Water and Major Minerals

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Water

• Intracellular Fluid– 2/3 of the body’s water

• Extracellular Fluid– Interstitial and Intravascular

• Body fluid also contains– Solutes

• E.g., Electrolytes: Cations and Anions

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Maintenance of Intracellular and Extracellular Fluid Balance

• Transmembrane pumps– Sodium, Potassium moved against concentration

gradient• Osmosis

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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

– urea7

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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

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Overview of Minerals• Major versus Trace Minerals• Food Sources• Functions• Deficiencies

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

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Sodium (Na+)

• Foods– Grains, processed foods, soups and sauces

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

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Sodium (Na+)• 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

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Potassium (K+)

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

grains• Needs

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

Potassium (K+)• 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

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Chloride (Cl-)• Foods

– Salt (NaCl)• Needs

– AI: 2,300mg• Functions

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

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

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Calcium (Ca++)• Foods

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

• Needs– RDA: 1,000mg to 1,200mg, 1,300mg in adolescents– DV: 1,000mg– U.S. intake is 720mg to 1,195mg (lower in women)– Calcium supplements– Blood calcium levels regulated tightly

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Functions of Calcium (Ca++)

• 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

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Calcium (Ca++)

• Potential health benefits of calcium– Colon cancer prevention– Protects against formation of oxalate kidney

stones– Blood pressure effect

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

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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

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Phosphorus• Foods

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

– RDA: 700mg– DV: 1,000mg– Average intake is 950 mg to 1650 mg/day

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Phosphorus• Functions

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

• Part of ATP– Role in hypertension prevention

• Deficiency– Rare but a chronic deficiency contributes to bone

loss, decreased growth and poor tooth development

• Toxicity and Upper Level– UL: 3-4 grams/day

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Magnesium (Mg++)• Foods

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

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

• Increases 10-20mg over age 30– DV: 400mg– Fewer than 25% of US adults meet RDA

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Magnesium (Mg++)

• Functions– Vital role in range of biochemical and physiological

processes• Deficiency

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

• Upper Level– 350mg from supplements and nonfood items only