NUTR 202 1nd Edition Lecture 15 Ch 8 Water 60% of body weight Individuals vary in the amount of water they carry because: age gender amt of fat amt of muscle  Water balanced among fluid compartments ~ 2/3 intracellular fluids ~1/3 extracellular  Interstitial fluids (btw cells)  Intravascular fluids (Plasma) Electrolytes: Na, cl-, and K+ Minerals that help maintain fluid balance UNIVERSAL SOLVENT Solutes (for example: glucose, proteins, minerals) dissolve in water. TRANSPORT MEDIUM Only 45% of your blood is blood cells, the rest is water Transports nutrients, oxygen, waste materials, hormones Water helps maintain body temp – sweat, or contain heatThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute. Water participates in chemical reactions Water is a lubricant for joints & eyes; mucus & saliva Water is a protective cushion for brain, organ & fetus Water is not stored Water Balance: Water Consumed=Water Lost Dehydration Water loss > water intake Reduced ability to deliver oxygen and nutrients to cells Overhydration: Water intake > water loss Water intoxication increased risk if diarrhea Symptoms of dehydration include: Headache, fatigue Reduced physical and cognitive performance Nausea, confusion, disorientation Can be fatal in extreme conditions Those at risk for dehydration: Elderly, infants (kidneys immature), athletes Excessive diarrhea, vomiting High-protein, high fiber, alcohol  10% - 20% Water Loss è Death Water Intoxication - consume too much water à Hyponatremia , i.e., Sodium in blood too low (diluted), e.g., endurance athletic events, strenuous military training  Needs vary depending on:Level of activityTemperature and humidityDiet  Fluids to replace losses: Water Other fluids: milk, juice, sodaAdequate Intake (AI):  Men= 3.7 liters Women = 2.7 liters/day Caffeine-containing beverages, in moderation Minerals: Essential, inorganic nutrients needed by the body in small amounts for health and maintenance. Minerals required in the diet in amounts greater than 100 mg per day are Major minerals (not more important just req. more) ex Ca Minerals are required in the diet in amounts less than 100 mg: Trace minerals (microminerals) Minerals acquired through the diet from: Unprocessed foods, some processed foods Enriched/fortified foods Dietary supplements May have varying bioavailability.  Examples: The component in whole grains that limit calcium, zinc and iron absorption are known as phytates True or false: spinach is an excellent source of calcium? FALSE Minerals for Fluid Balance=Electrolytes Sodium  + charge: lost a negative electron Extracellular: outside of cells Potassium + charge: lost a negative electron Intracellular: inside of cells Chloride  – charge: gained a negative electron Extracellular: outside of cellsNa, K, & Cl principal electrolytes 1) Maintain fluid balance , 2) Responsible for distribution of water in/between intracellular & extracellular compartments.**Na & K moving across membranes è ‘firing’ of nerve impulses and muscles contracting .**Stimulation increases permeability of the nerve cell membrane to sodium and then to potassium.-Kidneys: increasing or decreasing Na excretion to maintain blood Na.-This mechanism also helps regulate blood pressure. -Small amounts Na lost in stool & sweat. Sodium (Na): RDA 1500 mg/day ; UL 2300 mg/day,  but typical American eats 2400-4800 mg/day Potassium (K):  RDA 4700 mg/day but typical American eats only 2000-3000 mg/day You can lower the amount of sodium by: Cutting down on the amount of salt added in cooking and at the table. Limiting your intake of processed foods****** Use food labels to identify low-sodium/high potassium foods: “low”, “reduced” or “sodium free” If not enough Na in bld, water will move to cells and get swollen cells.  If too much sodium à system is blocked, can’t regulate Na/K and problems with hypertension.Americans consume 2500-5000 mg of sodium!! Processed food is major cause of hypertension - greatest source of sodium. Read the labels! • Sodium Free: 5mg or less/serving• Low Sodium: 140 mg or less/serving• Reduce sodium: contains at lest 25% or less sodium per serving than the reference food itemHypertension: BP consistently at or above 140/90 mm mercury• 1/3 Of Americans have hypertension• Caused by: increased contractions of the heart, increased blood volume or narrowing of the blood vessels• Results in: atherosclerosis, heart attacks, strokes, kidney failure, early death• Treated with: diet, exercise, and medication• Risks: race, age, obesity, diet low in K high in Na, activity Normal BP  Less than 120/80 mm Hg Pre-Hypertension:  Systolic 121-139 or Diastolic 81-89 Hypertension:  140/90 or greater Too much: Generally from overconsumption of: Potassium supplements or salt substitutes Especially in those with impaired kidney functionDASH diet: High in whole grains, fruits, vegetables, and low fat dairy products ~8-10 servings of fruit and vegetables per day 2-3 servings of low fat dairy 6-8 servings of whole