Water And The Major Minerals Copyright 2005 Wadsworth Group, a division of Thomson Learning.

Water And The Major Minerals

Copyright 2005 Wadsworth Group, a division of Thomson LearningCopyright 2005 Wadsworth Group, a division of Thomson Learning

Water And The Body Fluids

• Functions of water:– Transport– Structural support for molecules– Participates in metabolic reactions– Solvent– Lubricant– Body temperature regulation– Maintains blood volume



• Water balance and recommended intakes– Intracellular fluid– Extracellular fluid

•Interstitial fluid


One Cell And Its

Associated Fluids


Water And The Body Fluids• Water balance and recommended

intakes– Water intake

•Thirst•Dehydration•Water intoxication



• Water balance and recommended intakes– Water sources– Even water sources with caffeine



Water Sources, Losses and Recommendations

• A camel can go for some time without water because it generates metabolic water by respiration of the fat in its hump but only for a short time. It will drink water as soon as it can.

• For humans metabolic water is not enough for maintaining fluid balance even for a short time

• You can get water from foods but then you will also get a lot of calories

• So we have to get our water from liquids ideally just plain water

Other loss methods – vomitting or diarrhea

Health Effects of water• Water balance and recommended intakes

– Water recommendations• Based on diet, activity, environmental temperature, body temperature,

humidity

• For a person who expends 2000 kcalories per day– 2 to 3 liters of water i.e. about 7 to 11 cups

– Health effects of water• Hard water

– Calcium, Magnesium

– Better for drinking if you have heart disease or hypertension

• Soft water – Sodium or Potassium

– Better for household use (Lathering)

• Bottled water

• More on Water in Chapter 13

Blood Volume and Blood Pressure

• ADH (Antidiuretic hormone) and Water retention

• Renin and Sodium retention

• Angiotensin and Blood vessel constriction

• Aldosterone and sodium retention

Too little water• Too little water in the blood, detected by the

hypothalamus. • More ADH produced by the pituitary gland.• More water reabsorbed by the kidneys, caused by

ADH. • Blood becomes less concentrated. • Negative feedback; hypothalamus detects change

in blood concentration. • Pituitary produces less ADH. • Blood returns to correct osmotic concentration.

Too much water

• Too much water in the blood, detected by the hypothalamus.

• Less ADH produced by the pituitary gland. • Less water reabsorbed by the kidneys, caused by

ADH. • Blood becomes more concentrated. • Negative feedback; hypothalamus detects change

in blood concentration. • Pituitary produces more ADH. • Blood returns to correct osmotic concentration.


How The Body Regulates Blood Volume and therefore blood pressure

Fluid And Electrolyte Balance

• Dissociation of salt in water– Ions

•Cations – positively charged•Anions – negatively charged

– Electrolyte solution•Pure water is a poor conductor of

electricity•But ions dissolved in water will conduct

electricity •Hence salts dissolved in water are called

electrolytes



• Electrolytes attract water– Water has weak positive and negative

charges

• Water follows electrolytes– Solutes– Osmosis– Osmotic pressure



Water Dissolves SaltsAnd Follows Electrolytes

Fluid And Electrolyte Balance• Electrolytes that are predominantly inside

cells– Potassium, Magnesium, Phosphate and

Sulfate• Electrolytes that are predominantly outside

cells– Sodium and Chloride

• Cell membrane are selectively permeable

• Water follows electrolytes– Solutes– Osmosis– Osmotic pressure


Fluid And Electrolyte Balance• Water follows electrolytes

– Solutes•Salts, proteins etc that are dissolved in

water or fluid– Osmosis

•Movement of water from areas of lower concentration of solutes to areas of higher concentration of solutes

– Osmotic pressure•Amount of pressure needed to prevent

osmosis across a membrane


• Vegetables “sweat” when sprinkled with salt

• Raisins plump up when immersed in water

Fluid And Electrolyte Balance• Proteins regulate flow of fluids and

ions– Edema– Transport proteins e.g. Sodium Potassium

pumps (remove sodium actively from the cell)

• Regulation of fluid and electrolyte balance happens by controlling– The amount of minerals absorbed or

reabsorbed in the GI tract– The amount of minerals excreted or

reabsorbed by the kidneys


• Sodium and chloride most easily lost– Sweating, bleeding, excretion

• Different solutes lost by different routes– Vomiting or diarrhea: Sodium– Aldosterone over production (tumor):

Potassium (from kidneys)– Uncontrolled diabetes: Glucose– With serious losses like this medical

intervention is necessary



Fluid And Electrolyte Imbalance

• Replacing lost fluids and electrolytes– Oral

rehydration therapy (ORT)



Acid-Base

Balance

pH

Acid-Base Balance

• Remember that a buffer is a mixture of a weak acid and its conjugate base or a weak base and its conjugate acid.

• Regulation by the buffers in body fluids– Bicarbonate (Base)– Carbonic acid (Weak Acid)– Some proteins (Remember proteins

can act as both base and acid)


Acid-Base Balance

• Regulation by the lungs– CO2 formed by cells during respiration

dissolves in blood to form carbonic acid which dissociated to form H+ and bicarbonate

– Too much acid ->respiration speeds up -> more CO2 is exhaled

– Too much bicarbonate -> respiration slows down -> increases the amount of dissolved CO2 i.e. carbonic acid


Acid-Base Balance

• Regulation by the kidneys– The kidneys have two important roles in

the maintaining of the acid-base balance: • reabsorb bicarbonate from urine

• excrete hydrogen ions into urine

– The acidity of urine changes to ensure that the body’s total acid-base balance stays the same.


The Minerals - An Overview

The Minerals - An Overview• Inorganic elements

– Not easily destroyed or modified– Can only be lost by leaching into water

• The body’s handling of minerals– Minerals like Potassium easily absorbed– Minerals like Calcium act more like fat soluble

vitamins and need carriers• Variable bioavailability

– Binders (combine with minerals preventing or reducing absorption)•Phytates (e.g. in Legumes and grains)•Oxalates (e.g. in rhubarb and spinach)


The Minerals - An Overview

• Nutrient interactions

– Similar to the interactions of Vitamins

• Varied roles – Fluid balance – Sodium, Chloride

and Potassium – Bone growth and health – Calcium,

Phosphorous and Magnesium


Sodium• Roles in the body

– Principal extracellular cation– Regulates extracellular volume– Assists in nerve impulse transmission and

muscle contraction• You never really need to add Sodium to food

(there is always enough in foods naturally)• The kidneys remove all the Sodium and only

return what is needed to the blood• When there is too much Sodium in the body,

thirst is induced to increase water intake


Sodium• Hypertension

– Salt sensitivity• People whose parents have high blood

pressure• People with kidney disease or diabetes• African Americans• People over 50

• Osteoporosis– High Sodium intake -> loss of calcium– Effects on Bone density is unknown– Reducing Sodium causes no harm but may

be good• Foods

– Natural foods are good in two ways• They have low Sodium• They have high Potasium• Both of which are associated with better blood pressure regulation


Sodium


More Sodium in ½ cup instant chocolate pudding than in 1 ounce of salted peanuts

Sodium• Deficiency symptoms

– Muscle cramps, mental apathy, loss of appetite

• Toxicity symptoms– Edema, acute hypertension

• Significant source– Table salt, soy sauce– Moderate amounts in meats, milks,

breads, and vegetables– Large amounts in processed foods


Chloride• Chlorine (Cl2) vs. chloride ion (Cl-)

• Roles in body– Principal extracellular anion– Maintains normal fluid and electrolyte

balance– Part of hydrochloric acid found in the

stomach, necessary for proper digestion


Chloride: In Summary• Deficiency symptoms

– Do not occur under normal circumstances

• Toxicity symptom– Vomiting

• Significant sources– Table salt, soy sauce– Moderate amounts in meats, milks,

eggs– Large amounts in processed foods


Potassium• Roles in body

– Principal intracellular cation– Maintains normal fluid and electrolyte

balance– Facilitates many reactions– Supports cell integrity– Assists in nerve impulse transmission

and muscle contractions


Potassium: In Summary• Deficiency symptoms

– Muscular weakness– Paralysis– Confusion

• Toxicity symptoms– Muscular weakness– Vomiting– If given into a vein, can stop the heart


Potassium: In Summary

• Significant sources– All whole foods– Meats, milks,

fruits, vegetables, grains, legumes


Phosphorus

• Chief functions in the body– Mineralization of bones and teeth– Part of every cell– Important in genetic material,

part of phospholipids– Used in energy transfer and in

buffer systems that maintain acid-base balance


Phosphorus• Deficiency symptoms

– Muscular weakness, bone pain• Toxicity symptoms

– Calcification of nonskeletal tissues, particularly the kidneys

• Significant sources– All animal tissues (meat, fish,

poultry, eggs, milk)


Magnesium• Chief functions in the body

– Bone mineralization, building of protein, enzyme action, normal muscle contraction, nerve impulse transmission, maintenance of teeth, and functioning of immune system


Magnesium

• Deficiency symptoms– Weakness– Confusion– If extreme, convulsions, bizarre

muscle movements (especially of eye and face muscles), hallucinations, and difficulty in swallowing

– In children, growth failure


Magnesium• Toxicity symptoms

– From nonfood sources only– Diarrhea, alkalosis, dehydration

• Significant sources– Nuts, legumes– Whole grains– Dark green vegetables– Seafood– Chocolate, cocoa


Sulfur• Roles

– Not used as a nutrient– Present in amino acids Cysteine and

Methionine– In B Vitamin, Thiamin– No deficiencies are known


Calcium And Osteoporosis

• Will be done with Chapter 13


Water And The Major Minerals Copyright 2005 Wadsworth Group, a division of Thomson Learning.

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Transcript of Water And The Major Minerals Copyright 2005 Wadsworth Group, a division of Thomson Learning.