Water and Major Minerals

Chapter 14

2

3

4

Functions of Water• Maintenance of blood volume• Transport of nutrients and oxygen• Fluid synthesis• Lubricant in knees and joints• Solvent in metabolic processes• Temperature Regulation

– Specific Heat• Waste Product Removal

– urea5

6

Water Sources & Needs• Water in Foods

– Sweetened beverages provide little satiety and few micronutrients

• Needs– Vary with body size, physical activity, environmental

conditions and dietary intake– AI: 15 cups adult men, 11 cups adult women– Based on 80% fluid intake, 20% food intake– Needs met when intake = output

7

Regulation of Water Balance• Small losses are compensated for • Body’s response to loss of water

– Anti-diuretic hormone (ADH)– Renin-angiotensin system– Aldosterone

• Dehydration– signs

• Water Toxicity– Hyponatremia

8

11

12

13

14

15

Minerals in Foods• Both plants and animal

sources• Bioavailability

– Body adjusts mineral absorption to our needs

– Megadosing can alter absorption of other minerals

– Fiber affects absorption

17

Overview of Minerals• Major versus Trace Minerals• Food Sources• Absorption, Transport, and Excretion

– Bioavailability– Phytic acid, oxalic acid, polyphenols– Role of gastric acidity

• Functions• Deficiencies

– Calcium, potassium, magnesium , iron, zinc, and iodine• Toxicity

18

Sodium

• Foods– Grains, processed foods, soups and sauces

• Needs– AI: 1,500mg (under age 51)– DV: 2,400mg

• Absorption, Transportation, Storage, and Excretion

19

Sodium (2)• Functions

– Absorption of glucose and some amino acids– Normal muscle and nerve function– Water balance

• Deficiency– Rare (hyponatremia)– Excessive perspiration, diarrhea, vomiting

• Excess and Upper Level– UL: 2,300mg

20

21

Potassium

• Foods– Unprocessed foods: fruits, vegetables, milk, whole

grains• Needs

– AI: 4,700mg– DV: 3,500mg– Typical US adult intake falls below both

• Absorption, Transportation , Storage, and Excretion

22

Potassium (2)• Functions

– Major cation inside cells– High intake suppresses renin-angiotensis system and

promotes excretion of sodium• Deficiency

– Hypokalemia (life-threatening)– Depletion by some diuretics

• Excess and Upper Level– Hyperkalemia (also life-threatening)– In poor kidney function– No UL set

23

24

Chloride• Foods

– Salt (NaCl)• Needs

– AI: 2,300mg• Absorption, Transportation, Storage, and

Excretion• Functions

– Main anion in extracellular fluid– Nerve impulse transmission, HCl, immune response,

acid-base balance• Deficiency• UL: 3,600mg

Major Minerals and Health• Hypertension: high blood pressure

– Increases risk for heart disease, stroke, and kidney disease

– Risk factors for hypertension:• Obesity• High sodium intake• Lack of physical activity• Excess alcohol intake• Race• Age• Family history

Sodium• Dietary recommendations

– Daily intake less than 2,300 mg/d– Daily intake less than 1,500 mg/d for persons

51 and older– Limit consumption of foods that contain refined

grains, especially those that contain solid fats, added sugars, and sodium

30

31

32

33

Calcium

• Foods– Dairy, fortified foods, green leafy vegetables– Bioavailability issues

• Needs– RDA: 1,000mg to 1,200mg, 1,300mg in adolescents– U.S. intake is 720mg to 1,195mg – Calcium supplements

• Absorption, Transportation, Storage, and Excretion– Blood calcium levels regulated tightly

34

35

36

37

Functions of Calcium

• Bone development and maintenance– Cortical and trabecular bone– Bone remodeling– Osteoblasts, osteocytes and osteoclasts

• Blood clotting• Transmission of nerve impulses to target cells

– Tetany• Muscle contraction• Cell metabolism

– Calmodulin system

38

Calcium

• Functions– Bone structure

• Hydroxyapatite• Bone cells

– Osteoblasts– Osteoclasts

• Reserve of calcium and phosphorus

41

42

43

Calcium• Potential health benefits of calcium

– Colon cancer prevention– Protects against formation of oxalate kidney stones– Blood pressure

• Upper Level– 2500mg– Hypercalcemia can lead to kidney stones

Risk Factors You Cannot Change Gender. Women have less bone tissue and lose bone faster than men because of the changes that happen with menopause.Age. The older you are, the greater your risk of osteoporosis. Your bones become thinner and weaker as you age.Body size. Small, thin-boned women are at greater risk for developing osteoporosis than larger women.Ethnicity. Caucasian and Asian women are at the highest risk of developing the disease. African-American and Hispanic women have a lower, but still significant, risk.Family history. Your risk for fractures may be due, in part, to heredity. People whose parents have a history of fractures also seem to have reduced bone mass and may be at risk for fractures themselves.

Risk Factors You Can Change Sex hormones. Abnormal absence of menstrual periods (amenorrhea), low estrogen levels (menopause), and low testosterone levels in men .Anorexia nervosa. Characterized by an irrational fear of weight gain, this eating disorder increases your risk for osteoporosis.Calcium and vitamin D intake. A lifetime diet low in calcium and vitamin D makes you more prone to bone loss.Medication use. Long-term use of glucocorticoids and some anticonvulsants can lead to loss of bone density.Lifestyle. An inactive lifestyle or extended bed rest weakens bone.Cigarette smoking. Cigarettes are bad for the bones as well as the heart and lungs.Alcohol intake. Excessive consumption of alcohol increases the risk of bone loss and fractures.

46

Osteoporosis• Bone Loss

– Normal/low bone mass: osteopenia– Very low bone mass: osteoporosis– Kyphosis (Dowager’s hump)

• Diagnosis– DEXA bone scan

• Prevention– Bone building nutrients– Active lifestyle with weight-bearing activities– Not smoking– Drug therapy

47

48

49

50

51

Phosphorus• Foods

– Milk, cheese, meat, bakery products, and cereals• Functions

– Major component of bone and teeth– Critical to the function of every body cell

• Part of ATP

• Deficiency– Rare but a chronic def contributes to bone loss,

decreased growth and poor tooth development

52

Magnesium• Foods

– Part of chlorophyll – plant products– Smaller amounts from hard water, milk, and meat

• Needs– RDA: 400mg men, 310mg women (19-30)

• Increases 10-20mg over age 30

– Fewer than 25% of US adults meet RDA• Deficiency

– Irregular heartbeat, weakness, muscle spasms– Increases risk of osteoporosis

53

54

Sulfur

• Needs– No AI or UL set

• Functions– Synthesis of sulfur-containing compounds– Stabilizes the structure of proteins– Participates in acid-base balance

• No deficiency or toxicity