Unit 5 Fluid and Electrolyte Balance and Antioxidant Function

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1 Nutrients Involved in Fluid and Electrolyte Balance What Constitutes Body Fluids? Is it just? Unit 5 Fluid and Electrolyte Balance and Antioxidant Function Composed of that move past one another freely Characterized by its ability to conform to the shape of the container that holds it About % of healthy adult body weight Why such a large range? The body fluid composition of tissue varies by Body Fluids : lean tissues have higher fluid content than fat tissues : males have more lean tissue and therefore more body fluid : lean tissue is lost with age and body fluid is lost with it Fluid the cell of body fluid Fluid the cell of body fluid fluid flows between cells that make up a particular tissue or organ fluid is the water in the blood and lymph Plasma? blood cells within arteries, veins, and capillaries What are Electrolytes? Substance that dissolves in solution into electrically charged particles Positive charge:, potassium Negative charge: chloride, Predominant electrolytes Extracellular fluid:, chloride Intracellular fluid:, phosphorus What are the Functions of Body Fluids? Fluids and substances Water is an excellent because it dissolves a variety of substances Blood plasma transport in the body

2 Water soluble substances: amino acids, glucose, vitamins, minerals, medications Fat soluble substances must be attached to or surrounded by water soluble proteins Fluids account for blood Appropriate fluid levels is essential for maintaining healthful blood volume Blood pressure when blood volume rises High blood pressure ( ) is a risk factor for heart disease and stroke Low blood pressure can cause people to feel tired, confused, or dizzy Kidneys help to regulate blood volume and blood pressure But how? Antidiuretic hormone ( ) stimulates the kidneys to reabsorb water, reducing urine responds to decreased blood pressure Angiotensin II raise blood pressure signals the kidneys to retain sodium and chloride, thereby retaining water Fluids help maintain body Body temperature must be within a safe range High heat capacity of water means that the temperature of our body fluids remains stable Sweating releases heat as the evaporation of water from the skin the skin and blood Protect and Lubricate Cerebrospinal fluid protects the brain & spinal cord fluid protects the fetus Synovial fluid lubricates Digestive juice (saliva) moistens food for ease of swallowing and transport What are the Functions of Electrolytes? Electrolytes help regulate fluid Cell membranes are to water, but freely permeable to electrolytes Water follows the movement of electrolytes, moving by to areas where the concentration of electrolytes is high. This action provides a means to control movement of water into and out of the cells Fluid and Electrolyte Balance pressure keeps electrolytes in solution from drawing liquid toward them across a semi-permeable membrane Electrolytes enable nerves to respond to Nerve are initiated at nerve cell membranes in response to a change in electrical charge across the membrane Depolarization Action Potential Repolarization Sodium and potassium ensure that nerve impulses are generated, transmitted, and completed Electrolytes signal muscles to Muscles are stimulated to contract in response to stimulation of nerve cells Influx of into the muscle from the extracellular space stimulates contraction

3 Muscles can relax after contraction once the electrical signal is complete and calcium is pumped out of the muscle cell How are Fluids Balanced in the Body? Thirst mechanism ( ) prompts us to drink when it is stimulated by Increased of salt and other dissolved substances in the blood A reduction in blood and blood, such as during profuse sweating, vomiting, diarrhea, low fluid intake in mouth and throat with low saliva signals the kidneys to retain water How are Fluids Gained? Most water enters the body through Some have very high water contents Metabolic water is a product of chemical reactions in the body ( % body s needs) How are Fluids Lost? Most water is lost through Kidneys control how much water is Excess water is processed by the kidneys and excreted as. Insensible water is lost through the skin ( ) or through the lungs during exhalation Significant loss: exercise, illnesses, injury, surgery, high altitude, diuretics Water Intake Guidelines Water Essential for life Required for fluid and balance and many reactions Recommended intake DRI: 2.7 liters for the adult female, 3.7 liters for the adult male Varies with age, body size, health status, physical activity level, environment What if you drink too much water? Becoming over hydrated is Can result in a of sodium What if you don t drink enough water? Infants and the elderly are especially vulnerable Minerals important in Fluid Balance ( ) Food sources? Functions Major positively charged electrolyte in the fluid Associated with blood and ph balance in the body Required for nerve impulse transmission

4 Muscle and Assists in glucose absorption from the small intestine AI: 1500 mg, most recommend <2300 mg/day Deficiency symptoms is an abnormally low blood sodium level Can result from prolonged vomiting, diarrhea, or sweating Has been seen in athletes who consume too much water Toxicity is abnormally high blood sodium concentration Can happen to patients with congestive heart failure or kidney disease These patients don t have the ability to excrete Na effectively Results in high blood volume,, and high blood pressure Potassium ( ) Food Sources Processing foods sodium and potassium content Good sources: fresh fruits, vegetables, and whole grains Most salt substitutes are made from potassium chloride Functions Major positively charged electrolyte in the fluid Together with sodium, maintains fluid balance and regulates the contraction of muscles and transmission of nerve impulses High potassium intake helps to maintain a blood pressure 4700 mg/day Deficiency is low blood potassium levels Can be seen in patients with kidney disease or diabetic Can occur when taking certain diuretics and with extreme dehydration, vomiting, diarrhea, alcohol abuse, long-term consumption of natural licorice (glycyrrhizic acid or GZA), or eating disorder (abnormal heart rhythms) Toxicity is a high blood potassium level People with kidney disease are unable to regulate their blood potassium levels and should avoid consuming potassium-containing salt substitutes Can alter normal heart rhythm resulting in a heart attack and Must avoid consuming potassium-containing salt substitutes (Cl) Food Sources? Functions Coupled with sodium in the fluid to maintain fluid balance

5 Part of hydrochloric acid ( ) in stomach aiding digestion Assists in the transmission of nerve impulses AI: 2300 mg/day Deficiency This is but can occur in people with severe dehydration, frequent vomiting, and eating disorders Toxicity All dietary chloride come from May lead to hypertension in salt-sensitive patients (P) Food Sources Found in many foods Found in high amounts in foods that contain (such as meat, milk, eggs) More readily absorbed from animal sources RDA for phosphorus is 700 mg/day Function The major negatively charged Required for balance Critical role in formation Regulates biochemical reactions by activating or deactivating enzymes (phosphorylation) Found in ATP, DNA, RNA, cell membranes (phospholipids), and lipoproteins Toxicity High blood phosphorus can occur with kidney disease or when taking too many vitamin supplements Causes muscle spasms, convulsions Deficiencies Contribute to loss Decrease growth Poor tooth development Medical Disorders Related to Fluid and Electrolyte Imbalances Dehydration Dehydration occurs when water loss water intake Commonly due to heavy or high environmental temperatures Infants and the elderly are more at risk What is the best way to see if you are dehydrated? Water Intoxication Rare Kidney disease or under consumption of electrolytes

6 Heat Stroke Heat stroke occurs if the body s temperature regulation mechanisms Occurs in hot, humid environments Symptoms include rapid pulse, hot, dry skin, high body temp, loss of consciousness Has been fatal for athletes during exercise in extreme heat Stop exercising when feeling dizzy, light-headed, disoriented, or nauseated Hypertension Hypertension is a major condition characterized by blood pressure. Systolic pressure over mm Hg Diastolic pressure over mm Hg May not show symptoms - Increases a person s risk of heart disease, stroke, kidney disease Can reduce brain function, impair physical mobility, and cause death What causes hypertension? Primary (or essential) hypertension: unknown cause for % of cases 5 10% are caused by kidney disease, sleep apnea, and chronic alcohol abuse sensitivity: >50% adults with hypertension Recommendations for reducing hypertension: Losing Increasing activity Reducing intake Reducing intake Eating more whole grains, fruits, vegetables, and low-fat dairy foods DASH diet Medications Help in normalizing blood pressure Should also continue to practice healthful changes Hypertension: "the silent killer" Often no obvious of this disease Importance of regular blood pressure check Neuropsychiatric and Muscle Disorders Electrolyte imbalances can result in or Electrolyte imbalances cause changes in nervous system function and impair cognition Nervous system changes can alter proper muscle function Kidney and Heart-Related Disorders Kidney Disorders Kidneys have role in regulation of fluid, electrolyte, and acid-base balance Kidney disease can lead to and fluid retention Congestive Heart Failure Heart can no longer pump adequate supply of blood throughout the Heart can fail on the left or right sides, with varying consequences

7 Obesity Popularity of sweetened (U.S.) 21% of calories from beverages: sweetened soft drinks, fruit juices, sweetened bottled waters, bottled teas, specialty coffee Appetite curbed: extra calories from drinks are not compensated for by eating less Displace more nutritious beverages such as milk (source of protein, calcium, vitamin D, and other nutrients important for bone health) Nutrients Involved in Antioxidant Function What are Antioxidants? Compounds that protect cells from the damage caused by What is Oxidation? Structure of Atoms Remember the structure of the atom and how they come together to form molecules During metabolic reactions, electrons can be transferred and molecules Oxidation-Reduction reactions Exchange Reactions is a chemical reaction in which atoms lose electrons occurs when atoms gain a electron Free Radicals Stable atoms have an even number of electrons ( ) orbiting Electron loss during oxidation leaves an odd number or electron Unstable atoms are called Reactive oxygen species (ROS): molecule that becomes a free radical What Causes Free Radicals to Form? Many processes Digestion and absorption of Immune system fighting infections Environmental factors Excess sunlight Toxic substances Tobacco Asbestos Cell Damage Free radicals form within the of cell membranes Damaged lipid molecules are unable to maintain the integrity of the cell membrane Diseases Linked with Free Radicals Various cancers Heart disease Diabetes

8 How do Antioxidants Work? Antioxidants free radicals and repair the damage they cause Antioxidant donate their electrons or hydrogen molecules to free radicals to stabilize them and reduce oxidation damage Antioxidant function within the enzyme systems that convert free radicals to less damaging substances that can be excreted help stabilize free radicals Antioxidant Enzymes Antioxidant enzymes/enzyme systems: Break down fatty acids Make more vitamin antioxidants available to fight other free radicals Antioxidant enzymes: converts free radicals to less damaging substances, such as hydrogen peroxide removes hydrogen peroxide from the body removes hydrogen peroxide Profile of Nutrients that Function as Antioxidants Vitamin E soluble Incorporated into the to be transported to the liver Incorporated into very low-density lipoproteins ( ) Stored in adipose tissue ( %) and cell membranes Forms of Vitamin E compounds are the biologically active forms is most active (potent), found in food and supplements RDA: expressed as alpha-tocopherol (mg/day) Food labels and supplements: expressed as alpha-tocopherol equivalents or International Units (IU) Food Sources Vitamin E is wide spread in foods Vegetable oils (Safflower, sunflower, canola, soybean) Nuts, seeds, wheat germ, soybeans RDA is 15 mg alpha tocopherol per day Functions Protects Lipids from Free Radicals: Polyunsaturated fatty acids ( ) Cell from oxidization Normal nerve and muscle development Enhances immune system

9 Added to oil-based foods and skincare products to rancidity and spoilage Promotes vitamin A absorption, if low Deficiency True deficiency is uncommon Can result in Rupturing of red blood cells causing anemia Premature infants most susceptible Symptoms: loss of muscle coordination and reflexes; impaired vision, speech, and movement Impair immune functions (with low selenium) Associated with fat Toxicity Tolerable Upper Intake Level (UL): 1,000 mg alpha-tocopherol per day High supplemental doses of vitamin E may be harmful for certain individuals Side effects: nausea, intestinal distress, and diarrhea Interacts with anticoagulants (aspirin, Coumadin) Long-term use may cause hemorrhagic stroke Inhibits the synthesis of Vitamin Vitamin C -soluble Must be consumed on a regular basis Food Sources Fresh fruits and vegetables by heat and oxygen Minimize loss by steaming, microwaving, and stir-frying Functions Synthesizes (prevents scurvy) Neurotransmitters (serotonin) Carnitine (transports long-chain fatty acids) Hormones (thyroxine, epinephrine, steroids) Enhances iron absorption Reduces, cancer-causing agent found in cured and processed meats Antioxidant protects LDL-cholesterol from Lungs from ozone and damage White blood cells (enhances immune function) Regenerates vitamin E by donating electrons RDA is 90 mg/day for men, 75 mg/day for women UL: 2,000 mg/day for adults

10 Smokers require additional mg/day Other situations requiring more vitamin C: from traumatic injury, surgery, burns use of oral contraceptives no consensus as to additional amounts Deficiency Rare, most common deficiency disease Symptoms include bleeding gums, loose teeth, weakness, wounds that fail to heal, depression Anemia can result High risk for deficiency among people who Eat few fruits and vegetables Abuse alcohol and drugs Toxicity Water soluble, extra is Consuming excess is not toxic Only supplements can lead to toxic doses Long-term excess of 2,000 mg/day: nausea, diarrhea, nosebleeds, and abdominal cramps Harmful for people with (excess iron accumulation in the body) Vitamin A soluble Excess is stored in the liver, adipose tissues, kidneys, and lungs Expressed as Retinol Activity Equivalents ( ) International Units ( ) for vitamin A on food labels or dietary supplements Active forms: Retinol,, Retinoic acid Food sources (liver, eggs, whole-fat dairy, fortified foods) (red, orange, yellow, and deep-green fruits and vegetables that are high in beta carotene can be converted to vitamin A) Function Antioxidant, free radicals and protects LDL from oxidation Essential for proper Cell, process by which stem cells mature into specialized cells Sperm production and fertilization Bone growth RDA is 900 micrograms/day for men, 700 micrograms/day for women UL is 3000 micrograms/day of preformed vitamin A Deficiency & xerophthalmia

11 Toxicity Highly toxic at times RDA, mainly from supplements Birth defects ( ) Damage to liver and eyes Symptoms: loss of appetite, blurred vision, hair loss, skin disorders Beta Carotene Beta carotene is a, a classification of phytochemical A, inactive form (precursor) of vitamin A to be converted to active retinol Expressed in food as Retinol Activity Equivalents (RAE) which indicates how much active vitamin A is available in the body after conversion Food sources Red, orange, yellow and deep-green fruits and vegetables Heating improves digestibility and absorption Function Weak Effective against lipid oxidation in cell Enhance system Protect skin from UV light damage Protect eyes from damage, preventing or delaying age-related vision impairment Beta carotene is not an essential nutrient No DRI or RDA established Consuming 6 to 10 mg of beta-carotene per day from food sources may reduce risks for cancer and heart disease Deficiency No known deficiency symptoms Toxicity or is harmless and reversible Skin changing color? Usually adequate amounts in diet; supplementation is not recommended Selenium: Se mineral needed in small amounts Food Sources Functions of Selenium : spares vitamin E enzyme family Protects the heart and other cells from oxidative damage (thyroid hormone) production: basal metabolism, body temperature

12 RDA = 55 μg/d Average intake exceeds RDA Selenium-Deficiency Diseases Causes Low intake due to low content Why so high in animal tissues? Consequences of deficiency Muscle Muscle Kashin-Beck disease, deforming arthritis Impaired immunity Keshan disease Heart disease in children Accumulation of fatty acid in the heart Increase blood clots Irreversible Upper Level for Selenium UL = 400 ug/day Consequences of toxicity breath Hair loss Nausea, vomiting Weakness Rashes Cirrhosis of the liver Additional Antioxidants a compound needed for proper enzyme function These minerals play critical roles in health and metabolism:,, and are part of the superoxide dismutase enzyme antioxidant complex is part of the catalase structure Cancer Cancer: a group of diseases characterized by cells growing " " cancer cells aggressively tissues and organs throughout the body : immature undifferentiated cell masses that have no physiologic function (cancerous) (harmless) Primary steps of cancer development:

13 Cancer Risk Risk factors Tobacco use Overweight, Poor nutrition (diets high in saturated fats; low in fruits & vegetables; excessive alcohol consumption) Physical Infectious agents Ultraviolet radiation Antioxidants play a role in cancer prevention immune system cancer cell growth oxidative damage to cells Eat a varied, healthful diet Be physically active Maintain a healthy body weight Quit or don't start Avoid infectious agents and UV radiation Naturally occurring chemicals in plants May reduce risk for cancer, heart disease Include phytoestrogen, lycopene, and flavonoids Found in whole grains, fruits, vegetables, legumes, nuts, garlic, and soy products Cardiovascular Disease ( ) Leading cause of death among adults in USA Includes all diseases of the heart and blood vessels heart disease (high blood pressure) (hardening of the arteries) Primary manifestations of CVD: Major Risk Factors for CVD Hypertension High blood levels of low density lipoprotein (LDL) cholesterol Obesity Sedentary lifestyle Other Risk Factors for CVD Low blood levels of high density lipoprotein (HDL) cholesterol Impaired glucose tolerance or diabetes

14 Family history of CVD males before age females before age Being male older than years Being postmenopausal in women Low-Grade Inflammation May be even more important than elevated levels Weakens plaque in blood vessels (vessels become more fragile) Plaques likely to burst, break away, lodge in blood vessels of heart or brain and close off blood supply, resulting in a heart attack or stroke C-reactive protein ( ) Marker for inflammation ( ) Associated with high risk for heart attack in the presence of normal cholesterol levels High CRP and high cholesterol can increase the risk for heart attack Antioxidants and CVD Antioxidants (vitamins E and lycopene) reduce damage to blood vessels: free radicals low-grade inflammation blood coagulation and clot formation In fruits, vegetables, and whole grains Dietary fiber (soluble):oatmeal and oat bran Folate (reduce homocysteine-cvd risk factor) Others (flavonoids): tea Aging Process Associated with increased oxidative damage and reduced activity of antioxidant enzymes in most body tissues Digestion, absorption, and metabolism of nutrients are impaired with age Vision Impairment Diseases associated with degeneration Leading cause of Deterioration of center portion of retina Marked by loss or distortion of central vision Damaged portion of eye s lens causing cloudy vision Antioxidants and Vision Impairment Possible role of antioxidants in vision impairment Lack of nutrients (including antioxidants) Free-radical damage caused by exposure to oxygen, UV light, and x-rays Inflammation from eye disease Current research does not support the use of antioxidant supplements in reversing or delaying aging