Final Review and Assessment of Profile and Nutritional Health – FSM 159 Nutrition - 30 points After you have completed your IProfile analysis and your personal iProfile questions - you must now review

Chapter 8 Water and Minerals Water • Essential nutrient that is often overlooked. Water in the Body • In adults, water accounts for 60% of body weight. • Different proportions in different tissues: o About 75% of muscle. o About 25% of bone. • Intracellular fluid: water inside of cells. o About one -third of the body water. • Extracellular fluid: water outside of cells. o About two -thirds of the body water. o Includes the water in the blood and lymph, the water between cells, and the water in the digesti ve tract, eyes, joints, and spinal cord. • The distribution between intra - and extracellular fluid depends on differences in the concentrations of dissolved substances, or solutes. o Examples: proteins, sodium and potassium. o The concentration drive osmosis: th e diffusion of water in a direction that equalizes the concentration of dissolved substances on either side of a membrane. • Blood pressure: the amount of force exerted by the blood against the walls of arteries. o Forces water from the capillary blood vessels into the spaces between the cells of the surrounding tissues. Water Balance • Cannot be stored in the body. • Intake and output must be balanced to maintain the right amount. • Most water consumed comes from water and liquids that we drink. o Solid foods also provide water; most fruits and vegetables are over 80% water. o Small amount of water is produced as a by -product of metabolic reactions. • Water loss: urine and feces, evaporation from the lungs and skin, and in sweat. • Regulating water intake: o Thirst: sensation that signals the need to drink. ▪ Caused by dryness in the mouth. ▪ Powerful urge that lags behind the need for water. ▪ Cannot be relied on alone to maintain water balance. • Regulating water loss: o The kidneys: regulate water loss in urine. ▪ About 1 to 2 L/day. ▪ Varies depending on consumption and amount of waste to be excreted . ▪ Act as a filter. ▪ Antidiuretic hormone (ADH) signal s the kidneys to reabsorb water, reducing the amount lost in urine. ▪ Also affected by the amount of sodium in the blood , blood volume, and blood pressure . The Functions of Water • Essential to life; does not provide energy. • Water in metabolism and transport: o An excellent solvent: glucose, amino acids, minerals, proteins and other substances. o Participates in reaction s that join small molecules together or break apart large ones. o Help maintain the acidity of the body. o Primary constituent of blood. • Water as protection: o Bathes cells of the body. o Lubricates and cleanses internal and external body surfaces. ▪ Example: tear s lubricate eyes and wash away dirt. ▪ Water in synovial fluid lubricates joints. ▪ Water in saliva lubricates the mouth, helping chewing and swallowing. o Resists compression. ▪ Cushions the joints and other parts of the body against shock. ▪ Example: amniotic sac protects the fetus as it grows inside the uterus. • Water and body temperature: o Helps regulate body temperature by increasing or decreasing the amount of heat lost at the surface of the bo dy. o Cooling is aided by the production of sweat. Water i n Health and Disease • Dehydration: water loss exceeds water intake. o Causes a reduction in blood volume, which impairs the ability to deliver oxygen and nutrients to cells and remove waste products. o Early symptoms: thirst, headache, fatigue, loss of appetite , dry eyes and mouth, and dark -colored urine. o Affects physical and cognitive performance. o As dehydration worsens, it causes: nausea, difficulty concentrating, confusion, and disorientation. o Can become severe and require medical attention. o Water loss of 10 -20% of body weight can be fatal. o Groups at risk: ▪ Older adults because thirst mechanism becomes less sensitive with age. ▪ Infants because their body surface area relative to their weight is much greater than that of adults, so they lose proportionately mo re water through evaporation; also their kidneys cannot concentrate urine efficiently. o Rehydration saves lives: dehydration due to diarrhea is a major cause of childhood death in the world. • Overhydration ( Water intoxication ): condition that occurs when a person drinks enough water to significantly lower the concentration of sodium in the blood. o Water moves out of the blood vessels into the tissues by osmosis causing them to swell. o Swelling of the brain can cause disorientation , convulsions, coma, and death . o Early symptoms are similar to dehydration: nausea, muscle cramps, disorientation, slurred speech, and confusion. Meeting Water Needs • Need more water than any other nutrient. • AIs: 3.7 L /day for men and 2.7 L/day for women. • Varies with activity, environme ntal temperature and humidity, and diet. o Activity increases water need as the amount of sweat increases. o A high -protein diet increases water needs because the urea produced from protein breakdown is excreted in urine. o A low -calorie diet increases water ne eds because as body fat and protein are broken down for fuel, ketones and urea are produced and must be excreted. o A high -salt diet increases water losses because the excess must be excreted in the urin e. o A high fiber diet increases water needs because more water is held in the intestines and excreted in the feces. • Diuretic: a substance that increases the amount of urine passed from the body. o Caffeine: effect in the course of an entire day is probably small. o Alcohol: depends on the amount of water and alcohol in the beverage is consumed. DEBATE: Is Bottled Water Better? • The Issue: Americans consume about 36 gallons of bottled water per person per year. It is convenient and we may think it tastes better and is safer than tap water. But the cost to our pocketbook and the environment is high? Should we be drinking from the tap? An Overview of Minerals • Minerals: elements needed by the body in small amount to maintain structure and regulated chemical reactions and body processes. • Major minera ls: required in the diet in amounts greater than 100 mg/day or present in the body in amounts greater than 0.01% of body weight. o Includes: sodium, potassium, chloride, calcium, phosphorous, magnesium, and sulfur. • Trace minerals: minerals required in the di et in amounts of 100 mg or less/day or present in amounts of 0.01% of body weight or less. o Includes: iron, copper, zinc, selenium, iodine, chromium, fluoride, manganese, molybdenum. Minerals in Our Food • Minerals are found in both plant and animal sources. • Some are present as functioning components of the plant or animal. o Present in consistent amounts. o Example: iron content of beef. • Some are present as contaminants from the soil or processing. o Examples: plants grown in an area where the soil is high in selenium. o Milk from dairies that use sterilizing solutions that contain iodine. • Added to food intentionally during processing. o Examples: sodium as a flavor enhancer. o Iron added to enriched grains. o Calcium, iron, and others added to fortified breakfast cere als. • Handling and p rocessing can remove minerals from foods. o Examples: when vegetables are cooked. o When skins of fruits and vegetables or the bran and germ of grain are detached. Mineral Bioavailability • Bioavailability in foods consumed varies. o Can vary f rom food to food, meal to meal, and person to person. • Minerals in animal products are better absorbed that those in plant foods. o Plants contain substances that bind minerals in the GI tract and reduce absorption. ▪ Phytic acids, tannins, oxalates, and fiber. • Compounds that interfere with absorption: o Oxalates: spinach, rhubarb, beet greens, and chocolate. ▪ Interfere with absorption of calcium and iron. o Phytates: found in whole grains, bran and soy products. ▪ Bind calcium, zinc, iron, and magnesium; limiting absorption. ▪ Can be broken down by yeast. Bioavailability higher in yeast -leavened bread. o Tannins: found in tea and some grain. ▪ Interferes with absorption of iron. • The presence of one mineral can interfere with the absorption of others. o Ion: an at om or a group of atoms that carries an electrical charge. o Minerals that carry the same charge compete in the intestinal tract. ▪ Examples: calcium, magnesium, zinc, copper, and iron. ▪ Generally not a problem when whole foods are consumed. ▪ A large dose from a dietary supplement may interfere with the absorption of other minerals. • The body’s need for a mineral may affect how much of that mineral is absorbed. o Example: if plenty of iron is stored, less will be absorbed. • Life stages can affection absorption. o Examples: calcium absorption doubles during pregnancy. Mineral Functions • Minerals contribute to the body’s structure. • Help regulate body processes. • Many serve more than one function. o Example: calcium needed for bone strength and mai ntaining a normal blood pressure, allow muscles to contract, and transmit nerve signals between cells. • Help regulate water balance. • Help regulate energy production. • Affect growth and development through their role in the expression of certain genes. • Act as cofactors needed for enzyme activity. o Cofactor: an inorganic ion or coenzyme that is required for enzyme activity. • None of the minerals act in isolation. o Interact with each other as well as other nutrients and components in the diet. Understanding Minera l Needs • Need to choose a variety of foods from each of the food groups. • Some minerals are found in large amounts in a limited amount of food. o Example: best sources calcium are dairy products and leafy greens. If these foods are not included in the diet then the addition of fortified foods or supplements is needed • Some found in small amounts in many foods, depending on where it ’s grown or processed, so variety of foods from different locations is needed to meet needs. • Some minerals in minute quantities are present due to the environment. • Deficiency can lead to major health consequences. • DRI’s set for 7 major minerals and 9 trace minerals. • Current Nutrition Facts panel on food label required to list amount of sodium, calcium, and iron plus potassium will be added to the planned Nutrition Facts panel Electrolytes: Sodium, Potassium, and Chloride • Electrolytes: positively or negatively charged ions that conduct an electrica l current in solution. • Refers to sodium, potassium, and chloride. • Important for maintain ing fluid balance and nerve impulse transmission. Electrolytes in the Body • Sodium and potassium carry a positive charge. o Potassium is the principle positively charged intracellular ion. o Sodium is the principle positively charged extracellular ion. • Chloride is the principle negative charge d extracellular ion . • Salt or table salt: sodium chloride. • Functions of electrolytes: o Help regulate fluid balance. o Essential for generating and conducting nerve impulses. • Regulating electrolyte balance: o Thirst and salt appetite help ensure that appropriate proportions of salt and water are taken in. o Kidneys are the primary regulator of concentrations in the bo dy. ▪ Blood pressure regulation. Electrolyte Deficiency and Toxicity • Electrolyte deficiencies and toxicities are uncommon in healthy people. • Electrolyte deficiency: deficiencies of any electrolyte can lead to electrolyte imbalances . o Can cause disturbances in poor appetite, muscle cramps, confusion, apathy, constipation , and acid -base and fluid balance . o Example: sudden death can occur from an irregular heartbeat as a result of fasting, anorexia nervosa or starva tion o Electrolyte losses may be in creased by heavy and persistent sweating, chronic diarrhea or vomiting, or kidney disorders. o Medications can also interfere with electrolyte balance. ▪ Example: some diuretics used to treat high blood pressure cause potassium loss. • Electrolyte toxicity: not possible for healthy people to consume too much potassium from foods. o Potassium supplements consumed in excess can increase blood levels of potassium and potentially cause death due to an irregular heartbeat. ▪ If too much potassium enters the blood, it can cause the heart to stop. o Difficult to consume more sodium than the body can handle. ▪ Generally drink more water when sodium is consumed. • Hypertension: high blood pressure. Most common disease associated with electrolyte imbalance. o Called “the silent killer ” because n o outward symptoms. o Can lead to atherosclerosis, heart attack, stroke, kidney disease, and early death. o Caused by an increase in blood volume and/ or narrowing of the blood vessels. o Treated with diet, exercise, and medication. o Healthy blood pressure: 120/80 mm of mercury or less. o Prehypertension: blood pressure between 120/80 and 139/89 mm mercury. o Hypertensi on: blood pressure consistently 140/90 mm mercury or above. o Risk Factor s: ▪ Genetics: family history of the disease. ▪ Race: more common in African Americans. ▪ Age: increases with age. ▪ Overweight, particularly excess fat in the abdominal region. ▪ Lack of physica l activity. ▪ Heavy alcohol consumption. ▪ Stress. o Public health concern: 1/3 of American adults age 20 and older are diagnosed with it but only 53% of those diagnosed have their blood pressure under control. • Diet and blood pressure: o High sodium diets associa ted with hypertension. o Diets high in potassium, calcium, and magnesium are associated with lower average blood pressure. o The DASH diet: Dietary Approaches to Stop Hypertension eating plan; shown to reduce blood pressure significantly ▪ Plenty of fiber, potas sium, magnesium, and calcium. ▪ Low in total fat, saturated fat, and cholesterol. ▪ Lower in sodium than the typical American diet. Meeting Electrolytes Needs • 2300 mg sodium or less for adults: 2015 -2020 Dietary Guidelines and UL • 1500 mg sodium or less: people with prehypertension and hypertension . • Average US intake of sodium: 34 40 mg /day . o Salt is 40% sodium and 60% potassium by weight. o This represents 8 .6 g ( 86 00 mg) of salt per day. • 4700 mg potassium/day: DRIs. • 3500 mg potassium/ day: Daily Value. o No UL for potassium. • Ty pical US intake of potassium: 26 00 mg /day . • Processing adds sodium and chloride to the diet. o Over three -quarters of the salt eaten in from foods that have had salt added during processing and manufacturing . o 77% of sa lt in the diet comes from processed foods. o 12% of salt comes naturally in foods. o 11% of salt is added during cooking or at the table. • Sodium added for flavoring and as a preservative • Fresh, unprocessed foods are high in potassium: fruits, vegetables, whole grains . • Sodium on food labels: o Health claim can be made if the product is low -sodium that is may reduce the risk of high blood pressure o Health claim can be made if product is low -sodium and a good source of potassium that it may reduce t he risk of high blood pressure and stroke . o Sodium free: food contains less than 5 mg of sodium/serving . o Low sodium: food contains 140 mg or less sodium/serving. (about 5% of the daily value). o Reduced sodium: food contains at least 25% or less sodium per se rving than the reference food . What Should I Eat? Water and Electrolytes • Stay hydrated • Increase potassium intake • Decrease sodium intake Minerals and Bone Health • Bones are the hardest, strongest structures in the body. • Bone is composed of a protein framework (matrix consisting mostly of collagen) that is hardened by deposits of minerals. • Mineral portion of bone is composed mainly of calcium associated with phosphorous. o Also contains magnesium, sodium, fluoride, etc. • Health bone requires adequ ate dietary protein and vitamin C to maintain collagen. • Healthy bone requires a sufficient supply of calcium and other minerals to assure solidity. • Adequate vitamin D is needed to maintain appropriate levels of calcium and phosphorous. • Vitamin K may also b e important. • Loss of bone mass with age increasing risk of fractures (osteoporosis). Osteoporosis • Bone is alive. • Bone remodeling: a continuous process in which bone is broken down and replaced by new bone. • Most bone is formed early in life. • Bone mass cont inues to increase into young adulthood. • Peak bone mass: the maximum bone density at tained at any time in life . o Achieved somewhere between ages 16 and 30. • Osteoporosis: a bone disorder characterized by reduced bone mass, increased bone fragility, and increased risk of fractures. • Factors affecting the risk of osteoporosis: o Gender: more common in women than men. ▪ Postmenopausal bone loss: accelerated bone loss that occurs in women for about five to ten years after the menstrual cycle stops. o Age: risk incr eases with age. o Race: African Americans have denser bones than do Caucasians and Southeast Asians. o Family history. o Body weight : those who are small and light have an increased risk. o Smoking: tobacco weakens bones. o Exercise: weight bearing exercise throughout life strengthens bones. o Alcohol abuse: long -term abuse reduces bone formation and interferes with the absorption of calcium. o Diet: diet lacking in calcium and vitamin D plays a major role in development. • Preventing and treating osteoporosis: o Ac hieve a high peak bone mass early in life. o Slow the rate of bone loss. o Diet with adequate calcium and vitamin D. o Higher intakes of zinc, magnesium, potassium, fiber , vitamin K, and vitamin C. ▪ Found in fruits and vegetables. o Maintaining an active lifestyle. ▪ Includes weight -bearing exercise. ▪ Limit smoking. ▪ Limit alcohol consumption. o Treatment: estrogen to reduce bone breakdown and increase calcium absorption. ▪ Other hormones or drugs: bisphosphonates. ▪ Weight bearing activity. Calcium • 1.5% of body weight is due to calcium. o 99% found in bones and teeth. o Remaining in body cells and fluids. • Needed for muscle contraction, release of neurotransmitters, blood pressure regulations, cell communication, blood clotting, and other essential functions. • Calcium in health and disease: o Parathyroid hormone (PT H) is released when calcium levels drop. o Calcitonin is released if blood calcium levels become too high. o Bone resorption: when too little calcium is consumed, the body maintains normal blood levels by breaking down bone to release calcium. o Low calcium intake during the years of bone formation results in lower peak bone mass. o Elevated blood calcium can cause: loss of appetite, abnormal heart beat, weight loss, fatigue, frequent urination and soft tissue calcification . ▪ Severe elevation may cause confusion, delirium, coma, and even death. ▪ Rare. Most often caused by cancer and disorders that increase the secretion of PTH. ▪ Can also result from increases in intestinal calcium absorption due to excessive vitamin D intake or high intakes of calcium from supplements or antacids. o High calcium intake from supplements can interfere with the availability of iron, zinc, magnesium, an d phosphorous. Causes constipation, and elevated blood and urinary calcium. ▪ May promote the formation of kidney stones. • Meeting calcium needs: o 1000 mg Calcium per day: adults ages 19 to 50. ▪ Men ages 50 to 70. o 1200 mg Calcium per day: women ages 50 to 70. ▪ Both genders over age 70. o Main food source: dairy products. ▪ Other food sources: leafy dark green vegetables, fish consumed with bones, foods processed with calcium – juices and breakfast cereals. o Supplements: can help to meet needs. ▪ High bioavailability: • Vitamin D. • Acidic foods, lactose, and fat. ▪ Low bioavailability: • Oxalates, phytates, tannins, and fiber. Thinking Critically: Soda versus milk • How will the trend away from milk consumption affect the incidence of osteoporosis 30 years from now? Phosphorus • Most is associated with calcium as part of the hard mineral crystals in bones and teeth. o Smaller amoun t in soft tissue : an essential role as a structural component of phospholipids, DNA and RNA, and ATP. o Important in regulating enzyme activity and maintaining acidity in cells. • Phosphorous in health and disease: kidneys help maintai n phosphorus levels in a ratio with calcium. • Deficiency: can lead to bone loss, weakness, and loss of appetite. o Inadequate intake: rare. o May be caused by chronic diarrhea or poor absorption due to overuse of aluminum -containing antacids. • Excessive intake: can lead to bone loss. o Concern that increased use of food additives that contain phosphorous (soft drinks) may affect bone health. • UL: 4000mg/da y for adults. • Meeting phosphorus needs: dairy products, meat, cereals, bran, eggs, nuts, and fish. o Food additives in baked goods, processed meat, carbonated beverages, etc . Magnesium • Essential for bone health. o About 50 -60% of magnesium helps maintain bone structure. o Rest in cells and fluids. • Involved in regulating calcium homeostasis and is needed for the action of vitamin D and many hormones. • Important for blood pressure regulation. • Needed in every metabolic reaction that generates or uses ATP. • Magnesium in health and disease: o Deficiency is rare. o Typical intake is below RDA. o Low intake associated with chronic diseases including osteoporosis , Type 2 diabetes, hypertension, and atherosclerosis . ▪ Deficiency can cause: nausea, muscle weakness and cramping, irritability, mental derangements, and changes in blood pressure and heartbeat. o Toxicity: no adverse effects from food. ▪ Drugs containing magnesium (example: milk of magnesia): cause nausea, vomiting, low blood pressure, and other cardiovascular c hanges. ▪ UL: 350 mg for adults and adolescents over age 9. • Meeting magnesium needs: found in many foods in small amounts. o Single food sources are limited. Fluoride • Helps prevent dental caries by strengthening tooth enamel in both children and adults. • Inco rporated into the mineral crystals in bones and teeth. • Meeting fluoride needs: o Present in small amounts in almost all water, plants, and animals. o Richest dietary sources: toothpaste, tea, and marine fish consumed with their bones. o Water sources can provide fluoride. Foods cooking with fluoride containing water absorb fluoride. ▪ Teflon cooking utensils can pick up fluoride. ▪ Aluminum cookware can decrease the fluoride content of foods. ▪ Bottled water usually does not contain fluoride. • Recommended intake: o 0.05 mg/kg/day: 6 months and older ▪ About 3.8 mg/day for a 76 -kg man. ▪ About 3.1 mg/day for a 61 -kg woman o Fluoridated water provides about 0.7 mg fluoride/liter. o Supplements: ▪ American Academy of Pediatrics suggests a supplement of 0.25 mg/day for children 6 months to 3 years; ▪ 0.5 mg/day for children ages 3 to 6 years; ▪ 1.0 mg/day for those ages 6 to 16 years. ▪ Available by prescription for children living in areas with low fluoride concentration in the water. • Fluoridation of water: o Added to public wa ter supplies to promote dental health. o 75% of the population is served by public water supplies. • Toxicity: o Fluorosis: condition caused by chronic over -consumption of fluoride, characterized by black and brown stains and cracking and pitting of the teeth. ▪ Chronic ingestions of fluoride -containing toothpaste. o UL: 0.1mg/kg/day for infants and children less than 9 years of age. ▪ 10 mg/day for those 9 years and older. What Should I Eat? Calcium, Phosphorus, Magnesium, and Flouride • Get calcium into your body and your bones • Don’t fret about phosphorus • Maximize your magnesium • Find your flouride Minerals and Healthy Blood • Iron and copper are trace minerals essential for the synthesis of adequate amounts of hemoglobin. Iron • Most iron in the body is in the protein hemoglobin. o Also part of myoglobin. • Essential for ATP production. • Iron -containing proteins are also involved in drug metabolism and immune function. • Iron absorption and transport. o Heme iron: readily absorbable form of iron found in meat, fish, and poult ry. ▪ Absorbed twice as efficiently as nonheme iron. o Nonheme iron: found in plant sources such as leafy green vegetables, legumes and grains. ▪ Absorption can be enhanced or reduced by foods and nutrients consumed in the same meal. o Once absorbed, the amou nt delivered to cells depends to some extent on the body’s needs. • Meeting iron needs: o 8 mg/day: RDA for adult men and postmenopausal women. o 15 mg/day: young women 14 to 18 years. o 18 mg/day: women 19 to 50 years. o Separate recommendations for vegetarians. o Assumes that food sources include both plant and animal proteins. o Iron cookware increases iron content of food. o Absorption decreased by fiber, phytates, tannins, and oxalates. ▪ Calcium may also decrease absorption. • Iron in health and disease. o Iron deficiency anemia: iron deficiency disease that occurs when the oxygen - carrying capacity of the blood is decreased because there is insufficient iron to make hemoglobin. ▪ Symptoms: fatigue, weakness, headache, decreased work capacity, inability to maint ain body temperature in a cold environment, changes in behavior, decreased resistance to infection, impaired development in infants, and increased risk of lead poisoning in children. ▪ Anemia is the last state of iron deficiency. ▪ Most common nutrient deficie ncy. ▪ Risks: • Women of child bearing age, pregnant women, infants, children, adolescents. • Low total iron intake, vegetarian diets, dieting. • Poverty, intestinal parasites. Thinking It Through: A Case Study on Iron Deficiency • Case: 23 -year -old graduate student eating a lacto -ovo vegetarian diet for the past 6 months has a complaint of always being tired. o Toxicity: caused by excessive consumption of iron -containing supplements. ▪ Most common form of poisoning in children under age 6. ▪ UL: 45 mg/day from all sources o Iron overload: accumulation of iron in the body over time . ▪ Hemochromatosis: inherited disorder that results in increased iron absorption. • More than 1 million Americans affected. • Most common genetic disorder in Caucasians. • Symptoms that oc cur in middle -age: nonspecific symptoms such as weight loss, fatigue, weakness and abdominal pain. • Excess iron can damage the heart and liver and increase the risk of diabetes and cancer. • Treatment: regular blood withdrawal. Copper • Interrelated with iron. • Copper deficiency results in iron deficiency which may lead to anemia. • Functions as a component of a number of important proteins and enzymes involved in connective tissue synthesis, antioxidant protection, lipid metabolism, mainten ance of heart muscle, and function of the immune and central nervous system. • Sources: o Seafood, nuts and seeds, whole -grain breads and cereals, and chocolate. o Organ meats: liver and kidney. o Soil content affects the amount of copper in plants. • RDA: 900 micro grams/day. • Deficiency: o Protein collagen does not form normally, resulting in skeletal changes similar to those seen in vitamin C deficiency. o Causes elevated blood cholesterol. o Associated with impaired growth, degeneration of the heart muscle and the nervou s system, and changes in hair color and structure. o Increases incidence the incidence of infections. o Severe deficiency is relatively rare. o Can also occur with high intake of dietary zinc. • Toxicity: o Rare. o Results from drinking contaminated water supplies or consuming acidic foods or beverages. o Most likely to occur from supplements. o Causes pain, vomiting, and diarrhea. o UL: 10 mg/day. Antioxidant Minerals • Antioxidants vitamins (vitamin C and E) protect cells from damaging effects of reactive oxygen molecules. • Minerals (selenium, zinc, copper, and manganese) act as cofactors for antioxidant enzyme systems. Selenium • Amount of selenium in food varies depending on the concentration in the soil. • Keshan disease: a form of heart disease occurs in children and young women in regions of China with low selenium levels. • Incorporated in the structure of certain proteins. o Glutathione peroxidase: selenium -containing enzyme that protects cells from oxidative dama ge by neutralizing peroxides. • Needed for the synthesis of the thyroid hormones, which regulate metabolic rate. • Meeting selenium needs: o Deficiencies and excesses are not a concern in the US. o RDA: 55 µg/day. o Excellent sources: seafood, kidney, liver, and egg s. o Good sources: grains, nuts, and seeds – depending on selenium content of soil. o Poor sources: fruits, vegetables, and drinking water. o UL: 400 µg/ day from diet and supplements. • Selenium and cancer: o Incidence of cancer has been observed where selenium int ake is low. o Role of supplementation is under investigation. Zinc • Most abundant intracellular trace mineral. • Involved in the function of 100 different enzymes. o Vital for protecting cells from free -radical damage. • Maintain adequate levels of metal binding proteins. • Enzymes that function in the synthesis of DNA and RNA, in carbohydrate metabolism, in acid -base balance, and for the absorption of folate. • Plays a role in the storage and release of insulin, the mobilization of vitamin A from the liver, a nd the stabilization of cell membranes. • Influences hormonal regulation of cell division. • Needed for the growth and repair tissues, the activity of the immune system, and the development of sex organs and bone. • Role in gene expression. • Zinc transport from the mucosal cells of the intestine into the blood is regulated. • Meeting zinc needs: o Red meat, liver, eggs, dairy products, vegetables, and seafood. o Absorbed better from animal sources. • Zinc in health and disease: o Deficiency: uncommon in North America. o Imp ortant consequences in developing countries: ▪ Deficiency interferes with growth and development, impairs immune function, and causes skin rashes and diarrhea. ▪ Risk is greater where the diet is high in phytate, fiber, tannins, and oxalates. o Toxicity: not wit h food. ▪ Supplements can cause toxicity symptoms. o Supplements: ▪ No evidence of improved immune function, enhanced fertility and sexual performance. ▪ May be helpful in individuals with mild zinc deficiency. ▪ If taken with 24 hours of cold symptoms, may reduce t he severity and duration of a cold. • UL: 40 mg/day from all sources. Manganese: • A constituent of some enzymes and an activator of others. • Involved in carbohydrate metabolism, and cholesterol metabolism; bone formation; synthesis of urea; and prevention of oxidative damage. • Recommended Intake: 2.3 mg/day for adult men o 1.8 mg/day for adult woman • Dietary sources: whole grains, nuts, legumes, and leafy green vegetables. Sulfur • Part of the proteins in the body and amino acids and vitamins. o Includi ng cysteine, a part of glutathione which is essential for the antioxidant enzyme glutathione peroxidase • No recommended intake level. • No deficiency diseases or symptoms. • Toxicity is not likely. • Sources: prot eins foods, preservatives , and sulfur containing v itamins . Molybdenum: • Needed to activate enzymes. • Functions: in the metabolism of sulfur -containing amino acids and nitrogen -containing compounds present in DNA and RNA. o Production of waste products: uric acid. o Oxidation and detoxification of various other compounds. • Recommended intake: 45 µg/day for adult men and women. • Content in food varies with soil content of molybdenum. • Sources: milk and milk products, organ meats, breads, cereals and legumes. o Readily absorbed from food. o Regulated by excr etion in the urine and bile. Minerals and Energy Metabolism Iodine • Most iodine is found in the thyroid gland. • Essential component of the thyroid hormones. o Regulate metabolic rate, growth, and development, and promote protein synthesis. • Iodine in health a nd disease: o Thyroid hormone levels carefully regulated. ▪ If blood levels drop, thyroid -stimulating hormone is released. o Goiter: an enlargement of the thyroid gland caused by a deficiency of iodine. o Cretinism: a condition resulting from poor maternal iodine intake during pregnancy that impairs mental development and growth in offspring. o Deficiency: most common in regions where soil is low in iodine and there is little access to fish and seafood. ▪ Risk increases with consumption of foods that contain goi trogens: turnips, rutabaga, cabbage, millet, and cassava. ▪ Problem in African countries. o UL: 1100 µg of iodine/day from all sources. • Meeting iodine needs: o Foods from the seas: fish, seafood, and seaweed. o Iodized salt: table salt to which a small amount of s odium iodide or potassium iodide has been added. o RDA: 150 µg/day. o Contaminant and additives in food : used in food dye and cattle feed , used in sterilizing agent for farm equipment . Chromium • Required to maintain normal blood glucose levels. • Dietary sources : liver, brewer’s yeast, nuts, and whole grains. • Intake can be increased by cooking in stainless -steel cookware. • Recommended intake: o 35 µg/day for men age 19 to 50. o 25 µg for women age 19 to 50. • Deficiency: not a problem in the US. • Supplement: chromium picolinate, common. o No evidence of any action. • UL: insufficient data to establish. What Should I Eat? Trace Minerals • Add more iron and increase iron absorption • Think zinc • Trace down your minerals