The Trace Minerals

Trace Minerals n Iron, Zinc, Iodine, Selenium, Copper, Manganese, Fluoride, Chromium, Molybdenum n Needed in minute quantities n Toxicity may occur at intakes not far above estimated requirement n Found in a variety of foods

Iron n General information u Most of the body’s iron is in hemoglobin and myoglobin u Carries oxygen for use in energy metabolism u Proteins assist with iron absorption, transport, and storage

Iron - RDA n Men u 8 mg/day n Women u 18 mg/day (19-50 yrs); 8 mg/d (51 +) u Upper Level: Adults: 45 mg/day

Iron - Major Functions n Carries oxygen n Co-factor to enzymes involved in oxidation- reduction reactions n Part of electron carriers in electron transport chain

Slide 6 Figure 13-3 Page 441 Iron Recycled in the Body Iron-containing hemoglobin in red blood cells carries oxygen. Transferrin carries iron in blood. Some iron delivered to myoglobin of muscle cells Some losses if bleeding occurs Bone marrow incorporates iron into hemoglobin of red blood cells and stores excess iron in ferritin (and hemosiderin). Liver (and spleen) dismantles red blood cells, packages iron into transferrin, and stores excess iron in ferritin (and hemosiderin). Some losses via sweat, skin, and urine

Iron - Deficiency n Worldwide, most common nutrient deficiency, affects > 1 billion people n High risk: women in reproductive years, pregnant women, infants & young children, teenagers n Blood loss may also lead to iron deficiency n Develops in stages n Iron-deficiency anemia  severe depletion iron stores

Slide 8 Figure 13-4 Page 443 Normal and Anemic Blood Cells Blood cells in iron-deficiency anemia are small (microcytic) and pale (hypochromic) because they contain less hemoglobin. Both size and color are normal in these blood cells.

Slide 9 Table 13-1 Page 458

Iron - Toxicity n Toxicity from excess iron results in iron overload n More common in men n Iron-containing supplements leading cause of accidental poisoning in children

Major Food Sources n Red meats, fish, poultry sources of heme iron & contain MFP factor, which enhance iron absorption; shellfish, eggs n Non-heme sources of iron include legumes, iron-enriched grains n Non-heme iron absorption increased with MFP foods, Vitamin C

Slide 12 Figure 13-2 Page 440 Heme and Nonheme Iron in Foods All the iron in foods derived from plants is nonheme iron. Only foods derived from animal flesh provide heme, but they also contain nonheme iron. Heme accounts for about 10% of the average daily iron intake, but it is well absorbed (about 25%). Nonheme iron accounts for the remaining 90% but it is less well absorbed (about 17%). Heme Key: Nonheme

Slide 13 In-text Figure Page 445 When the label on a grain product says “enriched,” It means iron and several B vitamins have been added.

Slide 14 In-text Figure Page 447 An old-fashioned iron skillet adds iron to foods.

Zinc n General information u Required as a cofactor by more than 100 enzymes; all cells contain zinc n RDA – Men: 11 mg/d; Women: 8 mg/d n Upper level: Adults - 40 mg/d

Zinc - Major Functions n Part of many enzymes n Involved in making genetic material and proteins n Involved in immune reactions n Transport of Vitamin A n Taste perception

Zinc - Deficiency n Severe growth retardation n Hinders digestion & absorption, causing diarrhea n Impairs immune function n Alters taste, causes anorexia, slows wound healing

Slide 18 Figure 13-7 Page 449 Zinc-Deficiency Symptoms—The Stunted Growth of Dwarfism The boy on the left is 17 years old but is only 4 feet tall. The man on the right is an adult of average height.

Zinc - Toxicity n Vomiting, diarrhea, headaches, other symptoms

Zinc-Food Sources n Protein-containing foods: meats, fish, poultry, whole grains, vegetables

Slide 21 In-text Figure Page 449 Zinc is highest in protein-rich foods such as oysters, beef, poultry, legumes, and nuts.

Iodine n General information u Part of thyroid hormone that regulates body temperature, metabolic rate, reproduction, growth, and more n RDA u Adults: 150 µg/day u Upper level: 1.1 mg/day

Iodine - Deficiency n Simple goiter; cretinism n Enlargement of thyroid gland, weight gain

Iodine - Toxicity n Enlargement of thyroid gland n Especially damaging to developing fetus n Upper limit: 1000 µg/day

Iodine - Food Sources n Ocean is world’s major source of iodine n Iodized salt, seafood, bread, dairy products, plants grown in iodine-rich soil

Slide 26 In-text Figure Page 452 Only “iodized salt” has had iodine added.

Selenium, Copper, Manganese n Selenium – Antioxidant, works with Vitamin E; deficiency associated with a heart disease; food sources – seafood, meat, whole grains n Copper – Part of several enzymes, necessary for absorption & use of iron; deficiency is rare; food sources – legumes, whole grains, nuts, shellfish n Manganese – Involved in various metabolic processes; deficiencies rare; food sources – nuts, whole grains, leafy veggies

Fluoride n Major Functions: Makes bones stronger, teeth resistant to decay n Food Sources: Fluoridated water, tea, foods prepared with fluoridated water, seafood n Toxicity: Fluorosis (mottling of teeth)

Slide 29 Figure Page 456 U.S. Population with Access to Fluoridated Water through Public Water Systems Key: < 49% 50% – 74% > 75%

Chromium, Molybdenum n Chromium – Participates in carbohydrate and lipid metabolism; present in a variety of foods n Molybdenum – Cofactor for several enzymes; unknown deficiency; found in legumes, cereals, organ meats

Slide 31 Figure 13-1 Page 439 Iron Absorption If the body needs iron Iron is excreted in shed intestinal cells. If the body does not need iron Mucosal cells in the intestine store excess iron in mucosal ferritin (a storage protein). Iron in food Mucosal ferritin releases iron to mucosal transferrin (a transport protein), which hands off iron to another transferrin that travels through the blood to the rest of the body.

Slide 32 In-text Figure Page 441 This chili dinner provides several factors that may enhance iron absorption: heme and non-heme iron and MFP from meat, nonheme iron from legumes, and vitamin C from tomatoes.

Slide 33 Figure 13-5 Page 446 Iron in Selected Foods Key: Fruits Milk and milk products Legumes, nuts, seeds Meats Best sources per kcalorie Breads and cereals Vegetables IRON Meats (red), legumes (brown), and some vegetables (green) make the greatest contributions of iron to the diet. RDA for women 51+ RDA for women 19–50 RDA for men

Slide 34 Figure 13-6 Page 448 Enteropancreatic Circulation of Zinc If the body needs zinc Zinc in food The pancreas uses zinc to make digestive enzymes and secretes them into the intestine. Zinc is excreted in shed intestinal cells. Metallothionein releases zinc to albumin and transferrin for transport to the rest of the body. If the body does not need zinc Mucosal cells in the intestine store excess zinc in metallothionein.

Slide 35 Figure 13-8 Page 450 Zinc in Selected Foods Label Key: Fruits Milk and milk products Legumes, nuts, seeds Meats Best sources per kcalorie Breads and cereals Vegetables ZINC Meat, fish, and poultry (red) are concentrated sources of zinc. Milk (white) and legumes (brown) contain some zinc. RDA for women RDA for men Micrograms RAE Food Serving size (kcalories)

Slide 36 Figure Page 458 Cobalt with Vitamin B 12 The intricate vitamin B 12 molecule contains one atom of the mineral cobalt. The alternative name for vitamin B 12, cobalamin, reflects the presence of cobalt in its structure.

Slide 37 Click to view animation. Practice planning meals with varying energy needs to meet recommended intakes of several minerals. Animation

Slide 38 In-text Figure Page 465 Phytochemicals and Functional Foods

Slide 39 Table H13-1 Page 466

Slide 40 Table H13-1(2) Page 466 (cont.)

Slide 41 In-text Figure Page 467 Nature offers a variety of functional foods that provide us with many health benefits.

Slide 42 Fig. H13-1 (1) Page 468 An Array of Phytochemicals in a Variety of Fruits and Vegetables The phytochemical resveratrol found in grapes (and nuts) protects against cancer by inhibiting cell growth and against heart disease by limiting clot formation and inflammation. The flavonoids in cocoa and chocolate defend against oxidation and reduce the tendency of blood to clot. Broccoli and broccoli sprouts contain an abundance of the cancer-fighting phytochemical sulforaphane.

Slide 43 Fig. H13-1 (2) Page 468 An Array of Phytochemicals in a Variety of Fruits and Vegetables (cont’d) Tomatoes, with their abundant lycopene, may defend against cancer by protecting DNA from oxidative damage. The ellagic acid of strawberries may inhibit certain types of cancer. An apple a day—rich in flavonoids—may protect against lung cancer. Spinach and other colorful vegetables contain the carotenoids lutein and zeaxanthin, which help protect the eyes against macular degeneration.

Slide 44 Fig. H13-1 (3) Page 468 An Array of Phytochemicals in a Variety of Fruits and Vegetables (cont’d) The monoterpenes of citrus fruits (and cherries) may inhibit cancer growth. Flaxseed, the richest source of lignans, may prevent the spread of cancer. The phytoestrogens of soybeans seem to starve cancer cells and inhibit tumor growth; the phytosterols may lower blood cholesterol and protect cardiac arteries.

Slide 45 Fig. H13-1 (4) Page 468 An Array of Phytochemicals in a Variety of Fruits and Vegetables (cont’d) The flavonoids in black tea may protect against heart disease, whereas those in green tea may defend against cancer. Blueberries, a rich source of flavonoids, improve memory in animals. Garlic, with its abundant organosulfur compounds, may lower blood cholesterol and protect against stomach cancer.

Slide 46 In-text Figure Page 469 Functional foods currently on the market promise to “enhance mood,” “promote relaxation and good karma,” “increase alertness,” and “improve memory,” among other claims.