Thoughts on the Nutrients • Look at nutrients as a whole • Work cooperatively with one another • Actions are most often interactions • Most foods deliver multiple nutrients • Needs are based on the support of optimal health • Nutrients are being examined in context of whole diet