Water and the Major Minerals

1. Water and the Major Minerals Chapter 12

2. Water and the Body Fluids • Water constitutes majority of body weight • Body composition • Females • Obese people • Elderly

3. Water and the Body Fluids • Carries nutrients and waste products • Maintains structure of large molecules • Participates in metabolic reactions • Serves as a solvent • Acts as a lubricant and cushion • Aids in regulation of body temperature • Maintains blood volume

4. Water Balance and Recommended Intake • Cellular fluids • Intracellular fluid • Extracellular fluid • Interstitial fluid • Intravascular fluid

5. Water Balance and Recommended Intake • Water intake • Thirst and satiety • Mouth, hypothalamus, and nerves • Thirst response lags behind the body’s need for water • Dehydration symptoms • Water intoxication • Symptoms

6. Signs of Dehydration

7. Water Balance and Recommended Intake • Sources • Water • Beverages • Foods • Condensation reactions • Oxidation of energy-yielding nutrients

8. Water Balance and Recommended Intake • Losses • Minimum excretion each day as urine • Vapor from lungs • Sweat from skin • Loss in feces • Recommendations • Needs vary • AI for total water

9. Water Balance and Recommended Intake • Health effects • Meet bodily needs • Protect against urinary stones & constipation • Concentration, alertness, and short-term memory • Type of water • Hard water • Soft water

10. Blood Volume and Blood Pressure • Kidneys are central to blood volume and pressure maintenance • Antidiuretic hormone (ADH) • Hypothalamus stimulates pituitary gland • Water-conserving hormone • Stimulates kidneys to reabsorb water • Events trigger thirst

11. Nephron Function in the Kidney

12. Blood Volume and Blood Pressure • Renin • Enzyme released by kidney cells when blood pressure is low • Kidneys reabsorb sodium • Water retention • Angiotensin • Renin hydrolyzes angiotensinogen to angiotensin I • Convert to active form – angiotensin II

13. Blood Volume and Blood Pressure • Aldosterone • Released from adrenal glands • Release stimulated by angiotensin II • Signals kidneys • Excrete potassium • Retain sodium

14. How the Body Regulates Blood Volume

15. Fluid and Electrolyte Balance • Fluid balance • Two-thirds inside the cells • One-third outside the cells • Dissociation of salt • Sodium – cation • Chloride – anion • Conduct electricity

16. Fluid and Electrolyte Balance • Electrolytes attract water • Water molecules have net charge of zero • Water follows electrolytes • Electrolytes predominantly outside of cell • Sodium and chloride • Electrolytes predominantly inside of cell • Potassium, magnesium, phosphate, sulfate • Selectively permeable membranes

17. Water Dissolves Salts and Follows Electrolytes

18. A Cell and Its Electrolytes

19. Osmosis

20. A B A B A B Water can flow both ways across the divider, but has a greater tendency to move from side A to side B, where there is a greater concentration of solute. The volume of water becomes greater on side B, and the concentrations on side A and B become equal. Now additional solute is added to side B. Solute cannot flow across the divider (in the case of a cell, its membrane). With equal numbers of solute particles on both sides of the semipermeable membrane, the concentrations are equal, and the tendency of water to move in either direction is about the same. Stepped Art Fig. 12-6, p. 391

21. Fluid and Electrolyte Balance • Proteins regulate fluid movement • Attract water • Transport proteins • Passage of ions across cell membranes • Sodium-potassium pump • Regulation of fluid and electrolyte balance • Two sites • GI tract • Kidneys

22. Fluid and Electrolyte Imbalance • Causes of imbalance • Prolonged vomiting or diarrhea • Heavy sweating • Burns • Traumatic wounds • Some medications • An imbalance can result in a medical emergency

23. Fluid and Electrolyte Imbalance • Solutes lost depend on why fluid is lost • Vomiting or diarrhea – sodium • Tumor development – potassium • Replacing lost fluids and electrolytes • Plain cool water and regular foods • Special replacement fluids

24. Acid-Base Balance • Regulation of acidity • Narrow pH range to avoid life-threatening consequences • Denaturation of proteins • Concentration of hydrogen ions • High hydrogen concentration – acidic • Low hydrogen concentration – basic

25. The pH Scale

26. Acid-Base Balance • Body defense against pH fluctuation • Buffers in blood • Bicarbonate • Carbonic acid • Respiration in lungs • Excretion in kidneys • Bicarbonate

27. Bicarbonate-Carbonic Acid Buffer System

28. The Minerals – An Overview • Major vs. trace minerals • Variation in amounts needed • Inorganic elements • Always retain chemical identity • Cannot be destroyed by heat, air, acid, or mixing • Body’s absorption and handling • Freely or with carriers

29. The Minerals – An Overview • Bioavailability • Varies • Food binders • Nutrient interactions • Presence of other minerals • Absorption, metabolism, and excretion • Varied roles

30. Sodium • Roles in body • Principal cation of extracellular fluid • Primary regulator of volume • Acid-base balance • Nerve impulse transmission • Muscle contraction • Sodium travels freely in the blood • Kidneys: filter out and return what is needed

31. Sodium • Recommendations • Diets rarely lack sodium • UL for adults • Average intake in U.S. exceeds the UL • Hypertension • Salt vs. sodium or chloride alone • Salt intake • DASH diet

32. Sodium • Bone Loss (osteoporosis) • High salt intake is associated with increased calcium excretion • Potassium as protective factor • DASH diet recommendation • Food sources • Processed foods • More sodium • Less potassium

33. Sodium • Deficiency • Conditions causing a deficiency • Hyponatremia • Toxicity • Acute • Edema and high blood pressure • Chronic • Hypertension

34. Chloride • Essential nutrient • Roles in the body • Major anion of extracellular fluids • Moves passively across membranes • Associates with sodium and potassium • Helps maintain fluid and electrolyte balance • Part of hydrochloric acid

35. Chloride • Recommendations and intakes • Abundant in processed foods • Recommendations are slightly higher, but still equivalent to those of sodium • Deficiency and toxicity • Diets rarely lack chloride • Conditions leading to deficiency • Toxicity – due to water deficiency

36. Potassium • Principal intracellular cation • Roles in the body • Helps maintain fluid and electrolyte balance • Helps maintain cell integrity • Aids in nerve impulse transmission and muscle contraction

37. Potassium • Recommendations and intakes • Fresh foods are richest sources • AI for potassium • Increase fruit and vegetable consumption • Hypertension • Diets low in potassium • Diets high in potassium • Risk of stroke

38. Potassium • Deficiency • Increase in blood pressure • Salt sensitivity • Kidney stones • Bone turnover • Irregular heartbeats • Muscle weakness • Glucose intolerance • Toxicity • No UL • Overconsumption of potassium salts or supplements • Certain diseases or treatments • Kidneys accelerate excretion

39. Calcium • Most abundant mineral in the body • Adequate intake • Grows a healthy skeleton in early life • Helps minimize bone loss in later life • Majority of body’s calcium is in bones and teeth • Part of bone structure • Calcium bank

40. Calcium • In bones • Calcium salts form crystals • Hydroxyapatite • Strength and rigidity to maturing bones • Bone remodeling • In teeth • Fluoride stabilizes calcium crystals in teeth

41. Calcium • In body fluids • Helps to maintain normal blood pressure • Extracellular calcium • Participates in blood clotting • Intracellular calcium • Regulation of muscle contraction • Transmission of nerve impulses • Secretion of hormones • Activation of some enzyme reactions

42. Calcium • Disease prevention • Hypertension • Blood cholesterol • Diabetes • Colon cancer • Obesity • May help maintain healthy body weight • Inverse relationship with food sources

43. Calcium • Calcium balance • Involves system of hormones and vitamin D • Parathyroid hormone & calcitonin • Organ system response • Intestines • Bones • Kidneys • Calcium rigor • Calcium tetany

44. Calcium Balance

45. Calcium • Absorption • Adults absorb about 30% of the calcium ingested • Stomach’s acidity – calcium soluble • Vitamin D – calcium-binding protein • Efficiency and inadequate intakes • Factors that enhance calcium absorption • Factors that inhibit calcium absorption

46. Calcium • Recommendations • Based on amount needed to retain calcium in bones • Peak bone mass • Set high enough to accommodate 30% absorption rate • UL has been established • Adverse effects from supplements

47. Maintaining Blood Calcium

48. Calcium • Milk products • Calcium is most abundant in milk products • Conceal milk products in foods • Consequences of drinking too little milk • Other foods • Bioavailability • Fortified juices and foods • Calcium and iron

49. Bioavailability of Calcium from Selected Foods

50. Cauliflower, watercress, brussels sprouts, rutabaga, kale, mustard greens, bok choy, broccoli, turnip greens ≥ 50% absorbed ≈ 30% absorbed Milk, calcium-fortified soy milk, calcium-set tofu, cheese, yogurt, calcium- fortified foods and beverages ≈ 20% absorbed Almonds, sesame seeds, pinto beans, sweet potatoes ≤ 5% absorbed Spinach, rhubarb, Swiss chard Stepped Art Fig. 12-15, p. 404