Iron Absorption and Sources
28 Questions
2 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What are the two forms of iron found in food?

  • Iron sulfate and iron chloride
  • Heme iron and nonheme iron (correct)
  • Ferrous iron and ferric iron
  • Iron oxide and iron sulfide

    • Heme iron is more easily absorbed by the body than nonheme iron.

    True

    Which of the following factors enhance nonheme iron absorption?

  • Vitamin C (correct)
  • Phytates
  • Calcium
  • Oxalates

    • What is the name of the protein that carries iron in the blood?

    <p>Transferrin</p> Signup and view all the answers

    The storage protein for iron in the body is called ______.

    <p>ferritin</p> Signup and view all the answers

    What is the name of the genetic disorder that enhances iron absorption and can lead to iron overload?

    <p>Hemochromatosis</p> Signup and view all the answers

    Iron deficiency can lead to anemia.

    <p>True</p> Signup and view all the answers

    What is the RDA for iron for adult men?

    <p>8 mg/day</p> Signup and view all the answers

    Which of the following is a symptom of iron deficiency?

    <p>Fatigue</p> Signup and view all the answers

    What is the name of the trace mineral that is essential for the formation of hemoglobin?

    <p>Zinc</p> Signup and view all the answers

    Zinc is a key component of metalloenzymes.

    <p>True</p> Signup and view all the answers

    What are some of the symptoms of zinc deficiency?

    <p>Growth retardation</p> Signup and view all the answers

    What is the RDA for zinc for adult women?

    <p>8 mg/day</p> Signup and view all the answers

    Iodine is a component of thyroid hormones.

    <p>True</p> Signup and view all the answers

    The enlargement of the thyroid gland caused by iodine deficiency is called ______.

    <p>goiter</p> Signup and view all the answers

    What is the RDA for iodine for adults?

    <p>150 µg/day</p> Signup and view all the answers

    Copper is a component of several enzymes.

    <p>True</p> Signup and view all the answers

    Which of the following is a symptom of copper deficiency?

    <p>Anemia</p> Signup and view all the answers

    What is the name of the genetic disorder that causes copper buildup in the body?

    <p>Wilson's disease</p> Signup and view all the answers

    Fluoride is essential for the formation of teeth and bones.

    <p>True</p> Signup and view all the answers

    What is the name of the condition caused by excessive fluoride intake?

    <p>Fluorosis</p> Signup and view all the answers

    Chromium enhances insulin action.

    <p>True</p> Signup and view all the answers

    What are the small organic compounds that enhance insulin's action called?

    <p>Glucose tolerance factors (GTF)</p> Signup and view all the answers

    Which of the following are sources of chromium?

    <p>Whole grains</p> Signup and view all the answers

    What are some examples of heavy metals?

    <p>Lead</p> Signup and view all the answers

    Heavy metals can enter the food supply through soil, water, and air pollution.

    <p>True</p> Signup and view all the answers

    What are some of the symptoms of lead toxicity in children?

    <p>Learning disabilities, low IQ, behavior problems, slow growth, iron-deficiency anemia, sleep disturbances, nervous system disorders, slow reaction time, poor coordination, impaired hearing.</p> Signup and view all the answers

    Lead toxicity can lead to kidney failure in adults.

    <p>True</p> Signup and view all the answers

    Study Notes

    Iron

    • Iron exists in two forms in food: heme iron (animal source) and nonheme iron (animal and plant sources)
    • Heme iron has high bioavailability and isn't affected by dietary factors
    • Factors that enhance nonheme iron absorption include MFP factor, Vitamin C, citric acid, lactic acid, HCl from stomach, and sugars
    • Factors that inhibit nonheme iron absorption include phytates, fibers, oxalates, calcium and phosphorus in milk, tannic acid, and EDTA
    • Heme iron accounts for about 10% of daily iron intake and is well absorbed (about 25%)
    • Nonheme iron accounts for the remaining 90% but is less well absorbed (about 17%)
    • All iron in plant-derived foods is nonheme iron
    • Iron absorption is regulated by mucosal cells in the intestine
    • If the body needs iron, mucosal ferritin releases iron to mucosal transferrin which hands off iron to another transferrin to travel in the blood to the rest of the body
    • If the body doesn't need iron, it's excreted in shed intestinal cells

    Iron Absorption, Transport, & Recycling

    • Some iron loss occurs via sweat, skin, and urine
    • Transferrin carries iron in the blood
    • Liver and spleen dismantle red blood cells, package iron into transferrin, and store excess iron in ferritin and hemosiderin
    • Bone marrow incorporates iron into hemoglobin of red blood cells and stores excess iron in ferritin and hemosiderin
    • Iron-containing hemoglobin in red blood cells carries oxygen
    • Some iron is delivered to myoglobin in muscle cells
    • Some iron is lost if bleeding occurs

    Iron Deficiency and Anemia

    • Iron deficiency is depleted iron stores
    • Iron-deficiency anemia is a severe depletion of iron stores, also called microcytic hypochromic anemia
    • Symptoms of iron deficiency include fatigue, weakness, headaches, apathy, pallor, and poor resistance to cold temperatures
    • Iron deficiency impairs energy metabolism, neurotransmitter synthesis, physical work capacity, and mental productivity
    • Pica (eating non-food substances) is a characteristic behavior of iron deficiency, and common in women and children from low-income groups

    Iron Toxicity (Iron Overload)

    • Known as hemochromatosis, often caused by a genetic disorder enhancing iron absorption
    • Repeated blood transfusions and massive supplemental iron doses can also lead to iron overload
    • Iron overload may cause hemosiderosis
    • Symptoms of iron overload include apathy, lethargy, and fatigue

    Zinc

    • Zinc supports the work of metalloenzymes
    • It's involved in DNA and RNA production, heme and hemoglobin synthesis, essential fatty acid metabolism, Vitamin A release from liver stores, and carbohydrate metabolism
    • Zinc synthesizes proteins, affects platelets in blood clotting and wound healing, affects thyroid hormone function, influences behavior, learning performance, and taste perception
    • Zinc is crucial in sperm development and fetal development
    • Zinc absorption depends on the Zinc status in the body and phyates and fiber can reduce Zinc absorption

    Zinc Deficiency and Toxicity

    • Significant sources: protein-containing foods, red meats, shellfish, and whole grains
    • RDA for Zinc: Men - 11 mg/day and Women - 8 mg/day
    • Deficiency symptoms: growth retardation, delayed sexual maturation, impaired immune function, hair loss, eye and skin lesions, loss of appetite
    • Toxicity symptoms: loss of appetite, impaired immunity, and copper and iron deficiencies

    Iodine

    • Iodine is a component of two thyroid hormones
    • Iodine regulates growth, development, and metabolic rate
    • Iodine deficiency leads to simple goiter (enlargement of the thyroid gland)
    • Goiter can also result from malfunction of the thyroid, and from overconsumption of goitrogens
    • Cretinism is a congenital disease, commonly caused by maternal iodine deficiency during pregnancy
    • Iodine toxicity symptoms include underactive thyroid gland and goiter

    RDA for Iodine

    • RDA for adults: 150 µg/day
    • Sources: iodized salt, seafood, bread and dairy products, plants grown in iodine-rich soils, and animals that feed on such plants

    Copper

    • Copper is a component of many enzymes, and some containing copper are antioxidants
    • Copper deficiency can cause anemia and bone abnormalities, including Menkes disease
    • Copper toxicity includes Wilson's disease
    • RDA for copper in adults is 900 µg/day
    • Sources include seafood, nuts, seeds, legumes, and whole grains

    Other Trace minerals (Fluoride and Chromium)

    • Fluoride - Roles: Formation of teeth and bones, helps make teeth resistant to decay - Deficiency: Tooth decay - Toxicity: Tooth damage (fluorosis) - RDA: Men: 4 mg/day, Women: 3 mg/day - Sources: Fluoridated water, seafood, tea
    • Chromium - Roles: Enhances insulin action (through Glucose Tolerance Factors), involved in carbohydrate metabolism - RDA: Men: 35 µg/day, Women: 25 µg/day - Sources : Meat, liver, whole grains, brewer's yeast

    Contaminant Minerals (Heavy Metals)

    • Contaminant minerals (heavy metals) include mercury, lead, and cadmium
    • These enter the food chain through soil, water, and air pollution
    • They disrupt body processes and impair nutrition status
    • Lead toxicity in children can cause learning disabilities, low IQ, behavior problems, slow growth, iron-deficiency anemia, dental caries, sleep disturbances, nervous system disorders, seizures, slow reaction time, and poor coordination, impaired hearing
    • Lead toxicity in adults can cause hypertension and reproductive complications, and kidney failure

    Studying That Suits You

    Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

    Quiz Team

    Related Documents

    Trace Minerals PDF

    Description

    This quiz covers the essential aspects of iron, including its two forms: heme and nonheme iron. You'll learn about their absorption rates, factors affecting bioavailability, and the role of the body in regulating iron levels. Test your knowledge on dietary sources of iron and their impact on health.

    More Like This

    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser