Whitney & Rolfes – Understanding Nutrition, 12 th Edition The Trace Minerals Chapter 13

Whitney & Rolfes – Understanding Nutrition, 12 th Edition 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

Whitney & Rolfes – Understanding Nutrition, 12 th Edition The Trace Minerals – An Overview  Interactions  Common and well coordinated  May lead to nutrient imbalances  Cause a deficiency  Interfere with work of minerals  Contaminant minerals causing toxic reactions

Whitney & Rolfes – Understanding Nutrition, 12 th Edition Iron  Too little and too much can be harmful  Roles in the body  Switches back and forth between two forms  Ferrous iron  Ferric iron  Cofactor in oxidation-reduction reactions  Part of electron carriers  Hemoglobin and myoglobin

Whitney & Rolfes – Understanding Nutrition, 12 th Edition Iron  Absorption  Body conserves iron  Balance maintained primarily through absorption  Ferritin  Iron-storage in small intestine  Transferrin  Iron transport protein

Whitney & Rolfes – Understanding Nutrition, 12 th Edition Iron Absorption

If the body does not need iron Iron is not absorbed and is excreted in shed intestinal cells instead. Thus, iron absorption is reduced when the body does not need iron. If the body needs iron Stepped Art 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. Fig. 13-2, p. 426

Whitney & Rolfes – Understanding Nutrition, 12 th Edition Iron  Absorption  Dietary sources  Heme iron  Nonheme iron  Absorption-enhancing factors  MFP  Vitamin C  Some acids and sugars

Whitney & Rolfes – Understanding Nutrition, 12 th Edition Heme and Nonheme Iron in Foods

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%). Only foods derived from animal flesh provide heme, but they also contain nonheme iron. All of the iron in foods derived from plants is nonheme iron. Key: Heme Nonheme Stepped Art Fig. 13-3, p. 426

Whitney & Rolfes – Understanding Nutrition, 12 th Edition Iron  Absorption-inhibiting factors  Phytates  Vegetable proteins  Calcium  Polyphenols  Dietary factors combined  Individual variation in absorption  Health, stage in life cycle, and iron status

Whitney & Rolfes – Understanding Nutrition, 12 th Edition Iron  Transport  Transferrin  Storage  Ferritin  Hemosiderin  Recycling  Balance  Hepcidin

Some iron delivered to myoglobin of muscle cells Some losses if bleeding occurs Iron-containing hemoglobin in red blood cells carries oxygen. Transferrin carries iron in blood. Some losses via sweat, skin, and urine Stepped Art 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). Fig. 13-4, p. 428

Whitney & Rolfes – Understanding Nutrition, 12 th Edition Iron  Deficiency  Most common nutrient deficiency worldwide  Populations affected in U.S.  Link with being overweight  Vulnerable stages in life  Women in reproductive years  Pregnancy  Infants and young children  Adolescence

Whitney & Rolfes – Understanding Nutrition, 12 th Edition 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

Whitney & Rolfes – Understanding Nutrition, 12 th Edition Iron  Iron deficiency and anemia  Deficiency – depleted iron stores without regard to degree of depletion  Anemia – severe depletion of iron stores  Low hemoglobin concentrations  Results

Whitney & Rolfes – Understanding Nutrition, 12 th Edition Normal and Anemic Blood Cells

Whitney & Rolfes – Understanding Nutrition, 12 th Edition 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

Whitney & Rolfes – Understanding Nutrition, 12 th Edition Iron  Toxicity  Hereditary hemochromatosis  Most common genetic disorder in U.S.  Hemosiderosis  Signs and symptoms  Transferrin saturation & serum ferritin  Characteristics of condition  Treatment

Whitney & Rolfes – Understanding Nutrition, 12 th Edition Iron  Heart disease  Excess iron  Free radicals  Cancer  Free-radical damage  Iron poisoning  Symptoms of toxicity  UL

Whitney & Rolfes – Understanding Nutrition, 12 th Edition Iron  Recommendations and sources  Select iron-rich foods  Natural – meats, fish, poultry, legumes, eggs  Enriched – flour and grain products  RDAs  Vegetarians  Women  Maximizing absorption

Whitney & Rolfes – Understanding Nutrition, 12 th Edition Iron in Selected Foods

Whitney & Rolfes – Understanding Nutrition, 12 th Edition Iron  Contamination & supplementation  Iron cookware  Iron content of foods  Supplements  Groups that may need supplements  Enhancing absorption  Vitamin C  Physician prescription

Whitney & Rolfes – Understanding Nutrition, 12 th Edition 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

Whitney & Rolfes – Understanding Nutrition, 12 th Edition Zinc  Absorption  Rate varies depending on zinc status  Dietary factors  Recycling  Small intestine  Two doses of zinc  Enteropancreatic circulation  Zinc losses

Whitney & Rolfes – Understanding Nutrition, 12 th Edition Enteropancreatic Circulation of Zinc

If the body needs zinc If the body does not need zinc Mucosal cells in the intestine store excess zinc in metallothionein. Zinc is not absorbed and is excreted in shed intestinal cells instead. Thus, zinc absorption is reduced when the body does not need zinc. Metallothionein releases zinc to albumin and transferrin for transport to the rest of the body. Zinc in food The pancreas uses zinc to make digestive enzymes and secretes them into the intestine. Stepped Art Fig. 13-7, p. 435

Whitney & Rolfes – Understanding Nutrition, 12 th Edition Zinc  Transport  In the blood  Albumin  Transferrin  Iron and zinc interactions  Zinc and copper interactions

Whitney & Rolfes – Understanding Nutrition, 12 th Edition Zinc  Deficiency  Vulnerable groups  Rich sources of zinc  Dietary components that inhibit zinc absorption  Effects of zinc deficiency  Growth retardation  Impaired immune response  Damage to central nervous system

Whitney & Rolfes – Understanding Nutrition, 12 th Edition Zinc  Toxicity  Symptoms  Interference with copper metabolism  Sources  Protein-rich foods  Recommendations  Supplementation  Treatment of childhood infections

Whitney & Rolfes – Understanding Nutrition, 12 th Edition Zinc in Selected Foods

Whitney & Rolfes – Understanding Nutrition, 12 th Edition 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.

Whitney & Rolfes – Understanding Nutrition, 12 th Edition Iodine  Deficiency  Thyroid hormone production declines  Greater secretion of thyroid-stimulating hormone (TSH)  Goiter  Most common cause of preventable mental retardation and brain damage  Cretinism  Iodized salt

Whitney & Rolfes – Understanding Nutrition, 12 th Edition Iodine  Toxicity  Interferes with thyroid function  Enlarges thyroid gland  Goiter in an infant  UL  Recommendations  Sources  Processed foods

Whitney & Rolfes – Understanding Nutrition, 12 th Edition Selenium  Substitute for sulfur in some amino acids  Methionine, cysteine, and cystine  Roles in body  Antioxidant  Part of proteins  Glutathione peroxidase  Conversion of thyroid hormone to active form

Whitney & Rolfes – Understanding Nutrition, 12 th Edition Selenium  Deficiency  Heart disease  Cancer  May be protective factor  Foods vs. supplements  Toxicity  UL  Effects

Whitney & Rolfes – Understanding Nutrition, 12 th Edition Selenium  Sources  Found in soil  Meats, milk, and eggs  Brazil nuts  Recommendations  RDA  Based on glutathione peroxidase activity

Whitney & Rolfes – Understanding Nutrition, 12 th Edition 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

Whitney & Rolfes – Understanding Nutrition, 12 th Edition Copper  Deficiency  Cardiovascular disease  Toxicity  Excessive intakes  Foods vs. supplements  Genetic disorders  Menkes disease  Wilson’s disease

Whitney & Rolfes – Understanding Nutrition, 12 th Edition Copper  Sources  Legumes, whole grains, nuts, shellfish, seeds  Copper plumbing  More than half of copper from foods is absorbed  Route of elimination  Bile

Whitney & Rolfes – Understanding Nutrition, 12 th Edition 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

Whitney & Rolfes – Understanding Nutrition, 12 th Edition Manganese  Deficiency  Requirements are low  Factors limiting manganese absorption  Toxicity  Environmental contaminate  UL  Recommendations and sources  Grain products

Whitney & Rolfes – Understanding Nutrition, 12 th Edition Fluoride  Found in bones & teeth  Fluorapatite  Dental decay  Sources  Drinking water  Tea and fish  Toxicity  Fluorosis

Whitney & Rolfes – Understanding Nutrition, 12 th Edition Chromium  Roles in the body  Participates in carbohydrate and lipid metabolism  Helps maintain glucose homeostasis  Diabetes-like condition  Sources  Refined foods  Supplements

Whitney & Rolfes – Understanding Nutrition, 12 th Edition Molybdenum  Working part of several metalloenzymes  Dietary deficiencies are unknown  Sources  Legumes, breads, grain products, leafy green vegetables, milk, and liver  Toxicity is rare  UL  Characteristics

Whitney & Rolfes – Understanding Nutrition, 12 th Edition Other Trace Minerals  Research is difficult  Small quantities  Human deficiencies are unknown  Nickel  Silicon  Vanadium  Cobalt  Boron

Whitney & Rolfes – Understanding Nutrition, 12 th Edition Contaminant Minerals  Impair body’s growth, work capacity, and general health  Heavy metals  Lead  Indestructible  Displaces other minerals  Mercury  Cadmium

Whitney & Rolfes – Understanding Nutrition, 12 th Edition 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

Whitney & Rolfes – Understanding Nutrition, 12 th Edition Highlight 13 Phytochemicals and Functional Foods

Whitney & Rolfes – Understanding Nutrition, 12 th Edition Phytochemicals  Found in plant-derived foods  Have biological activity in the body  Physiological effects  Suppression of diseases  Adverse effects if consumed in excess

Whitney & Rolfes – Understanding Nutrition, 12 th Edition Phytochemicals  Defending against cancer  Protect against DNA damage  Soybeans  Phytoestrogens  Tomatoes  Lycopene

Whitney & Rolfes – Understanding Nutrition, 12 th Edition Phytochemicals  Defending against heart disease  Flavonoids  Food sources  Heart-protection factors  Carotenoids  Phytosterols  Lignans

Whitney & Rolfes – Understanding Nutrition, 12 th Edition Phytochemicals

Phytochemicals

Functional Foods  All foods that have a potentially beneficial effect on health  Whole  Fortified  Modified  Characteristics similar to food and drugs  Consumption patterns for beneficial effect  Cost

Whitney & Rolfes – Understanding Nutrition, 12 th Edition Unanswered Questions  Research for safety and effectiveness is still in progress  Questions  Does it work?  How much does it contain?  Is it safe?  Is it healthy?