Chapter 9 - Water & Minerals

Chapter 9: Water & Minerals Water and body fluids 60% of adult body's weight Carries nutrients and waste, structure of large molecules, metabolic reactions, solvent, blood volume Aids in normal body temperature regulation, acts as lubricant and cushion Water Intake Water intake regulation Hypothalamus: initiates drinking Water imbalances: Dehydration, Water intoxication, hyponatremia Water excretion regulation: Brain & kidneys, Renin & aldosterone Water Recommendations & Sources Minimum water needs Excretion: 500 ml per day Men's intake: 3.7 L Women's intake: 2.7 L Potassium Principle (+) ion inside the cell Maintains fluid & electrolytes balance Enabled in fluid & electrolyte balance Deficiency symptoms: Low blood pressure, kidney stones Toxicity: Rare consumption of K salts, supplements Hypertension: Low intake may lead to low potassium Food sources: Fruits & vegetables Fluids, Electrolytes & Acid-Base Balance Electrolyte solutions: ions of a salt in water Closely regulated electrolyte balance: Kidneys regulate sodium and water Acid-base balance Electrolyte mixtures act as buffers Kidneys play primary role in maintaining acid-base balance Calcium Most abundant mineral in the human body Bone structure, blood clotting, muscle contraction Transport of ions across membranes, maintains blood pressure Secretion of substances, activates certain enzymes Balance When blood calcium is low, it is deposited into bone Regulating system to counter low blood calcium Small intestine absorption, bones release Ca, kidneys Osteoporosis Women may lose 20% of bone mass after menopause Prevented with adequate intake, weight-bearing activity Recommendations RDA (Recommended Dietary Allowance) Increased again for women Sodium Principle electrolyte in extracellular fluid Primary regulator of the extracellular fluid volume Recommendation Adults: 2300 mg/day Average US intake: 3400 mg/day Blood pressure Hypertension Chloride Major ion in the extracellular fluids, maintains fluids Part of hydrochloric acid in gastric fluid Major sources: Salt Calcium Rich Foods Milk products, fortified foods, some vegetables, leafy greens Phosphorus Second most abundant mineral in the body Required by 300+ enzymes Found in bones, teeth, and all body tissue Assists in DNA and RNA proper function Best Sources: Animal protein, milk, cheese Deficiency (rare) Rickets in children, osteomalacia in adults Magnesium Found in bones, muscles, heart, liver, soft tissues Enzymes, energy release, muscle function Deficiency Symptoms Low blood Ca levels, muscle cramps, fatigue Toxicity is rare but fatal Caused by high doses of Mg salts Sources Dark green leafy vegetables, nuts, legumes, whole grains, fortified foods, chocolate Selenium Antioxidant Assists in synthesizing thyroid hormones Cancer protective against prostate, colon, and other cancers Deficiency Predisposed to Keshan disease Fatigue, skin, vomiting, diarrhea, muscle/hair loss, bone pain Toxicity Can cause vomiting, diarrhea, hair/nail loss, lesions Sources Seafood, meat, poultry, eggs Iodine Part of the thyroid hormone Regulates body temp, metabolic rate, blood cell production Deficiency Goiter: enlargement of thyroid gland Hypothyroidism, cretinism Toxicity Enlargement of thyroid gland Sources Seafood, iodized salt, dairy RDA: 150 micrograms The Trace Minerals Iron Component in hemoglobin, myoglobin Assists in oxygen delivery Most common nutrient deficiency Causes of iron deficiency Inadequate dietary intake, blood loss Hemochromatosis Hereditary defect in absorption Recommendations Men: 10 mg/day Women (non-child bearing years): 18 mg/day Food sources Heme iron: meat, poultry, fish Non-heme iron: beans, grains, fruits, vegetables Zinc Required by 300 enzymes Maintains blood sugar, transport insulin Albumin Deficiency Poor growth, vegetarians Toxicity Produces copper deficiency anemia Sources Found in high protein animal foods Copper Enzymes, energy release, muscle function Produces copper deficiency anemia Deficiency symptoms Low blood cell count, muscle cramps, fatigue Toxicity is rare but fatal Caused by high doses of Cu salts Sources Found in high protein animal foods