Nutrition chapter 13- Trace minerals

Molybdenum

Acts as working part of many metalloenzymes; dietary deficiency unknown b/c amounts needed are so low; sources: legumes, breads, grain products, leafy green veges, milk, liver; toxicity: rare; but UL established ; toxicity results in kidney damage, reproductive abnormalities

Interactions between trace minerals

Are common and well coordinated to meet body's needs; interactions may lead to nutrient imbalances- excess of one causing deficiency in another; deficiency may allow contaminant mineral to cause a toxic reaction

Iron absorption

Body conserves iron- hard to excrete so balance maintained through absorption- more absorbed when stores are empty, less when stores are full; Ferritin: iron storage protein- captures iron from foods, stores in sm. intestine; Transferrin: when body needs iron- ferritin releases some to this transport protein

Maximize absorption of Iron

By incorporating iron-rich foods into diet that is low of inhibitors (foods like leavened breads, fermented soy products) and high in enhancers (foods rich in vitamin C and organic acids) Iron added to food is nonheme, but when eaten with absorption-enhancing foods, enrichment iron can increase iron stores and reduce iron deficiency. Maximize absorpt of nonheme iron: eat meat for MFP factor, fruits and veges for vit C. Iron of bread will be enhanced by the Vitamin C in slice of tomato on sandwhich.

Zinc transport

By protein albumin; some also bind to transferrin

Selenium Functions

Can be used as substitute for sulfur in amino acid methionine, cysteine, cysteine; Roles as an antioxidant: works as part of proteins (glutathionine peroxidase); conversion of TH to active form.

Goiter

Caused by too much or too little iodine

Chromium Supplementation

Claims that helps lose fat and build muscle isn't true

Pica

Craving and consumption of non food substances such as chalk, starch, dirt, ice

Wilson's disease

Cu accumulates in liver and brain, creating toxicity (we can manage this with Zn supp and limiting Cu food sources)

Defending against other diseases

Curcumin (in curry powder) may reverse insulin resistance, inflammation, other obesity related symptoms; lutein and zeaxanthin (carotenoids) may protect eyes and skin from UV damage and bone from mineral losses

Hypothyroidism

Decreased metabolic rate, weight gain, not enough TH

Balance of Iron

Depends on careful regulation of absorpt, transport, storage, recycling, losses- hepcidin is a hormone central to regulation of iron balance- produced by liver and limits absorption from small intest and controls release from liver, spleen, bone marrow

Iron absorption factors

Depends on dietary source: heme iron found in foods from animals: only 40% of iron in meat is in heme form, 60% in nonheme form; nonheme form found in 100% in plant-based foods

Anemia

Depleted iron stores without regard to degree of depletion- anemia is severe depletion of iron stores results in low hemoglobin concentration; cells can't carry enough O2- fatigue, weakness, headaches, apathy, pallor, poor resistance to cold temperatures.

Assessment of iron deficiency

Develops in stages 1. Iron stores diminish- measure serum ferritin in blood 2. Decrease in transport iron: transferrin increases to adapt to enhance absorpt- more transferrin and less iron in blood, more advanced deficiency 3. Lack of iron limits hemoglobin production, hematocrit values decline

Iron deficiency and behavior

Energy metabolism impaired, neurotransmitter synthesis is altered- reduces physical work capacity and mental productivity, causes motivational problems

Heavy metals

Enter food supply through soil, water, air pollution: lead, mercury, Cadmium

Menkes disease

Error in transport of Cu; intestinal cells absorb Cu but can't release it into circulation causing deficiency

Cu toxicity

Excessive intakes from foods unlikely; excess from supplements may cause liver damage so UL set.

Fluoride Functions

Found in bones and teeth; fluorapatite: the stabilized form of bone and tooth crystal, in which fluoride has replaced the hydroxyl group of hydroxyapatite; w/o fluoride, dental decay is common

Sources/ recommendation of Selenium

Found in soil- crops that we consume; meats, milks, eggs, brazil nuts; Recomm: RDA based on amount needed to maximize glutathionine peroxidase activity

Iron contamination

From nonfood sources: water supply from well water, iron cookware (good for women, not so much for males)

Manganese Recc and Sources

Grain products; AI set

Effects of Zn Deficiency

Growth retardation, impaired immune response, damage to central nervous system, causes diarrhea which worsens malnutrition for other nutrients as well, since Zn deficiency directly impairs vitamin A metabolism, vitamin A deficiency sympts often appear

Enhancing absorption of nonheme iron

Heme is not influenced by dietary factors: MFP factor in meat, fish, poultry: promotes absorption of nonheme iron from other foods eaten at same meal; Vit C enhances absorpt by capturing it and keeping it in ferrous form; some acids and sugars also enhance nonheme absorpt.

Contaminant minerals

Impair body's growth, work capacity, general health

Iodine Functions

In GI tract, iodine converted to iodide (get iodine in food, called iodide in body); part of TH which regulates temp, metabolic rate, reproduction, growth, blood cell production, nerve and muscle fn, etc.

Iron storage

In ferritin in liver mostly or bone marrow or spleen; or in hemosiderin if iron conc. is unusually high (releases iron more slowly than ferritin which protects the body from free iron radical)

Hyperthyroidism

Increased metabolic rate, weight loss, too much TH

Iron overload

Increases risk of CV disease, cancer (cells destroyed); called hemochromatosis- caused by a genetic failure to prevent unneeded iron in the diet from being absorbed- most common genetic disorder in the US; signs and symp: similar to iron deficiency- apathy, lethargy, fatigue; treatment involves chelation therapy (uses achelate therapy to form a complex with iron and promote its excretion)

Lead

Indestructible; displaces other minerals so they can't perform their functions: increased lead intake can induce iron deficiency and iron deficiency makes lead toxicity more likely

Recomm of Zn

Intakes usually higher than recc.

Toxicity of Iodine

Interferes with Thyroid function (enlarges thyroid gland); goiter may develop in infant: UL is 1100micrograms/day in adults; recommendation is small amount

Zinc roles

Involved in over 100 different reactions in the body; metalloenzyme (enzyme that contains metal); regulation of gene expression, stabilizes cell membranes, helps in immune function, growth and development, synthesis, storage, and release of insulin, blood clotting, affects TH function, behavior and learning performance, visual pigment, taste perception, sperm production

Recycling of RBS's

Iron is salvaged in transferrin to go back to bone marrow to be reused to make new RBCs

Sources of Cu

Legumes, whole grains, nuts, shellfish, seeds; water from Cu plumbing; more than half of Cu from food is absorbed (very well absorbed)

Iron overload and heart disease

Link between heart disease and excess iron; cancer too: free-radical activity; high fiber diet- phytate will bind iron and limit its free-radical activity

Manganese Function

Located in bones, metabolically active organs like liver, kidney, pancreas; cofactor for many enzymes that facilitate metabolism of pyruvate to a TCA cycle compound

Fluoride Toxicity

May damage teeth, cause fluorosis (discoloration and pitting of tooth enamel- only occurs during tooth development--so don't swallow toothpaste or mouthwash)

Selenium deficiency

May protect against some cancers but supplementation may damage DNA, cause harm, so get through food

Toxicities in trace minerals

Most are toxic at 2.5-7 x above requirements- important not to exceed UL; FDA can't limit amounts of trace minerals in supplements- better to meet nutrient needs by selecting variety of foods

Iron deficiency

Most common nutrient deficiency worldwide: most vulnerable: women in reproductive years (menstruation), pregnancy (high demand from fetal tissue); infants and young children (increased needs for growth and not getting much in diet-lower kcal needs); obesity( correlation with decreased absorpt), bleeding from ulcer, accident, malaria, blood donors

Nonessential trace minerals

Nickel, Silicon, Vanadium, Cobalt, Boron

Manganese Toxicity

Occurs from environmental contaminated with manganese (like miners- symptoms of brain disease, abnormal appearance and behavior), UL established in intakes from food, water, supp

Chromium Roles

Participates in carb and lipid absorption; helps maintain glucose homeostasis- with low chromium, diabetes like conditions may develop with elevated blood glucose and impaired glucose tolerance, insulin response, glucagon response

Inhibiting iron absorption

Phytates in legumes and whole grains and rice, and vegetable proteins (soybeans, legumes, nuts), calcium, polyphenols (tea, coffee, grain, oregano, red wine) all bind with nonheme iron to inhibit absorption. Combined effects of enhancers and inhibitors makes it hard to estimate iron absorpt- but about 10-15% combined; Individual variation in absorpt is based on health, stage in life cycle, iron status

Phytochemicals defending against cancer

Protect against DNA damage: soybeans: protect against breast and prostate cancers- soybeans, flaxseeds, whole grains, fruits, veges rich in phytoestrogens; Tomatoes: may protect against cancer - lycopene in food, not supplement (a carotenoid) is an antioxidant that may inhibit growth of some cancer cells

Sources of Zn

Protein-rich foods

Cu deficiency

Rare; CV disease in humans

Absorption of Zinc

Rate varies depending on Zn status: Zn intake increases, rate of absorption decreases; Zn intake decreases, absorption increases (like iron); dietary factors (fiber, phytates limit absorption)

Iron supplementation

Recommended to pregnant women, infants, young children; absorption of iron as ferrous sulfate is better than other forms; absorption improves when supp. taken between meals, at bedtime on empty stomach, with liquids (not milk, tea, coffee though); no benefit in taking iron supp with orange juice because Vitamin C doesn't enhance absorption from supplement like foods; iron supplements should be taken only with prescription and must be individualized.

Manganese deficiency

Requirements are low-deficiency rare; dietary factors like phytates inhibit absorption. Also, high intakes of iron and calcium limit manganese absorption

Unanswered questions

Research for safety and effectiveness of functional foods is still in progress- does it work? how much does it contain? is it safe? healthy? be cautious and do homework!

Iron Recc and Sources

Select Iron rich foods- natural meats, fish, poultry, legumes, eggs; enriched: flour and grain products. RDAs: Women and vegetarians need more- vegetarians eat nonheme iron only and don't consume MFP protein-reduced absorption.

Recycling of Zn

Small intestine: receives 2 doses of Zn with each meal: one from food, other from Zn-rich pancreatic juices.

Cretinisn

Someone who is very short: may occur as result of severe iodine deficiency during pregnancy that causes extreme and irreversible mental and physical retardation: effort to provide iodized salt to those living in iodine-deficient areas.

Zn toxicity

Symptoms of vomiting, diarrhea, headaches, exhaustion, other sympts: UL set high because of Zn's interference with Cu metabolism

Iodine deficiency

TH production declines- greater secretion of TSH to try to get more TH- goiter may form b/c cells of Thyroid gland enlarge to trap as much iodide as they can

Supplementation of Zn

To treat childhood infections in developing countries

Zinc and Cu interactions

Too much Zn, can induce Cu deficiency

Iron and Zn interactions

Too much iron, can reduce Zn absorption (induce Zn deficiency)

Iron Functions

Too much or too little can be harmful; switches between two ionic states: ferrous iron (reduced state), ferric iron (oxidized state); so, can serve as cofactor to enzymes involved in many oxidation-reduction reactions that commonly occur in all cells; part of electron carriers for electron transport chain; found in hemoglobin in RBC's and myoglobin in muscle cells to help accept, carry, release O2.

Copper Roles

Transport and balance depend on system of proteins; constituent of enzymes, all involve reactions that consume O2 or O2 radicals, catalyze oxidation of ferrous iron to ferric iron so iron can bind to transferrin- role in iron metabolism (Cu enhances absorbance of iron, because it can switch states to make sure iron is in state it needs to be in), defense against oxidative damage of free-radicals

Selenium toxicity

UL set because high doses are toxic- causes loss/brittleness of hair and nails, garlic breath odor, nervous system abnormalities

Phytochemicals defending against heart disease

Unprocessed foods support heart health because of flavonoids (found in whole grains, legumes, soy, veges, fruits, herbs, spices, teas, chocolate, nuts, olive oil, red wine- antioxidants that help protect LDL chol against oxidation, minimize inflammation, reduce platelet stickiness, slowing progression of atherosclerosis, makes blood clots less likely) Carotenoids in fruits and veges : lutein- lowers risk of hypertension and heart disease; plant steroid of soybeans, lignans of flaxseed protect against heart disease- inhibit cholesterol absorption in body, reduce inflamm, lower BP- plant sterols reduce chol by 15%, but drugs reduce chol by 30% but are more expensive, so your choice

Chromium Sources

Unrefined foods like liver, brewer's yeast, whole grains are best- but the more refined, the less chromium is ingested

Zn Deficiency

Vulnerable groups: children (growing), middle easterns (low in meat but high in fiber and phytates which inhibit Zn abs), poor (don't buy much meat) Meat rich in Zn

Fluoride Sources

Water (not in bottled or well water), tea, fish

Functional foods

Whole, fortified, or modified foods that contain bioactive compounds that provide health benefits beyond nutrient contributions

Functional foods

all foods that have a potentially beneficial effect on health, even whole foods, fortified foods, modified; have characteristics similar to food and drugs, but don't really fit into either category; consumption patterns for beneficial effect- may need to eat functional foods several times a day for many months, even years, to have beneficial effect; fn foods like fruits and veges have no added costs, but foods that have been manufactured with phytochemicals get expensive

Iron transport

by transferrin

Deficiencies in trace minerals

can affect people of all ages, but may be difficult to recognize- children may fail to grow and thrive with deficiency

Food sources of trace minerals

depend on soil and water composition, depend on food processing

Sources of Iodine

fish is only true source, all others are fortified with iodine in some way. Fast foods (use iodine salts- but not so much now that America eats so much fast food); processed foods use regular salt now, not iodized.

Cu elimination

in bile

Antioxidants

neutralize free radicals so they can't cause symptoms

Phytochemicals

non-nutrient compound found in plants, impart color and flavor to food, may have health promoting benefits

Enteropancreatic circulation

recycling of Zn from pancreas to small intestine and back to pancreas

Phytochemical physiological effects

suppression of diseases, adverse effects if consumed in excess

Iron poisoning

symp of toxicity: GI distress, including constipation, nausea, vomiting, diarrhea- UL of 45 mg/day for adults; more symptoms: rapid heart beat, weak pulse, dizziness, shock, confusion

Zinc losses

through feces, smaller losses in urine, shed skin, hair, sweat, menstrual fluids, semen