Chapter 8 Minerals

Key Concepts The human body requires a variety of minerals to perform numerous metabolic tasks Inorganic substances Minerals = elements

Minerals Classes of minerals Major minerals (recommended intake >100 mg/day) Trace elements (<100 mg/day) Functions of minerals: Tissue building & metabolism GROWTH & MAINTENANCE What are the four fundamental elements that make up most living matter? Hydrogen, carbon, oxygen, and nitrogen Ask students to name a trace element or a major mineral. Explain that unlike carbohydrates, proteins, and fat, minerals do not require a great deal of mechanical or chemical digestion before absorption.

Major Minerals Calcium >100mg/day Phosphorus Sodium Potassium Chloride Magnesium Sulfur

Calcium Functions Bone and tooth formation Muscle contraction Nerve conduction What does the absorption of dietary calcium depend on? The food form and the interaction of three hormones that directly control absorption, along with indirect metabolic stimuli from the estrogen hormones Where can most of the body’s calcium be found? Bones and teeth Explain that calcium in the bones acts as a pool for calcium that can then be used to maintain blood calcium levels. Calcium is essential for muscle contraction.

Calcium, cont’d Requirements Deficiency states 1000 mg/day Deficiency states Osteoporosis Toxicity symptoms – kidney stones Food sources Milk is the major food source Green vegetables, fish with bones, fortified food What can reduce the risk for developing osteoporosis? Diet, especially during childhood and adolescence, physical activity including weight-bearing exercises, not smoking How many in the class drink milk or eat dairy products? Name some of the green vegetables that are good sources of calcium. Broccoli, spinach, kale

Osteoporosis Left side: normal, healthy bone Right side: osteoporotic bone Which bone looks easier to break? Figure information: Normal bone (left) versus osteoporotic bone (right). From Mahan LK, Escott-Stump S: Krause’s food & nutrition therapy, ed 12, Philadelphia, 2008, Saunders. Copyright © 2009, by Mosby, Inc. an affiliate of Elsevier, Inc. All rights reserved.

Phosphorus Functions Bone and tooth formation, works with Calcium Energy metabolism (releases energy from CHO, fat, protein) Maintain proper acid-base balance What other mineral is essential for bone and tooth formation? Calcium DNA has phosphorous in its backbone.

Phosphorus, cont’d Requirements 700 mg/day Deficiency states – rare, widely available in foods Toxicity: usually with renal disease (hyperphosphatemia) Food sources Milk, milk products, fish, eggs If a phosphorus deficiency does develop, what are the characteristics? Weakness, loss of appetite, fatigue, pain Is it difficult for most Americans to meet the requirement for phosphorus?

Sodium Functions Maintenance of water balance Acid-base balance Muscle action & transmission of nerve impulses What is the main function of sodium? Water balance Explain that sodium is needed for glucose to be absorbed.

Sodium, cont’d Requirements Deficiency – rare Toxicity Recommended 1.5 - 2.3 g/day *usual intake = 3500 mg/day Deficiency – rare strenuous exercise/diaphoresis, excess water intake: can lead to acid-base imbalance, muscle cramps, neuro changes from low sodium (hyponatremia) Toxicity Hypertension, especially w/ kidney disease Food sources - Table salt, cured meat, canned soups, processed food Excess sodium can lead to what chronic disease? Hypertension What is the main dietary source of sodium? Table salt What is salt sensitivity?

Potassium Functions Water balance Blood pressure Muscle action Insulin release from beta cells (pancreas) Explain that sodium and potassium work with each other to maintain water balance. Mention that sodium is extracellular and potassium is intracellular. Does potassium raise or lower blood pressure?

Potassium, cont’d Requirements – no specific RDA *Amer. diet low 2-3 g/day Deficiency – hypokalemia – muscle cramps Toxicity – hyperkalemia, can cause severe heart arrythmias, caution w/ kidney disease Food sources Fruits, vegetables, whole grains, fresh meats Oranges, bananas, tomatoes, potatoes, broccoli, leafy greens FOOD SOURCES – ORANGES, BANANAS, POTOTOES, TOMATOES, BROCCOLI, LEAFY GREENS – LOTS OF POTASSIUM LOST DURING COOKING AND BOILING When are potassium deficiencies more likely to occur? During clinical situations such as prolonged vomiting or diarrhea, during use of diuretic drugs, during use of hypertension drugs, as a result of severe malnutrition, or after surgery What is the result of extremely high potassium levels? Fatal arrhythmia Do most Americans meet the AI for potassium each day?

Chloride Functions Digestion Key element in hydrochloric acid secretion Respiration – works with CO2 in maintaining acid base balance Emphasize that chloride is needed for digestion of all foods through hydrochloric acid.

Chloride, cont’d Requirements – no specific RDA AI: 2.3 g/day Deficiency – rare, excessive vomiting may result in acid/base imbalance Food sources Table salt Sea salt *both contain NaCl What is the primary reason for chloride deficiency? Excessive fluid losses through vomiting, which leads to metabolic alkalosis The only known development of toxicity is through dehydration.

Magnesium Functions General metabolism Protein synthesis Found in all body cells Works with 300+ enzymes to produce energy Protein synthesis Activates amino acids Muscle action – aids w/ nerve impulses, stimulation of muscle contraction Where in the body is magnesium found? In all body cells; it has widespread metabolic functions. Review what a catalyst is. Why are catalysts important? Discuss basal metabolic rate and how magnesium deficiency could influence it.

Magnesium, cont’d Requirements ~300 to 400 mg/day (increases w/ age and preg) Deficiency – rare, may be seen w/ vomiting & starvation, can cause muscle cramping/weakness Toxicity – rare, caution w/ kidney disease Food sources - Nuts, soybeans, cocoa, seafood, peas, green vegetables What are some of the deficiency symptoms? Muscle weakness and cramps, hypertension, and blood vessel constriction in the heart and brain Which individuals are at greater risk for developing magnesium toxicity? Those with renal insufficiency Which sources are relatively poor sources of magnesium? Most fruits, except bananas; milk; meat; and fish .

Trace Elements Iron Iodine Zinc Selenium Fluoride Copper Manganese Chromium Molybdenum Cobalt Boron Vanadium Nickel <100 mg/day needed.

Iron Essential for life, but dangerous when in excess Functions Hemoglobin synthesis (Hg carries O2 to cells) General metabolism Proper glucose metabolism Antibody production Collagen synthesis Conversion of beta-carotene to vitamin A 70% of the body’s iron occurs where? In red blood cells Iron is most well known for its role in hemoglobin and therefore its essentiality in oxygen transport.

Iron, cont’d Requirements (increase w/ age and pregnancy) 8 to 11 mg/day for males 8 to 18 mg/day for females Deficiency states Anemia (decreased RBC’s) Toxicity – can be fatal Hemochromatosis (iron overload – can cause organ damage) Food sources: meats, eggs, fortified cereals, liver, better absorbed w/ Vit C What is one clinical test to determine iron-deficiency anemia? Hemoglobin levels, hematocrit Why do women need more iron than men? Menses Explain that hemochromatosis is a genetic condition enabling the body to retain more iron than needed. Discuss the signs and symptoms of iron-deficiency anemia.

Iodine Functions Requirements Participation in thyroid gland’s synthesis of thyroxine, hormone required for metabolism Requirements 150 mcg/day (minimum 50-75) What is the function of thyroxine? Regulates metabolic rate Where is the thyroid gland located?

Iodine, cont’d Deficiency states Toxicity symptoms - rare Food sources Goiter (enlarged thyroid gland) Cretinism (dwarfism, MR – due to lack of iodine during pregnancy) Hypothyroidism (wt. gain, hair loss, dry skin, cold intolerance) Hyperthyroidism – Graves disease (wt.loss, tremors, nervousness/restless) Toxicity symptoms - rare Food sources Iodized table salt, seafood What is the difference between hypothyroidism and hyperthyroidism? Low t4 vs. high t4 Cretinism results from a mother eating insufficient amounts of iodine during fetal development. What are the characteristics of cretinism? .

Goiter Describe the process of how iodine deficiency leads to goiter. Figure information: B, From Swartz MH: Textbook of physical diagnosis, ed 5, Philadelphia, 2006, Saunders. Copyright © 2009, by Mosby, Inc. an affiliate of Elsevier, Inc. All rights reserved.

Zinc Functions Requirements Important during growth & pregnancy Important for immune system Requirements 11 mg/day for males 8 mg/day for females Zinc is especially important during what growth periods? Pregnancy, lactation, infancy, childhood, and adolescence Who reported the lowest zinc intake on the National Health and Nutritional Examination Survey? Children aged 1 to 3 years, adolescent girls, and persons older than 71 years

Zinc, cont’d Deficiency Toxicity – N/V w/ overuse Food sources Poor wound healing, hair loss Impaired taste and smell Dwarfism, impaired sexual maturation Toxicity – N/V w/ overuse Food sources Meat, seafood, legumes, whole grains Zinc is often supplemented for patients with open wounds.

Selenium Functions Requirements Food sources Antioxidant, aids in protection from free radicals Requirements RDA: 55 mcg/day Brittle hair and nails w/ deficiency Food sources Seafood, kidney, liver; depends on soil content Selenium functions with specific proteins as an essential part of an antioxidant enzyme, glutathione peroxidase, which protects cells and their lipid membranes from oxidative damage. It also functions as a part of the protein center of teeth and participates in the regulation of thyroid hormone action and vitamin C activity. A mild selenium deficiency can have what effect? It may decrease a person’s ability to fight infection. Severe deficiency may put individuals at risk for certain types of cancer.

Other Trace Elements Fluoride Functions by preventing dental carries Prevent cavities, hardens tooth enamel Important for dental health What is fluorosis? When is it critical to watch fluoride intake so fluorosis does not occur? Explain why copper is called iron’s twin. They have many of the same functions. Manganese toxicity can result from mining.

Mineral Supplementation Life cycle needs Pregnancy and lactation - need more Mg, Iron, Zinc, Iodine, Selenium Adolescence – more Ca and Phos Adulthood – mineral supp not needed, balanced diet is more important Clinical needs Iron-deficiency anemia (adol, preg) Zinc deficiency (vegetarians at risk) Special needs during growth periods and in clinical situations may require individual supplements of specific major minerals or trace elements. Plant foods have little zinc – vegetarians at risk – sources of zinc = meat, seafood Ask students to name five high-risk groups that may need to supplement their diet and explain why. Adolescent girls on poor diets, low-income adolescent boys, athletes, vegetarians, and elderly persons on poor diets

Applying Knowledge The camp nurse gives a talk to the camp staff about the signs of fluid volume deficit. She encourages the counselors to be sure the campers drink fluids throughout the day. One counselor responds, “Oh, that’s no problem. The kids guzzle flavored ice tea all day long.” How should she respond? Copyright © 2009, by Mosby, Inc. an affiliate of Elsevier, Inc. All rights reserved.