Essential Water and Minerals in Human Health

1. Water and Minerals-Chapter 6Metabolism-no readingsEnergy Balance-Chapter 7Nutrition throughout the Lifespan-Chapters 11,12,13

2. Water • Functions of water • Occupies essentially every space within and between body cells • Involved in virtually every body function • Largest single constituent of the human body, averaging 60% of total body weight • Provides shape and structure to cells • Regulates body temperature • Aids in the digestion and absorption of nutrients

3. Water—(cont.) • Functions of water—(cont.) • Transports nutrients and oxygen to cells • Serves as a solvent for vitamins, minerals, glucose, and amino acids • Participates in metabolic reactions • Eliminates waste products • Is a major component of mucus and other lubricating fluids

4. Water—(cont.) • Water balance • Total body water balance is tightly regulated within ±0.2% of body weight. • Sensation of thirst and the action of the hormone vasopressin control our daily fluid balance. • Water output • Adults lose approximately 1750 to 3000 mL of water daily. • If in water balance, water losses must be replaced by consuming fluid in the form of drinks and foods

5. Water—(cont.) • Water intake • Drinking water • Other beverages • Solid foods

6. Water—(cont.) • Water recommendations • Body cannot produce as much water as it needs. • For men ages 19 to older than 70 years, the Adequate Intake (AI) is 3.7 L/day. • For women of the same age, the AI is 2.7 L/day. • Daily intakes below the AI may not be harmful to healthy people.

7. Water—(cont.) • Water recommendations—(cont.) • Fluid intake is assumed to be adequate when the color of urine produced is pale yellow. • Elderly and children • Drinking fluids should not be delayed until the sensation of thirst occurs.

8. Water—(cont.) • Water recommendations—(cont.) • Increases in water loss • Vomiting, diarrhea, and fever • Thermal injuries, fistulas, uncontrolled diabetes, hemorrhage, and certain renal disorders • Use of drainage tubes contributes to increased water losses. • Intake and output records are used to assess adequacy of intake.

9. Water—(cont.) • Alterations in intake • Dehydration is characterized by • Impaired mental function • Impaired motor control • Increased body temperature during exercise • Increased resting heart rate when standing or lying down • Increased risk of life-threatening heat stroke

10. Water—(cont.) • Alterations in intake—(cont.) • A net water loss of as little as 1% of body weight increases plasma osmolality. • A loss of 20% can be life threatening. • Hyponatremia • At risk patients include infants; psychiatric patients with excessive thirst; women who have undergone surgery using a uterine distention medium; and athletes in endurance events who drink too much water, fail to replace lost sodium, or both.

11. Water—(cont.) • Hyponatremia—(cont.) • Symptoms • Lung congestion, muscle weakness, lethargy, and confusion • Can progress to convulsions, prolonged coma, and death

12. MineralsKeys to Understanding Minerals • Major minerals are present in the body in amounts greater than 5 g. • Calcium, phosphorus, magnesium, sulfur, sodium, potassium, and chloride are major minerals. • Iron, iodine, zinc, selenium, copper, manganese, fluoride, chromium, and molybdenum are classified as minor or trace minerals or minor or trace elements (present in body in amounts less than 5 g (iron ~ 5 g). • Both major and minor minerals are essential for life.

13. Keys to Understanding Minerals—(cont.) • General chemistry • Minerals do not undergo digestion, nor are they broken down or rearranged during metabolism. • Minerals are not destroyed by light, air, heat, or acids during food preparation.

14. Keys to Understanding Minerals—(cont.) • General functions • Minerals function to provide structure to body tissues and to regulate body processes. • Mineral balance • Maintained by • Releasing minerals from storage for redistribution • Altering rate of absorption • Altering rate of excretion

15. Keys to Understanding Minerals—(cont.) • Mineral toxicities • Stored minerals can produce toxicity symptoms. • Toxicity related to excessive use of mineral supplements, environmental or industrial exposure, human errors in commercial food processing, or alterations in metabolism • Mineral interactions • Mineral status must be viewed as a function of the total diet.

16. Keys to Understanding Minerals—(cont.) • Sources of minerals • Unrefined or unprocessed foods have more minerals than refined foods. • Major electrolytes • Sodium • Salt (sodium chloride) is approximately 40% sodium. • Wide variations in sodium intake exist between cultures and between individuals within a culture.

17. Keys to Understanding Minerals—(cont.) • Major electrolytes—(cont.) • Sodium—(cont.) • Major extracellular cation • Largely responsible for regulating fluid balance • Almost 98% of all sodium consumed is absorbed. • Adequate Intake for sodium is set at 1500 mg/day for young adults. • One hundred percent of adult men and women exceed the AI of 1500 mg of sodium per day.

18. Keys to Understanding Minerals—(cont.) • Potassium • Major cation of the intracellular fluid • When potassium excretion is impaired, such as secondary to diabetes, chronic renal insufficiency, end- stage renal disease, severe heart failure, and adrenal insufficiency, high potassium intakes can lead to hyperkalemia and life-threatening cardiac arrhythmias. • Chloride • Major anion in the extracellular fluid • AI for younger adults is 2.3 g/day.

19. Major Minerals • Calcium • Most plentiful mineral in the body • Probably protects against colorectal cancer • Calcium balance in the blood is achieved through the action of vitamin D and hormones. • Three daily servings of milk, yogurt, or cheese plus nondairy sources of calcium are needed to ensure an adequate calcium intake. • An adequate calcium intake throughout the first three decades of life is needed to attain peak bone mass as determined by genetics.

20. Major Minerals—(cont.) • Phosphorus • After calcium, the most abundant mineral in the body is phosphorus. • About 60% of natural phosphorus from food sources is absorbed. • Dietary deficiencies of phosphorus do not occur. • Involved in energy yield (ATP) • Magnesium • Fourth most abundant mineral in the body • Co-factor in some enzymes-without Mg these enzymes cannot work

21. Major Minerals—(cont.) • Sulfur • Does not function independently as a nutrient but is a component of biotin, thiamin, and the amino acids methionine and cysteine • There is no RDA or AI for sulfur.

22. Trace Minerals • Impact on health is significant • Too little of a trace mineral can be just as deadly as too much. • Iron • Approximately two-thirds of the body’s iron is contained in the heme portion of hemoglobin. • Iron in foods exists in two forms: heme iron, found in meat, fish, and poultry, and nonheme iron, found in plants such as grains, vegetables, legumes, and nuts. • Overall rate of iron absorption is only 10% to 15% of total intake.

23. Trace Minerals—(cont.) • Iron—(cont.) • Only 1% to 7% of nonheme iron is absorbed from plant foods when they are consumed as a single food. • RDA for iron is set at 8 mg for men and postmenopausal women and at 18 mg for premenopausal women. • Iron deficiency anemia • Microcytic, hypochromic anemia • Pica

24. Trace Minerals—(cont.) • Iron—(cont.) • Potential for toxicity is moderate to high. • Hemochromatosis • Acute iron toxicity • Zinc • A regular and sufficient intake is necessary. • Plays important roles in immune system functioning and in wound healing

25. Trace Minerals—(cont.) • Iodine • Essential component of thyroxine (T4) and triiodothyronine (T3) • Approximately 50% of the population uses iodized salt. • Selenium • A component of a group of enzymes that function as antioxidants • Selenium deficiency is rare in Canada.

26. Trace Minerals—(cont.) • Copper • Distributed in muscles, liver, brain, bones, kidneys, and blood • Involved in hemoglobin synthesis, collagen formation, wound healing, and maintenance of nerve fibers • Manganese • Dietary deficiencies have not been noted. • Co-factor for several enzymes • High manganese intake from drinking water also produces neuromotor deficits similar to Parkinson’s disease.

27. Trace Minerals—(cont.) • Fluoride • Promotes the mineralization of developing tooth enamel prior to tooth eruption and the remineralization of surface enamel in erupted teeth • Fluoridation of municipal water • Chromium • Enhances the action of the hormone insulin to help regulate blood glucose levels • Appears that average intake is adequate

28. Trace Minerals—(cont.) • Molybdenum • Plays a role in red blood cell synthesis • Dietary deficiencies and toxicities are unknown. • Other trace elements • Evidence is difficult to obtain and quantifying human need is even more formidable.

29. Water and Minerals in Health Promotion • Water • Recommended that thirst be the guide to consuming adequate fluid; specific amounts or types of beverages to satisfy fluid need are not suggested • For healthy people, hydration is unconsciously maintained with ad libitum access to water. • Sodium and potassium • Recommendations • Less sodium • More potassium

30. Metabolism

31. METABOLISM IN GENERAL AND VITAMINS IN METABOLISM

32. METABOLISM IN GENERAL AND MINERALS IN METABOLISM

33. Energy BalanceChapter 7

34. Energy Intake • Calories come from carbohydrates, protein, fat, and alcohol. • The total number of calories in a food or diet can be estimated by multiplying total grams of carbohydrates, protein, or fat by the appropriate number of calories per gram.

35. Energy Expenditure • Basal metabolism • Caloric cost of staying alive or the amount of calories required to fuel the involuntary activities of the body at rest after a 12-hour fast • Basal metabolic rate (BMR) accounts for approximately 60% of total calories expended. • The less active a person is, the greater the proportion of calories used for basal energy expenditure (BEE).

36. Energy Expenditure—(cont.) • Basal metabolism—(cont.) • Lean tissue (muscle mass) contributes to a higher metabolic rate than fat tissue. • Loss of lean tissue that usually occurs with aging beginning sometime around age 30 is one reason why calorie requirements decrease as people get older.

37. Energy Expenditure—(cont.) • Physical activity • Accounts for approximately 30% of total calories used

38. Calories In Versus Calories Out • State of energy balance is the relationship between the amount of calories consumed and the amount of calories expended. • A “positive” energy balance occurs when calorie intake exceeds calorie output. • A “negative” calorie balance occurs when calorie output exceeds intake.

39. What Is “Normal” Weight • “Normal” or “desirable” weight is that which is statistically correlated to good health. • Three criteria used for assessing overweight and obesity • Body mass index (BMI) • Waist circumference • Existing health problems

40. What Is “Normal” Weight—(cont.) • Body mass index • Body mass index (BMI) has replaced traditional weight–height calculations that were used to determine “ideal” or “desirable” body weight. • Formula to calculate BMI is weight in kilograms divided by height in meters squared. • Drawback • Does not take body composition or body fat distribution into account • Skinfold measurements and bioelectrical impedance can assess body composition, but neither technique is widely used.

41. What Is “Normal” Weight—(cont.) • Waist circumference • Location of excess body fat is a more important and reliable indicator of disease risk. • Storing a disproportionate amount of total body fat in the abdomen increases risks for type 2 diabetes, dyslipidemia, hypertension, and cardiovascular disease. • Abdominal fat is clinically defined as a waist circumference as per next slide

42. What Is “Normal” Weight—(cont.)

43. What Is “Normal” Weight—(cont.) • Existing health problems • Presence of existing health problems impacts a person’s absolute risk related to weight. • Generally, the number and severity of comorbid conditions increases with increasing levels of obesity.

44. Energy Balance in Health Promotion • Preventing or reducing overweight is achieved by adopting a lifestyle approach that includes healthier food choices, increasing physical activity, and behavior modification.

45. Energy Balance in Health Promotion—(cont.) • Healthier choices • Encompasses a two-pronged approach • Eating less of certain items • Eating more of others • Emphasis is on healthy and wholesome choices. • Remember fat-free foods still contain calories from protein and carbohydrates. • Reducing alcohol intake is another way to consume fewer calories.

46. Energy Balance in Health Promotion—(cont.) • Portion control • Portion sizes have grown over the last 20 years. • “Portion distortion” appears to be a widespread problem. • Change the environment • Food should be less accessible, less visible, and proportioned in smaller quantities.

47. Energy Balance in Health Promotion—(cont.) • Physical activity • Benefits of increasing activity are dose dependent and occur along a continuum. • Yet we sit down and we chow down and we continue as a population to increase waist circumferences. • Minimum of 150 minutes per week of moderate-intensity to vigourous physical activity helps to control waist circumferences when combined with the six dietary principles

48. How to Burn 150 Calories (Based on a 150-Pound Person) • Pedal a stationary bicycle for 20 minutes. • Practice fast dance steps for 24 minutes. • Work in the garden for 27 minutes. • Walk briskly (6 km/hour) for 33 minutes. • Clean the house for 38 minutes.

49. Suggestions for Increasing Activity • Find something enjoyable. • Use the buddy system. • Spread activity over the entire day if desired. • Start slowly and gradually increase activity. • Move more. • Keep an activity log.

50. Nutrition for Infants, Children, and AdolescentsChapter 12