Major Minerals Tutorial Notes

Objectives qIdentify the main roles, deficiency and toxicity symptoms, and food sources for each of the major minerals : §calcium, phosphorus, magnesium, sulfate §sodium, chloride, potassium Minerals •Minerals: small, naturally occurring, inorganic, chemical elements •Serve as structural components & in many vital processes in the body •Inorganic: being composed of matter other than plant or animal 2 Similarities to Vitamins •Do not contribute energy (calories) to the diet •Have diverse functions within the body •Work with enzymes to facilitate chemical reactions •Required in the diet in very small amounts 3 Differences from Vitamins •Whereas vitamins are organic compounds, minerals are inorganic compounds •Unlike vitamins, some minerals contribute to the building of body structures Classification of minerals • Minerals represent approximately 4% to 5% of body weight • The mineral nutrients are traditionally divided into: • Major minerals: ≥ 100mg/day required • Trace elements : <15 mg/ day required 4 Minerals 5 Classification of minerals •The distinction between the major minerals and the trace minerals does not mean that one group is more important than the other. • A deficiency of the few micrograms of iodine needed daily is just as serious as a deficiency of the several hundred milligrams of calcium. •The major minerals are so named because they are present, and needed, in larger amounts in the body than the trace minerals. I. Major Minerals •Major mineral: an essential mineral nutrient found in the body in amounts greater than 5 grams 6 Function of Major Minerals: •Although all the major minerals influence the body’s fluid balance, sodium, chloride, and potassium are most noted for that role. •Each major mineral also plays other specific roles in the body. •Sodium, potassium, calcium, and magnesium are critical to nerve transmission and •muscle contractions. •Phosphorus and magnesium are involved in energy metabolism. Function of Major Minerals (cont.): •Calcium, phosphorus, and magnesium contribute to the structure of the bones. •Sulfur helps determine the shape of proteins. 7 Calcium Roles in the Body • Most abundant mineral in the body ü99% is stored in the bones qan integral part of bone structure. qServes as a calcium bank available to the body fluids should a drop in blood calcium occur. q1% in body fluids as Ca++ Calcium in Bone is an integral part of bone structure. qAs bones begin to form, calcium salts form crystals on a matrix of the protein collagen. q As the crystals become denser, they give strength and rigidity to the maturing bones. qAs a result, the long leg bones of children can support their weight by the time they have learned to walk. 8 Cross-Section of Bone Calcium in Bone •Bones continuously gain and lose minerals in an ongoing process of remodeling. • Growing children gain more bone than they lose, and healthy adults maintain a reasonable balance. • When withdrawals substantially exceed deposits, however, problems such as osteoporosis develop. 9 10 Phases of Bone Development throughout Life The active growth phase occurs from birth to approximately age 20. The next phase of peak bone mass development The final phase, when bone resorption exceeds formation, begins between the ages of 30 and 40 and continues through the remainder of life. Calcium in Body Fluids • 1 percent of the body’s calcium (Ca++): qRegulates the transport of ions across cell membranes and is particularly important in nerve transmission. qHelps maintain normal blood pressure. qPlays an essential role in the clotting of blood. qIs essential for muscle contraction and therefore for the heartbeat. qAllows secretion of hormones, digestive enzymes, and neurotransmitters. qActivates cellular enzymes that regulate many processes. vBecause of its importance, blood calcium is tightly controlled. 11 Calcium Balance qWhenever blood calcium rises too high, a system of hormones, including vitamin D, promotes its deposit into bone. •Calcitonin: lowers blood calcium by inhibiting release of calcium from bone Calcium Balance (cont.) qWhenever blood calcium falls too low, the regulatory system acts in three locations to raise it: •(1) the small intestine absorbs more calcium • (2) the bones release more calcium into the blood • (3) the kidneys excrete less calcium. •Thus, blood calcium rises to normal. •Parathormone: raises blood calcium. 12 The calcium stored in bone provides a nearly inexhaustible source of calcium for the blood. • The calcium stored in bone provides a nearly inexhaustible source of calcium for the blood. • Even in a calcium deficiency, blood calcium remains normal. • Blood calcium changes only in response to abnormal regulatory control. • A chronic deficiency of calcium due to a low dietary intake or poor absorption does not change blood calcium, but does deplete the calcium in the bones. • It is the bones, not the blood, that are robbed by calcium deficiency. Calcium and Osteoporosis • As mentioned earlier, bone mass peaks at the time of skeletal maturity (about age 30), and a high peak bone mass is the best protection against later age-related bone loss and fracture. • Adequate calcium nutrition during the growing years is essential to achieving optimal peak bone mass. • Following menopause, women may lose up to 20 percent of their bone mass, as may middle-aged and older men. • When bone loss has reached such an extreme that bones fracture under even common, everyday stresses, the condition is known as osteoporosis. 13 • Both genetic and environmental factors contribute to osteoporosis; Table 9-6 summarizes these risk factors. • Osteoporosis is more prevalent in women than men for several reasons: • First, women consume less dietary calcium than men do. • Second, at all ages, women’s bone mass is lower than men’s because women generally have smaller bodies. • Finally, women often lose more bone, particularly in the 6 to 8 years following menopause when the hormone estrogen diminishes. 14 Risk factors for osteoporosis qNonmodifiable • Female gender • Older age • Small frame • Caucasian, Asian, or Hispanic/ Latino heritage • Family history of osteoporosis or fractures • Personal history of fractures • Estrogen deficiency in women (amenorrhea or menopause, especially early or surgically induced); • testosterone deficiency in men Risk factors for osteoporosis (cont.) • Modifiable • Sedentary lifestyle • Diet inadequate in calcium and vitamin D • Diet excessive in sodium, caffeine • Cigarette smoking • Alcohol abuse • Low body weight • Certain medications, such as glucocorticoids and anticonvulsants 15 How to prevent osteoporosis? qIn addition to calcium, many other minerals and vitamins, including phosphorus, magnesium, fluoride, and vitamin D, help to form and stabilize the structure of bones. § Any or all of these elements are needed to prevent bone loss. vThe first, most obvious lines of defense, however, are to maintain a lifelong adequate intake of calcium § and to “exercise it into place.” vPhysical activity supports bone growth during adolescence and may protect the bones later on. • Weight-bearing physical activity, such as walking, running, dancing, and weight training, prompts the bones to deposit minerals. • It has long been known that, when people are confined to bed, both their muscles and their bones lose strength. • Muscle strength and bone strength go together: when muscles work, they pull on the bones, and both are stimulated to grow stronger. Calcium and Disease Prevention qCalcium may protect against hypertension. •The blood pressure-lowering DASH diet is not particularly low in sodium, but it is rich in calcium, as well as in potassium and magnesium. q Calcium-rich foods may play a role in reducing body fat, protecting lean tissue, and maintaining a healthy body weight. 16 17 Nutritional Problems Deficiency Symptoms •Stunted growth in children •Bone loss (osteoporosis) in adults Toxicity Symptoms •Excess is usually excreted so toxicity is rare 18 Calcium requirements vary by age If this is your age 0 to 6 months 7 to 12 months 1 to 3 years 4 to 8 years 9 to 18 years 19 to 50 years Over 50 years Then you need this much calcium each day (mg) 210 270 500 800 Growth 1,300 spurt 1,000 1,200 Source: The 2004 Surgeon General’s Report on Bone Health and Osteoporosis: What It Means to You at http://www.surgeongeneral.gov/library/bonehealth 47 • An optimal calcium intake reflects the amount needed to retain the most calcium. • The more calcium retained, the greater the bone density (within genetic limits) and, potentially, the lower the risk of osteoporosis. • Calcium recommendations during adolescence are set high (1300 milligrams) to help ensure that the skeleton will be strong and dense. • Between the ages of 19 and 50, recommendations are lowered slightly, • and for women over 50 and all adults over age 70, recommendations are raised again to minimize bone loss. • Many people in the United States have calcium intakes below current recommendations. • Findings about the effectiveness of calcium supplements in reducing fractures in older women, however, are inconclusive or negative. • Because adverse effects such as kidney stone formation are possible with high supplemental doses, a UL has been established (2500mg/d)). 19 Many people in the United States have calcium intakes below current recommendations. 49 DRI & Sources •DRI = 1000 mg – 1300 mg •Foods •Milk/milk products •Dark green vegetables •Some fish & shellfish •Tofu & other legumes •Fortified foods (i.e.: juices) 20 51 21 % DV calcium: Milk group Choose fat-free or low fat most often • Yogurt 1 cup (8 oz.) = 30% DV • Milk 1 cup = 30% DV • Cheese 1 ½ oz. natural/2 oz. processed = 30% DV • Milk pudding 1/2 cup = 15% DV • Frozen yogurt, vanilla, soft serve ½ cup = 10% DV • Ice cream, vanilla ½ cup = 8% DV • Soy or rice milk, calcium-fortified 1 cup = varies—check label 53 ways of adding calcium to meals • Those who tolerate milk can slip extra calcium into meals by sprinkling a tablespoon or two of fat-free dry milk into almost everything. • The added kcalorie value is small, and changes to the taste and texture of the dish are practically nil. Yet each • 2 tablespoons adds about 100 extra milligrams of calcium and moves people closer to meeting the recommendation to obtain 3 cups of milk each day. • Here are some more tips for including calcium-rich foods in your meals. 22 tips for including calcium-rich foods in your meals. 23 % DV calcium: Vegetable group • Broccoli, raw 1 cup = 9% DV • Collards 1/2 cup = 20% DV • Turnip greens, boiled 1/2 cup = 10% DV 59 24 • Some dark green, leafy vegetables—notably, spinach and Swiss chard—appear to be calcium rich but • actually provide very little, if any, calcium to the body. These foods contain binders • that prevent calcium absorption. Calcium-fortified FOODS • Some foods offer large amounts of calcium because of fortification • Calcium-fortified juice, high-calcium milk (milk with extra calcium added), and calcium-fortified cereals are examples. • Some calcium-rich mineral waters may also be a useful source, providing calcium that may be as absorbable as that from milk but accompanied by zero kcalories. 25 Calcium-fortified FOODS • Aided by vitamin D, the body is able to regulate its absorption of calcium by altering • its production of the calcium-binding protein. More of this protein is made if • more calcium is needed. Infants and children absorb up to 60 percent of the calcium • they ingest, and pregnant women, about 50 percent. Other adults, who are not growing, • absorb about 25 to 30 percent.27 26 27 Additional dietary considerations 71 Food is the best calcium source • There may be additional substances in foods that affect the body’s absorption and use of their calcium. • A balanced diet that promotes a healthy weight may provide additional benefits to protect against osteoporosis. 72 28 • People may think that taking a calcium supplement is preferable to getting calcium from food, but foods offer important fringe benefits. • For example, drinking 3 cups of milk fortified with vitamins A and D will supply substantial amounts of other nutrients. • Furthermore, the vitamin D and possibly other nutrients in the milk enhance calcium absorption. • Some people absorb calcium better from milk and milk products than from even the most absorbable supplements. • The National Institutes of Health • concludes that foods are the best sources of calcium and recommends supplements only when intake from food is insufficient 29 Calcium amount at one time • Body can best handle about 500 mg calcium at one time from food and/or supplements. • Consume calcium sources throughout day instead of all at one time. 75 Upper daily limits: calcium & vitamin D The National Academy of Sciences suggests the following tolerable daily upper intake levels (UL) from foods and supplements combined: • Calcium: The UL for 1 year and older (including pregnant and lactating women) is 2,500 mg/day. It was not possible to establish an UL for infants under age 1. 76 30 Help for the lactose-intolerant Some people lack the enzyme lactase needed to digest lactose (lactase). Here are some tips which may help people obtain calcium from dairy products… 77 Start with small portions of foods such as milk and gradually increase serving size. 78 31 Eat dairy foods in combination with a meal or solid foods. 79 Try dairy foods other than milk: • Many hard cheeses (cheddar, Swiss, Parmesan) have less lactose than milk • Yogurt made with live, active bacteria 80 32 It may be easier to digest lactose that is pre-digested or broken down to its simple sugar components (glucose and galactose): • Lactose-hydrolyzed milk and dairy products • Commercial lactase preparations 81 33 Calcium is absorbed by two mechanisms: qActive transport, • which operates predominantly at low luminal concentrations of calcium ions, qpassive transport or paracellular transfer, • which operates at high luminal concentrations of calcium ions. 34 Ca absorption qAided by vitamin D, the body is able to regulate its absorption of calcium by altering its production of the calcium-binding protein. •More of this protein is made if more calcium is needed. üInfants and children absorb up to 60 percent of the calcium they ingest, and pregnant women, about 50 percent. üOther adults, who are not growing, absorb about 25 to 30 percent. Factors influence absorption of calcium: qIncreased needs enhance calcium absorption : • growth, • pregnancy, • lactation, • calcium-deficient states, or qVitamin D qExercise resulting in high bone density. 35 Factors that decrease Ca absorption •Phytic Acid ( ↓calcium, iron, zinc, magnesium) • Oatmeal & Whole grains & nuts •Oxalic Acid (calcium & iron) • Beet greens, rhubarb & spinach , Swiss chard •Fiber •Caffeine SWISS CHARD 36 Oxalic acid •Doesn’t seem to affect calcium in other foods •These greens still good for you; may help calcium absorption in other ways 89 37 Factors that increase Ca excretion •Sodium Excessive sodium • Can increase urinary calcium excretion • Food and Nutrition Board recommends limit of 2,300 mg daily 94 38 Phosphorous •2nd most abundant mineral in the body (85% combined with calcium) •Functions: •Structure of bones & teeth •Necessary for growth (DNA) •Energy metabolism (ATP) Phosphorous vPhosphorus is the second most abundant mineral in the body. qAbout 85 percent of it is found combined with calcium in the crystals of the bones and teeth. qAs part of one of the body’s buffer systems (phosphoric acid), phosphorus is also found in all body tissues. qPhosphorus is a part of DNA and RNA, the genetic material present in every cell. q §Thus, phosphorus is necessary for all growth. 39 Phosphorous qPhosphorus also plays many key roles in the transfer of energy that occurs during cellular metabolism. qPhosphorus-containing lipids phospholipids) help transport other lipids in the blood. qPhospholipids are also principal components of cell membranes. 40 NUTRITIONAL PROBLEMS Deficiency symptoms • Muscle weakness • Bone pain • Phosphorous deficiency is rare • Found widely in foods Toxicity symptoms • Calcification of nonskeletal tissues, particularly the kidneys • May cause calcium excretion and hinder absorption DRI & Sources •DRI = 700 mg •Foods •Meat, poultry & fish •Dairy products •Processed foods •Soda 41 Phosphorous •Animal protein is the best source of phosphorus because the mineral is so abundant in the cells of animals. • Milk and cheese are also rich sources. •Diets that provide adequate energy and protein also supply adequate phosphorus. •Dietary deficiencies are rare. 42 Magnesium •Functions: (DRI = 350 mg) •Present in bone and teeth •Protein synthesis •Enzyme action (co-factor) •Normal muscle contraction & relaxation •Nerve transmission Magnesium •Magnesium barely qualifies as a major mineral. • Only about 1 ounce of magnesium is present in the body of a 130-pound person, qmore than half of it in the bones. §Bone magnesium seems to be a reservoir to ensure that some will be on hand for vital reactions regardless of recent dietary intake. qMost of the rest is in the muscles, heart, liver, and other soft tissues, qwith only 1 percent in the body fluids. 43 Magnesium qMagnesium is critical to the operation of hundreds of enzymes and other cellular functions. • It acts in all the cells of the soft tissues, where it forms part of the protein-making machinery and is necessary for the release of energy. qMagnesium and calcium work together for proper functioning of the muscles: • calcium promotes contraction, • and magnesium helps relax the muscles afterward. qMagnesium is also critical to normal heart function. qLike many other nutrients, magnesium supports the normal functioning of the immune system and inflammatory response Magnesium •Functions: (DRI = 350 mg) •Present in bone and teeth •Protein synthesis •Enzyme action (co-factor) •Normal muscle contraction & relaxation •Nerve transmission 44 Magnesium Deficiency ücan result from : • Inadequate intake • vomiting, • diarrhea, • alcohol abuse, or • malnutrition; • in people who have been fed nutritionally incomplete fluids intravenously for too long after surgery; • in people using diuretics Magnesium deficiency symptoms • low blood calcium level, • muscle cramps, and • seizures. • Magnesium deficiency is thought to cause the hallucinations commonly experienced during withdrawal from alcohol intoxication. • In addition, magnesium deficiency may worsen inflammation associated with many chronic diseases and may increase the risk of stroke and sudden death by heart failure, even in otherwise healthy people. • Low intakes of magnesium may have adverse effects on bone metabolism and increase the risk for osteoporosis as well. 45 Magnesium Toxicity • Magnesium toxicity is rare, but it can be fatal. • Toxicity occurs only with high intakes from nonfood sources such as supplements or magnesium salts. • Accidental poisonings may occur in children with access to medicine cabinets and in older adults who abuse magnesium-containing laxatives, antacids, and other medications. • The consequences include; • diarrhea, abdominal cramps, and, in severe cases, acid–base imbalance and potassium depletion. Magnesium Intakes and Food Sources • Although average magnesium intakes typically fall below recommendations, deficiency symptoms are rare in healthy people. • In some areas of the country, the water naturally contains both calcium and magnesium. • This so-called “hard” water can contribute significantly to magnesium intakes. 46 Food Sources •Dark green vegetables •Nuts •Legumes •Whole grains whole-grain breads and cereals •Seafood •Chocolate & cocoa •Magnesium •is easily lost from foods during processing, so unprocessed foods are the best choices. 47 Sulfate • Sulfate is the oxidized form of sulfur as it exists in foods and water. • The body requires sulfate for the synthesis of many important sulfurcontaining compounds. • Sulfur-containing amino acids play an important role in helping to shape strands of protein.* The particular shape of a protein enables it to do its specific job, such as enzyme work. • Skin, hair, and nails contain some of the body’s more rigid proteins, which have high sulfur contents. • There is no recommended intake for sulfur, and no deficiencies are known. • Only a person who lacks protein to the point of severe deficiency will lack the sulfur-containing amino acids. • The sulfur-containing amino acids are methionine and cysteine. Cysteine in one part of a protein chain can bind to cysteine in another part of the chain by way of a sulfur-sulfur bridge, thus helping to stabilize the protein structure. 48 Insulin figure Sulfur •Functions: •Present in all proteins (structure) •Part of biotin & thiamin •Part of insulin 49 Food Sources •All protein- containing foods 50 Sodium •An electrolyte •Electrolyte: compound that partially dissociates in water to form ions •primary regulator of the extracellular fluid volume • Chief positive charged ion outside of cells •Sodium also helps maintain acid–base balance •is essential to muscle contraction and nerve transmission. •When the blood concentration of sodium rises, as when a person eats salted foods, •thirst prompts the person to drink water until the appropriate sodium-to-water ratio is restored. 51 •When the blood concentration of sodium rises, as when a person eats salted foods, •thirst prompts the person to drink water until the appropriate sodium-to-water ratio is restored. 52 Sodium recommendation •Diets rarely lack sodium, and even when intakes are low, the body adapts by reducing sodium losses in urine and sweat, thus making deficiencies unlikely. •Sodium recommendations are set low enough to protect against high blood pressure but high enough to allow an adequate intake of other nutrients. •AI: 1.5 gr/kg 53 Sodium recommendation •Because high sodium intakes correlate with high blood pressure, •the Tolerable Upper Intake Level (UL) for adults is set at 2300 milligrams per day— •equivalent to about 1 teaspoon of salt (sodium chloride). Sodium recommendation qThree groups of people are urged to limit their sodium intakes to no more than 1500 milligrams per day for the sake of their blood pressure and heart health 1. all those age 51 and older, 2. all African Americans, 3. everyone with hypertension, diabetes, or chronic kidney 54 55 •People who eat foods high in salt often happen to be eating fewer potassiumcontaining foods at the same time. •Notice how potassium is lost and sodium is gained as foods become more processed, causing the potassium-tosodium ratio to fall dramatically. •Even when potassium is not lost, the addition of sodium still lowers the potassium-to-sodium ratio. Top Contributors of Sodium in the Diet • Breads and rolls • Cold cuts and cured meats • Pizza • Fresh and processed poultry • Soups • Sandwiches (including cheeseburgers) • Cheese • Pasta dishes • Meat mixtures (including meatloaf) • Salty snacks (including popcorn, chips, and pretzels) 56 Sodium and Blood Pressure • High intakes of salt among a population correlate with high rates of hypertension, heart disease, and stroke. • Over time, a high-salt diet may damage the linings of blood vessels in ways that make hypertension likely to develop. • In many people, the relationship between salt intake and blood pressure is direct—as chronic sodium intakes increase, blood pressure rises with them in a stepwise fashion. • Once hypertension sets in, the risk of death from stroke and heart disease climbs steeply. • Because reducing salt intake diminishes the risk of hypertension and heart disease, • the Dietary Guidelines for Americans advise limiting daily sodium intakes to less • than 2300 milligrams (or ,1500 mg for the at-risk groups mentioned above). 57 Deficiency & Toxicity Symptoms •Deficiency symptoms: •Muscle cramps •Mental apathy •Loss of appetite •Toxicity symptoms: •High blood pressure 58 Hypertension – Risk factors •Obesity •Family history •Race (African American) •Age •Excess alcohol intake •Sedentary lifestyle Nutrition in Action: Diet & Blood Pressure 59 Hypertension prevention & treatment • An eating pattern proven to help people to reduce sodium and increase potassium intakes, and thereby often reduce their blood pressure, is DASH (Dietary Approaches to Stop Hypertension). • The DASH approach emphasizes potassium-rich fruits and vegetables and fat-free or low-fat milk products; includes whole grains, nuts, poultry, and fish; and calls for reduced intakes of red and processed meats, sweets, and sugar-containing beverages. • The DASH diet in combination with a reduced sodium intake is even more effective at lowering blood pressure than either strategy alone • Incorporating physical activity provides further benefits because regular moderate exercise reliably lowers blood pressure. DASH = “Dietary Approaches to Stop Hypertension” • High intake of fruits and vegetables (8-10 sv/day) • Low-fat daily products (2-3 sv/day) • Low-fat, low-saturated fat, low-cholesterol • Sodium less than 2400 mg/day 60 Potassium • An electrolyte (Chief positive ion inside cells) • Functions: • May lower blood pressure • Protein synthesis • Fluid balance • Nerve transmission • Contraction of muscles • Critical for maintaining heartbeat • Deficiency arises in abnormal conditions such as diabetic acidosis, dehydration, • or prolonged vomiting or diarrhea; potassium deficiency can also result from the • regular use of certain medications, including diuretics, steroids, and cathartics. 61 • Potassium toxicity does not result from overeating foods high in potassium; therefore, a UL was not set. • Toxicity can result from overconsumption of potassium salts or supplements and from certain diseases or medications. • Given more potassium than the body needs, the kidneys accelerate their excretion. • If the GI tract is bypassed, however, and potassium is injected directly into a vein, it can stop the heart. Deficiency Symptoms •Muscle weakness •Paralysis •Confusion •Can cause death •Accompanies dehydration •Unlikely but can occur with increase in sodium intake 62 Toxicity Symptoms •Causes muscular weakness •Triggers vomiting Intake & Sources •AI= 4.7 gr/d •Whole foods- including meats, milk, fruits, vegetables, grains, legumes •The more processed a food, the less potassium it contains 63 64 Chloride •An electrolyte •Functions: •Part of hydrochloric acid found in the stomach •Necessary for proper digestion •Fluid balance Deficiency Symptoms •Growth failure in children •Muscle cramps •Mental apathy •Loss of appetite 65 Toxicity Symptoms •Normally harmless •Disturbed acid-base balance 66