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Water and Minerals. Water. ~60% of adult body weight is water % is higher in kids More muscle, more water Changes in water level can quickly and dramatically impact weight. Water. Functions: Carries nutrients and wastes through body Blood and lymph systems
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Water • ~60% of adult body weight is water • % is higher in kids • More muscle, more water • Changes in water level can quickly and dramatically impact weight
Water • Functions: • Carries nutrients and wastes through body • Blood and lymph systems • Lubricant and cushion around joints, eyes, spinal cord, fetus… • Component of secretions • Mucus, digestive secretions
Water • Functions cont’d: • Aids in regulation of body temp. • Needed for many metabolic reactions • Digestion of proteins, fats and starches • All hydrolysis reactions require the input of water
Water • Maintaining water balance • Goal is to balance water output and input • Water Loss: • Urine • Feces • Sweat (kids and elderly sweat less) • Exhale moist air
Water • Water Input • Water • Other fluids • Water in foods • Water made in metabolism
Water Sources • Good sources of water • Water • Juice* • Sports drinks* • Soups • Fruits and vegetables • * issues with these sources?
Water Sources • Poor Sources – many are diuretics • Caffeine containing coffee, tea, sodas • Alcohol
Water Intake Adults? • Recommend ~ 8-11 cups/day - • Pay attention to thirst – many recommend letting thirst be your guide. • Urine color is also a good indicator
Water Intake • Amount needed depends upon: • Calories eaten, more calories, more water • Muscle mass • Level of exercise • Impacts ______ and _______ • Climate
Blood Volume • Blood volume is regulated by the brain and kidneys • When blood volume is low: • Ion concentrations rise • FYI - Ion concentration may rise without low blood volume, same response occurs • Examples ?
Decreased Blood Volume Consequences low blood volume: • Urine production is reduced • Dark yellow urine • Blood vessels narrow to raise blood pressure • Hypothalamus triggers thirst response • Thirst response ALWAYS lags behind the need for water • Thirst response diminished in elderly
Dehydration • When a water deficiency develops slowly thirst usually takes care of it • When water deficiency occurs quickly dehydration occurs VERY SERIOUS
Dehydration • Symptoms of mild dehydration: • Thirsty • Tired and weak • Impaired performance • Impatient and irritable • Flushed skin • Decreased urine output • Dry mouth
Dehydration • Severe Dehydration – SERIOUS • Skin pale and dry • Headache, can’t concentrate • Shallow rapid breathing • Increased heart rate • Stop sweating • Overheat ….VERY SERIOUS
Dehydration and Over-Heating • Over-heating – athletes and babies die from this every year (others too) • Symptoms, in addition to dehydration: • Shock • Seizures • Coma • Death
Hyponatremia • “Water intoxication” • Fairly rare • Most often occurs with rapid water consumption combined with heavy sweating • Results in a potentially deadly drop in blood levels of sodium.
Electrolytes • Electrolytes are dissolved ions in body fluids • Ion = charged particle • Ions attract water
Electrolytes • Major extracellular ions: • Sodium Na+ Na+ • Chloride Cl - • Major intracellular ion: • Potassium K + Cl - K+
Sodium – Na+ • Major ion outside of cells • Functions: • Primary regulator of extracellular fluid volume • Helps maintain acid-base balance • Essential for nerve and muscle contraction
Sodium – Na+ • Absorption • Absorbed in SI into capillaries • Recommended intake • Minimum 500 mg/day • Maximum 2400 mg/day • A little more than 1 teaspoon
Sodium – Na+ • Food sources • Primary sources of sodium are processed foods, not the salt shaker • Examples of high sodium foods:
Sodium – Na+ • Control of high blood Na+ levels: • Goal is to readjust the sodium to water levels to normal • Thirst mechanism triggered • Drink more water • Kidneys filter the Na+ out and excrete it in the urine (if enough water)
Sodium – Na+ • Low blood Na+ levels: • First ion (with Cl-) to be lost with sweating, bleeding, vomiting, diarrhea…. • In response to low Na + levels, kidneys keep Na+ and excrete more K+ • When Na+ levels drop in these ways you need to replace both the ions and the water
Sodium – Na+ • Can raise levels of Na+ and water by: • Ingesting sports drinks • Drinking dilute juices (add a little salt) • Combining salt containing foods with fluids • Salt pills are never recommended • Pure water may not be the answer either….
Oral Rehydration Solution • 2 tablespoons of Sugar. • 1/2 teaspoon of Salt. • One liter of clean drinking
Sodium – Na+ • Sodium and Hypertension • High sodium intake is associated w/ hypertension in many people (salt sensitive) • Populations at risk • African descent • Family or personal history of hypertension • Over 50 • Diabetic or obese • Chronic kidney disease
Sodium – Na+ • Lowering blood pressure • Reduce sodium intake and increase potassium intake • Reduce intake of processed foods, increase intake of fresh foods • DASH Diet • Lose weight
Sodium – Na+ • High Na+ intake is associated with increased calcium excretion • May contribute to osteoporosis
Potassium - K+ • Major electrolyte inside cells • Functions: • Plays a major role in maintaining fluid and electrolyte balance • Needed for nerve and muscle contraction • Required for a steady heart beat • Plays a role in carb and protein metabolism
Potassium - K+ • Absorption – occurs in SI blood • Recommended intake • Minimum 4700 mg/day
Potassium - K+ • Food sources • Fresh foods (intact cells) • Fresh fruits and vegetables • See page 412 • Processing lowers K+ levels and raises Na+ levels • See page 409
Potassium - K+ • Potassium and Health • Low K+ intake is associated with increased blood pressure • High K+ intake may reduce or help prevent hypertension • High K+ intake may lower risk of stroke
Potassium - K+ • Potassium deficiency • Most common electrolyte imbalance • Occurs most often due to excessive losses not a low intake • Symptoms • Muscular weakness (first symptom) • Confusion • Paralysis • Heart failure may occur
Potassium - K+ • Potassium Toxicity • Body excretes excess in urine • Any toxicity will come from supplements, not foods • Muscle weakness and vomiting • A shot of potassium into a vein can cause the heart to STOP = death
Calcium – Ca+2 • Ca is the most abundant mineral in the body • 99% in bones and teeth as hydroxyapatite • On a collagen matrix • 1% in blood as Ca+2 • Blood level of calcium is tightly controlled
Calcium • Absorption • Occurs in the SI • To be absorbed the Ca must bind to a Ca binding protein • Vit D activates the binding protein
Calcium • % Absorption • Adults: ~30% • Kids: ~ 50-60% • Pregnancy: ~50%
Calcium – Ca+2 • Functions • Bones • Key component (along with P) of bone structure • Serve as a calcium bank for the blood
Calcium – Ca+2 • Functions - In Blood • Regulates muscle contraction • Needed for nerve function • Plays a role in blood clotting
Calcium – Ca+2 • Functions – In Blood • Plays a role in hormone secretion • Activates some enzyme reactions • Activates protein (calmodulin) that helps regulate blood pressure
Calcium Balance • Calcium Balance • Calcium is constantly moving in and out of bones • Intake must be adequate to replace all Ca taken out of bones
Calcium Balance • When blood calcium levels go up: • Hormones and vit D promote deposition of Ca into bones • Key hormone for lowering blood Ca is calcitonin
Calcium Balance • Calcitonin – lowers blood Ca • Inhibits vit D activation • Less Ca absorbed • Prevents Ca reabsorption in kidneys • More Ca excreted in the urine • Slows breakdown of bones
Calcium Balance • When blood calcium levels are low: • Key hormone in raising Ca levels is parathormone • Calcium absorption goes up in SI • assuming Ca in diet and vit D present • Bones release more Ca into blood • Kidneys excrete less Ca
Calcium Requirements • Calcium Adequate Intake • Adults 19-50: 1000 mg/day • Adults 51+: 1200 mg/day • Pregnant or lactating: 1000 mg/day • Kids/teens: 1300 mg/day
Calcium Sources • Food Sources • Dairy products – great sources of Ca, many also contain vitamin D • 1 cup milk = 300 mg Ca • 1 cup yogurt = 450 mg Ca • 1 ounce hard cheese = 200 mg • ½ cup ice cream = 100 mg • Drawback - many are high in fat and cholesterol
Calcium Sources • Food Sources • Dark green leafy vegetables • Fairly good = mustard greens, kale, broccoli • Not as good = spinach and Swiss chard • Contain oxalates and phytates which lower the bioavailability of the Ca • 8 cups of spinach = 1 glass milk
Calcium Sources • Food Sources • Nuts and legumes (limited calcium) • Calcium fortified products • Orange juice • Soy and rice milk • Cereals…..