CHAPTER 14

WATER AND MAJOR MINERALS

LEARNING OUTCOMES

• What influences water balance and how does the body maintain water balance?• How does both dehydration and water

intoxication develop? Who gets it? • For water and all major minerals discussed in

class know the food sources, major functions, and the problems with low and high intakes of major minerals and how to avoid inadequate or excessive intakes.• Know the major causes, risk factors, and

treatment options for hypertension and osteoporosis

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WATER

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

water

• Extracellular Fluid• Interstitial and

Intravascular

• Water content varies by age and body composition

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WATER

• Body fluid also contains• Solutes• Electrolytes: Cations and Anions

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WATER BALANCE: SODIUM POTASSIUM PUMP

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WATER BALANCE: SODIUM POTASSIUM PUMP

• Three sodium ions from inside the cell first bind to the transport protein.

• Then a phosphate group is transferred from ATP to the transport protein causing it to change shape and release the sodium ions outside the cell.

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WATER BALANCE: SODIUM POTASSIUM PUMP

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Then a phosphate group is transferred from ATP to the transport protein causing it to change shape and release the sodium

ions outside the cell.

Two potassium ions from outside the cell then bind to the transport protein.

As the phosphate is removed, the protein assumes its original shape and releases the potassium

ions inside the cell.

FUNCTIONS OF WATER

• Functions of Water• Maintenance of blood volume and

transport of nutrients and oxygen• Saliva, bile, amniotic fluid• Lubrication• Temperature Regulation• Specific Heat

• Waste Product Removal

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WATER

•Water is from drinks, food, and metabolism• Beverage choices can add extra kcal

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WATER CONTENT OF SELECT FOODS

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WATER

•Needs• Vary with body size, physical activity,

environmental conditions and dietary intake• AI 15 cups daily adult male, 11 cups

daily adult female• Based on 80% fluid intake, 20% food

intake

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WATER

•Deficiency• Dehydration: fluid output exceeds fluid

intake• Diarrhea, vomit, fever, exercise, hot/dry

weather, high altitude• ~2.5- 3 cups water recommended per

pound of weight loss during exercise

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BODY’S RESPONSE TO DEHYDRATION

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BODY’S RESPONSE TO DEHYDRATION

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WATER TOXICITY

• Toxicity• Hyponatremia• Electrolytes in blood are too

concentrated• Side effects: headache, blurred vision,

cramps, convulsions, death• Who?• Infants, endurance athletes

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Your 4 year old cousin doesn’t like to drink water or milk. He is also considered overweight. What would be a good strategy to ensure he gets enough fluid?

•Soda•Milk shakes•Fruit•Fruit punch

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CASE STUDY

OVERVIEW OF MINERALS

• Major versus Trace Minerals• Absorption• Physiological need• Bioavailability• Competition with other minerals• Competition with non minerals• Oxalate• Polyphenols• Enhancement

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MINERALS IN OUR BODY

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OVERVIEW OF MINERALS

• Function• Water balance (sodium, potassium, calcium, and

phosphorus)• Transmit nerve impulses (sodium, potassium,

calcium)• Enzyme cofactors• Component of body compounds• Body growth

• Deficiency• Calcium, potassium, magnesium iron, zinc, and

iodine• UL

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SODIUM

• Foods• Sodium chloride (40% sodium and 60%

chloride)• 75-80% of our salt intake is from

processed foods

•Needs• AI for under age 51 is 1500 mg, for 51-70

it is 1300 mg, for 70+ it is 1200 mg• UL is 2300 mg

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SODIUM CONTENT OF SELECTED FOODS

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SODIUM

• Absorption via active transport in small and large intestine (sodium potassium pump)• Excretion by the kidneys• Function:• Help absorb glucose and some amino acids in

small intestine• Normal muscle and nerve function• Aids in water balance

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SODIUM

•Deficiency• Rare

•UL• 2300 mg• Hypertension, heart disease, and stroke• Increased calcium loss in urine

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HYPERTENSION

• Causes• Risk factors• Minerals and phytochemicals• Drug therapy• DASH diet• Lifestyle modifications for prevention and

treatment

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BLOOD PRESSURE

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TO LOWER BLOOD PRESSURE

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DASH DIET

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WHO IS MOST LIKELY TO GO OVER THE UL FOR SODIUM?

• There is no UL for sodium• A person who loves fruit• A person who loves cheese• A person who loves diet soda

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POTASSIUM

• Foods (beans, potato, dairy, fruits, vegetables)• Needs• AI is 4700 mg• Average intake below this

• Function: intercellular cation so same functions as sodium except that it decreases calcium excretion• Deficiency• Hypokalemia (low blood potassium) can lead to irregular

heartbeat (usually from urinary losses)• Increased risk of hypertension

• UL• Hyperkalemia (high blood potassium) with poor kidney

function

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POTASSIUM CONTENT OF SELECT FOODS

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CHLORIDE

• Foods- sodium chloride• Needs• AI 2300 mg (based on 40:60 ratio)

• Function• Anion (-) maintains fluid balance• Transmit nerve impulses, part of HCl

• Deficiency rare• UL is 3.6 grams/day

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CALCIUM

• Foods• Dairy, fortified foods, green leafy

vegetables• Needs• AI 1,000 mg to 1,200 mg• U.S. intake 670 mg to 1,100 mg

• UL• 2500 mg day (stones and calcification of organs)• Who?

• Hyperparathyroidism and supplemental calcium

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CALCIUM ABSORPTION

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CALCIUM SUPPLEMENTS

• Calcium carbonate and calcium citrate• Who should take which?• When should you take it?• How much should you take?

• Interactions• Zinc, iron, and magnesium

• Contamination

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CALCIUM

• Absorption• Slightly more efficient in upper SI (more acidic)• Things that influence absorption:• Food source• Vitamin D needed• Efficiency increases during times of need• Full stomach• Age• Fiber, oxalate, phosphorus, polyphenols (tea)

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BLOOD CALCIUM LEVELS ARE KEPT UNDER TIGHT CONTROL

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WHICH OF THESE INCREASES CALCIUM ABSORPTION?

• Taking calcium supplements with a glass of milk• Taking calcium supplements with salty

foods• Taking calcium supplements on an empty

stomach• Spreading out your calcium intake

throughout the day

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CALCIUM FUNCTIONS: BONE HEALTH

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CALCIUM FUNCTION: NERVE TRANSMISSION

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OSTEOPOROSIS

•Bone Loss– Normal/low bone mass-osteopenia– Very low bone mass-osteoporosis

•Diagnosis– DEXA bone scan

•Prevention and Treatment– Bone building nutrients– Active lifestyle– Drug therapy

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PHOSPHORUS

• Foods• Milk, cheese, meat, bakery products and

cereals

•Needs• RDA 700 mg/day• Average intake 950 mg to 1650 mg/day

• Absorption: active transport and diffusion

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PHOSPHORUS

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

(intercellular anion, part of ATP and DNA, part of cell membranes, part of many cellular message systems)

• Deficiency• Rare but a chronic deficiency=bone loss, decreased

growth and poor tooth development• Preterm infants, alcoholics, diarrhea, over use of

aluminum containing antacids• UL• 3-4 grams/day to avoid high blood concentrations

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MAGNESIUM

• Foods• Fruits and vegetables, nuts, coffee, milk and

meats

• Needs• RDA 310-400 mg/day • RDA increases by 10-20 mg/day over age 30• U.S. average 80% RDA

• Absorption: active transport and diffusion, depends on intake, regulated by kidney

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MAGNESIUM

• Functions• Vital role in range of biochemical and

physiological processes• Helps ATP binding• Pumps sodium out of cells and potassium in• DNA and RNA synthesis• Muscle contraction• Insulin• Blood pressure

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MAGNESIUM

• Deficiency• Who?: Excessive losses via urine or GI disorders• Irregular heartbeat, weakness, muscle spasms• Increased risk of osteoporosis

• UL• 350 mg/day• Supplements and nonfood items (antacids and

laxatives)• Kidney failure (elderly)• Weakness, nausea, coma, death

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SULFUR

• Needs• No AI or UL set• Found in sulfur containing amino acids

• Function• Synthesis of sulfur containing compounds• Stabilize the structure of protein• Participates in acid-base balance

• No deficiency or toxicity

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