Learning ObjectivesChapter 12 – Water and the Major MineralsAfter completing Chapter 12, the student will be able to:1. List the uses of water in the body.2. Describe water balance and the sources of water for the body.3. Describe the effects of inadequate and excessive intakes of water.4. Identify the daily Adequate Intake for total water.5. Explain the hormonal regulation of body water to maintain blood volume and blood pressure.6. Explain the role of electrolytes in maintaining water and acid-base balance.7. Describe the role of the kidneys in maintaining homeostasis.8. Describe minerals, and classify them as major or trace minerals.9. Identify the role of sodium in the body and the effects of excessive or inadequate sodium.10. Identify the food sources of sodium and the daily Tolerable Upper Intake Level.11. Identify the role of chloride in the body.12. Describe the role of potassium in the body and effects of excessive and inadequate intake.13. Identify food sources of potassium.14. Describe the role of calcium in the body and the factors that enhance or limit its absorption from thediet.15. Identify food sources of calcium and the recommended dietary intake of calcium.16. Describe the effects of calcium deficiency.17. Identify the role or phosphorus in the body, recommended intake, and food sources.18. Identify the role of magnesium in the body, food sources of magnesium, and the effects of inadequateintake.19. Identify the role of sulfate of the body.20. Discuss osteoporosis, including bone development and disintegration and the two major types ofosteoporosis.21. Identify the risk factors for the development of osteoporosis and the roles of physical activity andcalcium intake.22. Discuss the selection of a calcium supplement.I. Water and the Body FluidsThe main role of water is to maintain an appropriate water balance to support vital functions. Tomaintain water homeostasis, intake from liquids, foods, and metabolism must equal losses from thekidneys, skin, lungs, and feces.A. Water’s roles in the body1. Carries nutrients and waste products.2. Maintains the structure of large molecules.3. Participates in metabolic reactions.4. Solvent for minerals, vitamins, amino acids, glucose, and others.5. Lubricant and cushion around joints, inside the eyes, the spinal cord, and in amniotic fluidduring pregnancy.6. Regulation of body temperature.7. Maintains blood volume.B. Water Balance and Recommended Intakes1. Intracellular fluid (inside the cells) makes up about two-thirds of the body’s water.2. Extracellular fluid (outside the cells) has two components—the interstitial fluid andplasma.3. Water Intakea. Thirst is a conscious desire to drink and is regulated by the mouth, hypothalamus, andnerves.b. Dehydration occurs when water output exceeds input due to an inadequate intake orexcessive losses.
1. Symptoms of a 1%-2% loss of body weight include thirst, fatigue, weakness, vaguediscomfort, and loss of appetite.2. Symptoms of a 3%-4% loss of body weight include impaired physical performance,dry mouth, reduction in urine, flushed skin, impatience, and apathy.3. Symptoms of a 5%-6% loss of body weight include difficulty in concentrating,headache, irritability, sleepiness, impaired temperature regulation, and increasedrespiratory rate.4. Symptoms of a 7%-10% loss of body weight include dizziness, spastic muscles, lossof balance, delirium, exhaustion, and collapse.c. Water intoxication is excessive water contents in all body fluid compartments leading toa dangerous condition known as hyponatremia.4. Water sources include water, other beverages, fruit, vegetables, meat, cheese, and thebyproduct of metabolism. An intake of 1450 to 2800 milliliters of water is usually representedby:a. Liquids – 550 to 1500 mL.b. Foods – 700 to 1000 mL.c. Metabolic water – 200 to 300 mL.5. Water losses occur through urine output, water vapor from the lungs, sweating, and feces. Anoutput of 1450 to 2800 milliliters of water is usually represented by:a. Kidneys – 500 to 1400 mL.b. Skin – 450 to 900 mL.c. Lungs – 350 mL.d. GI tract – 150 mL.6. Water Recommendationsa. 1.0 to 1.5 mL/kcal expended for adults (approximately 2-3 liters for a 2,000 kcalorieexpenditure.b. 1.5 mL/kcal expended for infants and athletes.c. ½ cup per 100 kcal expended.d. Adequate Intake for males is 3.7 L/day.e. Adequate Intake for females is 2.7 L/day.f. Both caffeine and alcohol can have a diuretic effect.7. Health Effects of Watera. Meeting fluid needs.b. Protects the bladder, prostrate, and breast against cancer.c. Protects against kidney stones.8. Kinds of watera. Hard water1. Water with high calcium and magnesium content.2. Leaves residues.3. May benefit hypertension and heart disease.b. Soft water1. Water with high sodium and potassium content.2. May aggravate hypertension and heart disease.3. Dissolves contaminant minerals in pipes.4. Practical advantages.c. Other types of water:1. Artesian water – water drawn from a well that taps a confined aquifer in which thewater in under pressure.2. Bottled water – drinking water sold in bottles3. Carbonated water – water that contains carbon dioxide gas, either natural or added.4. Distilled water – free of dissolved minerals.5. Filtered water – water treated by filtration with lead, arsenic, and somemicroorganisms removed.6. Mineral water – water from a spring or well that contains at least 250 parts permillion of minerals.7. Natural water – water from a spring or well that is certified to be safe and sanitary.
8. Public water – water from a city or county water system that has been treated anddisinfected.9. Purified water – water that has been treated to remove dissolved solids.10. Spring water – water originating from an underground spring or well.11. Well water – water drawn from ground water by tapping into an aquifer.C. Blood Volume and Blood Pressure – Fluids are essential to the regulation of blood volume andblood pressure.1. ADH and water retentiona. Antidiuretic hormone (ADH) is released from the pituitary gland and causes kidneys toreabsorb water, thus preventing losses.b. Vasopressin is another name for ADH.2. Renina. Kidneys release renin to reabsorb sodium.b. Helps to restore blood pressure and blood volume.3. Angiotensina. With the assistance of renin, angiotensinogen is hydrolyzed to angiotensin I.b. An enzyme converts angiotensin I to angiotensin II.c. Angiotensin II is a vasoconstrictor that raises blood pressure by narrowing bloodvessels.4. Aldosteronea. Angiotensin II mediates the release of aldosterone from the adrenal glands.b. Kidneys retain sodium in order to retain water.D. Fluid and Electrolyte Balance – Several minerals including sodium, chloride, potassium, calcium,phosphorus, magnesium, and sulfur are involved in fluid balance.1. Dissociation of Salt in Watera. Dissociates into positive ions called cations and negative ions called anions.b. Ions carry electrical current so they are called electrolytes.c. Solutions are called electrolyte solutions.d. Positive and negative charges inside and outside the cell must be balanced.e. Milliequivalents is the concentration of electrolytes in a volume of solution.2. Electrolytes Attract Watera. Water molecules are neutral, polar.b. Oxygen is negatively charged. Hydrogen is positively charged.c. Enables body to move fluids.3. Water Follows Electrolytesa. Sodium and chloride are primarily outside the cell.b. Potassium, magnesium, phosphate, and sulfur are primarily inside the cell.c. Osmosis is the movement of water across the cell membrane toward the moreconcentrated solutes.d. Osmotic pressure is the amount of pressure needed to prevent the movement of wateracross a cell membrane.4. Proteins Regulate Flow of Fluids and Ionsa. Proteins attract water and regulate fluid balance.b. Transport proteins regulate the passage of positive ions.c. Negative ions follow.d. Water flows toward the more concentrated solution.e. The sodium-potassium pump uses ATP to exchange minerals across the cell membrane.5. Regulation of Fluid and Electrolyte Balancea. Digestive juices of GI tract contain minerals and these are reabsorbed as needed.b. Kidneys maintain fluid balance using ADH.c. Kidneys maintain electrolyte balance using aldosterone.E. Fluid and Electrolyte Imbalance – Medications and medical conditions may interfere with thebody’s ability to regulate the fluid and electrolyte balance.1. Different Solutes Lost by Different Routesa. Vomiting or diarrhea causes sodium losses.b. Kidneys may lose too much potassium if there is adrenal hypersecretion of aldosterone.
c. Uncontrolled diabetics may lose glucose and fluid via the kidneys.2. Replacing Lost Fluids and Electrolytesa. Drink plain cool water and eat regular foods for temporary small losses.b. Greater losses require oral rehydration therapy (ORT) (½ L boiling water, 4 tsp sugar,and ½ tsp salt). Cool before giving.F. Acid-Base Balance – The body must maintain an appropriate balance between acids and bases tosustain life. Acidity in measured by the pH value, the concentration of hydrogen atoms.1. Regulation by the Buffersa. First line of defense.b. Carbonic acid and bicarbonate can neutralize acids and bases.c. Carbon dioxide forms carbonic acid in the blood that dissociates to hydrogen ions andbicarbonate ions.2. Regulation in the Lungsa. Respiration speeds up and slows down as needed to restore homeostasis.3. Regulation in the Kidneysa. Selects which ions to retain and which to excrete.b. The urine’s acidity level fluctuates to keep the body’s total acid content balanced.II. The Minerals—An OverviewMajor minerals are found in large quantities in the body, while trace minerals are found in smallquantities. Minerals receive special handling in the body. They may bind with other substances andinteract with other minerals, thus affecting absorption.A. Inorganic Elements1. Major minerals or macrominerals retain their chemical identity when exposed to heat, air,acid, or mixing.2. Minerals can be lost when they leach into water.B. The Body’s Handling of Minerals1. Some behave like water-soluble vitamins.2. Some behave like fat-soluble vitamins.3. Excessive intake of minerals can be toxic.C. Variable Bioavailability1. Binders in food can combine chemically with minerals and prevent their absorption.2. Phytates are found in legumes and grains.3. Oxalates are found in spinach and rhubarb.D. Nutrient Interactions1. Sodium and calcium.2. Phosphorus and magnesium.3. Often caused by supplements.E. Varied Roles1. Sodium, potassium, and chloride function primarily in fluid balance.2. Calcium, phosphorus, and magnesium function primarily in bone growth and health.III. SodiumSodium is one of the primary electrolytes in the body and is responsible for maintaining fluid balance.Dietary recommendations include a moderate intake of salt and sodium. Excesses may aggravatehypertension. Most of the sodium in the diet is found in table salt and processed foods.A. Sodium Roles in the Body1. Maintains normal fluid and electrolyte and acid-base balance.2. Assists in nerve impulse transmission and muscle contraction.3. Filtered out of the blood by the kidneys.B. Sodium Recommendations1. Minimum adults: 500 mg/day2. Adequate Intakea. For those 19-50 years of age, 1,500 mg/day.
. For those 51-70 years of age, 1,300 mg/day.c. For those older than 70 years of age, 1,200 mg/day.3. The upper intake level for adults is 2,300 mg/day.4. Maximum % Daily Value on food labels is set at 2400 mg/day.C. Sodium and Hypertension1. Salt has a great impact on high blood pressure. Salt restriction does help to lower bloodpressure.2. Salt sensitivity is a term to describe individuals who respond to a high salt intake with highblood pressure.3. Dietary Approaches to Stop Hypertension (DASH) is a diet plan that helps to lower bloodpressure.D. Sodium and Bone Loss (Osteoporosis)1. High sodium intake is associated with calcium excretion.E. Sodium in Foods1. Large amounts in processed foods (approximately 75% of sodium in the diet).2. Table salt (approximately 15% added sodium in the diet).3. Sodium may be present in surprisingly high amounts if chloride is removed.4. Moderate amounts in meats, milks, breads, and vegetables (approximately 10% of sodium inthe diet).F. Sodium Deficiency1. Sodium and water must be replaced after vomiting, diarrhea, or heavy sweating.2. Symptoms are muscle cramps, mental apathy, and loss of appetite.3. Salt tablets without water induce dehydration.4. Be careful of hyponatremia during ultra-endurance athletic activities.G. Sodium Toxicity and Excessive Intakes1. Edema and acute hypertension.2. Prolonged high intake may contribute to hypertension.IV. ChlorideChloride in an essential nutrient that plays a role in fluid balance. It is associated with sodium and partof hydrochloric acid in the stomach.A. Chloride Roles in the Body1. Maintains normal fluid and electrolyte balance.2. Part of hydrochloric acid found in the stomach.3. Necessary for proper digestion.B. Chloride Recommendations and Intakes1. Recommendationsa. Adequate Intake1. For those 19-50 years of age, 2,300 mg/day.2. For those 51-70 years of age, 2,000 mg/day.3. For those older than 70 years of age, 1,800 mg/day.b. Upper intake level is 3,600 mg/day.2. Chloride intakesa. Abundant in foods.b. Abundant in processed foods.C. Chloride Deficiency and Toxicity1. Deficiency is rare.2. Losses can occur with vomiting, diarrhea, or heavy sweating.3. Dehydration due to water deficiency can concentrate chloride to high levels.4. The toxicity symptom is vomiting.V. PotassiumPotassium is another electrolyte associated with fluid balance. It is associated (inversely) withhypertension. It is found in fresh foods—mostly fruits and vegetables.
A. Potassium Roles in the Body1. Maintains normal fluid and electrolyte balance.2. Facilitates many reactions.3. Supports cell integrity.4. Assists in nerve impulse transmission and muscle contractions.5. Maintains the heartbeat.B. Potassium Recommendations and Intakes1. Adequate Intake – For all adults, 4,700 mg/day.2. Fresh foods are rich sources.3. Processed foods have less potassium.C. Potassium and Hypertension1. Low potassium intakes increase blood pressure.2. High potassium intakes prevent and correct hypertension.D. Potassium Deficiency1. Symptoms include muscular weakness, paralysis, confusion, increased blood pressure, saltsensitivity, kidney stones, and bone turnover.2. Later signs include irregular heartbeats, muscle weakness, and glucose intolerance.E. Potassium Toxicity1. Results from supplements or overconsumption of potassium salts.2. Can occur with certain diseases or treatments.3. Symptoms include muscular weakness and vomiting.4. If given into a vein, potassium can cause the heart to stop.VI. CalciumMost of calcium (99%) is found in the bones. The remaining calcium (1%) is found in the blood andhas many functions. Bone and blood calcium are kept in balance with a system of hormones andvitamin D. Blood calcium remains in balance at the expense of bone calcium and at the risk ofdeveloping osteoporosis in later years.A. Calcium Roles in the Body1. Calcium in Bonesa. Hydroxyapatite are crystals of calcium and phosphorus.b. Mineralization is the process whereby minerals crystallize on the collagen matrix of agrowing bone, hardening of the bone.c. There is an ongoing process of remodeling constantly taking place.2. Calcium in Body Fluidsa. Calmodulin is an inactive protein that becomes active when bound to calcium and servesas an interpreter for hormone and nerve-mediated messages.b. Ionized calcium has many functions.3. Calcium and Disease Preventiona. May protect against hypertension.b. DASH diet that is rich in calcium, magnesium, and potassium.c. May be protective relationship with blood cholesterol, diabetes, and colon cancer.4. Calcium and Obesitya. Maintaining healthy body weight.b. Calcium from dairy foods has better results than calcium from supplements.c. More research is needed.5. Calcium Balancea. Works with vitamin D.b. Works with parathyroid hormone and calcitonin.c. Calcium rigor develops when there are high blood calcium levels and causes themuscles to contract.d. Calcium tetany develops when there are low blood calcium levels and causesuncontrolled muscle contractions.e. Abnormalities are due to problems with hormone secretion or lack of vitamin D.
f. Bones get robbed of calcium before blood concentrations get low.6. Calcium Absorptiona. Absorption rate for adults is 30% of calcium consumed.b. Calcium-binding protein is needed for calcium absorption.c. Factors that enhance absorption1. Stomach acid.2. Vitamin D.3. Lactose.4. Growth hormones.d. Factors that inhibit absorption1. Lack of stomach acid.2. Vitamin D deficiency.3. High phosphorus intake.4. High-fiber diet.5. Phytates in seeds, nuts, and grains.6. Oxalates in beet greens, rhubarb, and spinach.B. Calcium Recommendations and Sources1. Calcium Recommendationsa. AI adolescents: 1300 mg/day.b. AI adults: 1000 mg/day if 19-50 years of age.c. AI adults: 1200 mg/day if greater than 50 years of age.d. Upper level for adults: 2500 mg/day.e. Peak bone mass is the bone’s fullest potential in size and density developed in the firstthree decades of life.2. Calcium in Milk Productsa. Drink milk.b. Eat yogurt and cheese.c. Add dry milk during food preparation.3. Calcium in Other Foodsa. Tofu, corn tortillas, some nuts, and seeds.b. Mustard and turnip greens, broccoli, bok choy, kale, parsley, watercress, and seaweed(nori).c. Legumes.d. Oysters and small fish consumed with bones.e. Mineral waters, calcium-fortified orange juice, fruit and vegetable juices, and highcalciummilk.f. Calcium-fortified cereals and breads.D. Calcium Deficiency1. Osteoporosis is the disease where the bones become porous and fragile due to mineral losses.2. No obvious symptoms of mineral loss in bones appear. It is silent.3. Deficiency in children can present as stunted growth.4. Toxicity symptoms include constipation, increased risk of urinary stone formation, kidneydysfunction, and interference with the absorption of other minerals.VII. PhosphorusMost of the phosphorus is found in the bones and teeth. It is also important in energy metabolism, aspart of phospholipids, and as part of genetic materials.A. Phosphorus Roles in the Body1. Mineralization of bones and teeth.2. Part of every cell.3. Genetic material (DNA and RNA).4. Part of phospholipids.5. Energy transfer.6. Buffer systems that maintain acid-base balance.B. Phosphorus Recommendations and Intakes
1. RDA adults: 700 mg/day for ages 19-70 years.2. Upper intake level for those 19-70 years of age is 4,000 mg/day.3. Sources include all animal foods including meat, fish and poultry, milk, and eggs.C. Phosphorus toxicity symptoms include the calcification of nonskeletal tissues, especially thekidneys.VIII. MagnesiumMagnesium supports bone mineralization, and is involved in energy systems and in heart functioning.It is widespread in foods.A. Magnesium Roles in the Body1. Bone mineralization.2. Building of protein.3. Enzyme action.4. Normal muscle contraction.5. Nerve impulse transmission.6. Maintenance of teeth by preventing dental caries.7. Functioning of the immune system.8. Blood clotting.B. Magnesium Intakes1. RDA adult men: 400 mg/day for 19-30 years of age.2. RDA adult women: 310 mg/day for 19-30 years of age.3. Upper level for adults: 350 mg nonfood magnesium/day.4. Nuts and legumes, whole grains, dark green vegetables, seafood, chocolate, and cocoa.5. Hard water and some mineral waters.C. Magnesium Deficiency1. Deficiencies are rare.2. Symptomsa. Weakness and confusion.b. Convulsions in extreme deficiency.c. Bizarre muscle movements of the eye and face.d. Hallucinations.e. Difficulties in swallowing.f. Growth failure in children.3. Develops from alcohol abuse, protein malnutrition, kidney disorders, and prolonged vomitingand diarrhea.D. Magnesium and Hypertension1. Protects against heart disease and hypertension.2. Low magnesium restricts walls of arteries and capillaries.E. Magnesium Toxicity1. Symptoms from nonfood magnesium are diarrhea, alkalosis, and dehydration.IX. SulfateSulfate requirements are met by consuming a varied diet. It is found in essential nutrients includingprotein. There is no recommended intake and there are no known deficiencies (apart from PEM).X. Highlight: Osteoporosis and CalciumOsteoporosis is one of the most prevalent diseases of aging. Strategies to reduce risks involve dietarycalcium.A. Bone Development and Disintegration1. Cortical bone is the outer shell compartment of bone.a. Creates the shell of long bones.b. Creates the shell caps on the end of bones.c. Releases calcium slower than trabecular bone.d. Losses can begin in the 40s.
2. Trabecular bone is the inner lacy matrix compartment of bone.a. Can be affected by hormones in the body signaling the release of calcium.b. Provides a source for blood calcium when needed.c. Losses can become significant in the 30s for men and women.1. Results in type I osteoporosis.2. Can result in spine and wrist fractures and loss of teeth.3. Women are affected 6 times as often as men.3. Losses of both trabecular and cortical bone result in type II osteoporosis.a. Can result in compression fractures of the spine.b. Hip fractures can develop.c. Twice as common in women as in men.4. The diagnosis of osteoporosis is performed using bone density tests.5. Individual risk factors for osteoporosis are also considered.B. Age and Bone Calcium1. Maximizing Bone Massa. Children and adolescents need to consume enough calcium and vitamin D to createdenser bones.b. With a higher initial bone mass, the normal losses of bone density that occur with agewill have less detrimental effects.2. Minimizing Bone Lossa. Ensuring adequate intakes of vitamin D and calcium are consumed.b. Hormonal changes can increase calcium losses.C. Gender and Hormones1. Men at lower risk than women.2. Hormonal changes.3. Rapid bone loss in nonmenstruating women.4. Two main classes of medication can be useda. Antiresorptive agents, which block bone resorption.b. Anabolic agents, which stimulate bone formation.5. Soy offers some protection.D. Genetics and Ethnicity1. Genes may play a role: risk for African Americans < for Caucasians < Asians orCentral/South Americans.2. Environment also – diet and calcium.3. Physical activity, body weight, alcohol, and smoking have a role.E. Physical Activity and Body Weight1. Muscle strength and bone strength go together.2. Heavy body weights and weight gains place a stress on bones and promote bone density.F. Smoking and Alcohol1. Smokersa. Less dense bones.b. Damage can be reversed when smoking stops.2. Alcohol abusea. Enhances fluid excretion, thus increases calcium losses.b. Upsets hormonal balance for healthy bones.c. Slows bone formation.d. Stimulates bone breakdown.e. Increases risks of falling.G. Dietary Calcium – the key to preventionH. Other Nutrients1. Adequate protein.2. Adequate vitamin D.3. Vitamin K protects against hip fractures.4. Vitamin C may slow bone loss.5. Magnesium and potassium help to maintain bone mineral density.6. Vitamin A.
7. Omega-3 fatty acids.8. Fruits and vegetables.9. Reduce salt.10. Phytochemicals such as lycopene.I. A Perspective on Supplements1. Calcium-rich foods are best.2. Supplements may be needed when requirements are not met through foods.3. Types of supplementsa. Antacids contain calcium carbonate.b. Bone meal or powdered bone, oyster shell or dolomite are calcium supplements.c. Contain lead??d. Small doses are better absorbed.e. Calcium generally absorbed equally well from Ca carbonate, citrate, or phosphate, buttablet disintegration is important.J. Some Closing Thoughts – Age, gender, and genetics are beyond control. There are effectivestrategies for prevention that include adequate calcium and vitamin D intake, physical activity,moderation of alcohol, abstaining from cigarettes, and supplementation if needed.