PUBH 1517 - (Chapter 8) Water and Minerals

PUBH 1517 - (Chapter 8) Water and Minerals - Nutrition...

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Unformatted text preview: Nutrition: Concepts and Nutrition: Concepts and Controversies, 8 ed Chapter 8 Water and Minerals Water Functions in the Body Water Functions in the Body • • • • • • • Solvent Transport vehicle for nutrients Cleansing agent Essential in chemical reactions Lubricant Shock absorber Heat­regulator Water Balance Water Needs Water Needs • Many factors affect need (see p. 266) due to • increasing losses Average need for adults: • 1 to 1.5 ml per day per calorie spent (2 to 3 liters or quarts for 2000 calories) • This includes ALL sources of fluids (food & beverages – see p. 268) • Thirst lags behind the deficit, indicating loss of up to 2 cups of body’s fluid Dehydration Dehydration • Mild (<5% weight loss): weakness, low energy, • • • rapid pulse, dry mouth, impaired kidney function, reduced urine quantity Severe (>5% wt. loss): Confusion, disorientation, bluish lips, rapid breathing & pulse Body stops “wasting” water in sweat, causing temperature to rise We can only survive a few days without water Water Supply Water Supply Law requires • yearly statement from public utilities to customers naming chemicals & bacteria in local water • 24 hour notification of discovery of dangerous contaminants FDA regulates bottled water, requiring yearly testing to ensure same standards as tap water (for purity & sanitation) Chlorine in Water Chlorine in Water • Purpose • Statistical correlation found between • consumption of chlorinated water & increase in likelihood of developing colon & other cancers Estimated 25,000 deaths each day worldwide from diseases caused by organisms carried in water (without chlorination) Bottled Water Bottled Water • All water comes from either surface or ground sources, and is subject to contamination • Read label on bottle to check source, type (see p. 271 for terms on labels) • Water coolers can become contaminated with bacteria & mold growth if not cleaned regularly Other Minerals in Water Other Minerals in Water • Hard water • Soft water – More easily dissolves cadmium & lead (toxic metals) from older pipes • Precaution with older pipes: let water run for a minute in the morning to flush out harmful minerals Body Fluids & Minerals Body Fluids & Minerals Terms Terms • Salts: compounds composed of charged • • particles, such as sodium chloride or potassium chloride Electrolytes: electrically charged ions formed when mineral salts dissolve in water Fluid & electrolyte imbalance: failure to maintain the proper amt & kind of fluid in every body compartment (a medical emergency) Some Roles of Minerals Some Roles of Minerals • Acid­Base Balance – Some mineral salts serve as buffers to help maintain constant pH • Fluid & Electrolyte Balance How Electrolytes Govern Water Flow ...
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