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Agenda. A cool website: http://easybib.com / Lecture Water Functions Needs Minerals Major Trace. Lecture 12: Water and Minerals. 2/16/2012 Will Brown. Water. Water. Water acts as a solvent for most of the nutrients we consume
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Agenda • A cool website: http://easybib.com/ • Lecture • Water • Functions • Needs • Minerals • Major • Trace
Lecture 12: Water and Minerals 2/16/2012 Will Brown
Water • Water acts as a solvent for most of the nutrients we consume • Needs constant replenishment – due to respiration, excretion, urination, digestion, etc. • Need to take in ~13 cups of water for men and 9 cups for women • About 50-70% of body weight is water • The thinner you are the higher % of water you are • Lean muscle = 73% water • Fat = ~20% water
Water • Water is thought to move freely once inside the body • When inside the cells called intracellular fluid • Outside or in the blood is called extracellular fluid • Electrolyte movement is controlled across cell membranes • Water is controlled by osmosis • Intracellular fluid regulated by potassium and phosphate • Extracellular regulated by sodium and chloride • Certain instances when this is not the case • Blood/Brain barrier • Blood/Testis barrier • Intestinal barrier
Functions of Water • Acts as a solvent • Regulate body temp • Water has a high specific heat = 5861.8 joules/kg • Much lower than fat; oleic acid = 2884 joules/kg • This helps keep the body from freezing quickly • Perspiration helps to cool the body via evaporation • Remove waste – Urine is water soluble • Important in mucous production • Amniotic fluid is primarily water
Significant Water Loss • If to little water is ingested, the body will increase water retention • Antidiuretic hormone – released from the pituitary gland and causes kidneys to preserve more water than normal • Aldosterone – causes retention of sodium • 1-2% fluid loss the body will feel thirst • At 4% muscles begin to lose strength • At 10-12% heat tolerance is decreased and weakness • At 20% death is soon to come
Daily Water Intake and Output Input Output Skin perspiration 750 ml or 3 cups Lung Respiration 300 ml or 1.25 cups Urine 1650 ml or 6.75 cups Feces 100 ml or 0.4 cups Total water output 2800 ml or 10 cups • Fluids • 2000 ml or 8 cups • Water content in foods • 500 ml or 2 cups • Water produced from metabolism • 300 ml or 1.25 cups • Total water intake • 2800 ml or 10 cups
Minerals: an Overview • Minerals are broken into two categories • Major – >100 mg/day • Calcium, Phosphorus, Potassium, • Trace – <100 mg/day • Iron, Manganese, Copper, Iodine • Functions cover a broad spectrum • Cofactors - Selenium • Add strength to body structures – Calcium • Signal transduction – Potassium and Sodium
Minerals: An Overview • Bioavailability – How much of a substances makes it into the body compared to what we eat. • It is different for each mineral and which food you eat for that mineral • Spinach is high in Calcium but also high in oxalic acid which binds Ca+ which the body can’t absorb • Only ~5% can be absorbed • Minerals come from both plant and animal sources • Animal sources are better absorbed because things like fiber aren’t present to hinder absorption • Mineral content in plants varies greatly depending on the concentration of the minerals in the soil • Can affect vegetarian and vegan diets
Minerals: an Overview • The more refined a food, the less minerals will be present • Most minerals are ions and water soluble • In flour, there is a broad array of minerals present but iron is only one added back • Fiber impedes mineral absorption, not just carbs • Certain fibers can bind to minerals • Increased fiber can mean decreased mineral availability • Yeast leavened bread can increase bioavailability • Zinc and phytic acid
Minerals: an Overview • Mineral-mineral interactions occur • Same size, same charge compete for absorption • Excess of one mineral reduces the bioavailability of the others • Another reason to not take a Multi-Vitamin you are not getting everything written on the bottle • Only take mineral supplements when medically necessary – ie: anemia • Vitamin-mineral interactions • Most of these are beneficial • Vitamin D increases Calcium absorption • Vitamin C keeps iron in the most available form • Mineral Toxicity • Trace minerals have a very narrow therapeutic window • Supplements typically exceed RDA • Contamination with things like lead can occur • Only take mineral supplements approved by the United States Pharmacopeia
Major Minerals: Sodium • Salt! Most of the sodium comes from table salt and processed food • Most bioavailable of all minerals almost 100% • Functions • Primary ion in extracellular fluid – required for water balance • Helps with nerve signals • Helps kidneys reabsorb water • Low sodium, is rare, but usually caused by sickness and low dietary sodium • Nausea, vomiting, muscle cramps, dizziness
Major Minerals: Sodium • Major sources are processed breads, deli meats and fast food meals. • Adequate Intake – under 51 (yoa) is 1500 mg • If we ate no processed foods the intake would be ~500 mg • Upper limit is 2300 mg – about 1 tsp • Hypertension is 1500 mg • Only need 200 mg/day to maintain regular function • People of African descent are more sensitive to sodium - <1500 mg/day • Excess urine is excreted in the urine • Hypertension is biggest concern for excess sodium intake
Major Minerals: Potassium • Similar in function to Sodium; however acts intracellular • 95% of K in the body is intracellular • Absorb ~90% • Associated with lower blood pressure • Low potassium leads to loss of appetite, cramps, confusion, constipation • Eventually, heart arrhythmias develop leading to death • Sources: unprocessed foods such as fruits, vegetables, whole grains, • COFFEE!!! Starbucks is only trying to make sure you get your daily potassium intake. Thanks Starbucks.
Major Minerals: Potassium • Adequate Intake: 4700 mg/day • 3500 mg is value used on food labels • Most Americans consume 2000-3000 mg/day • No upper limit to potassium – kidneys are able to regulate potassium quite well • People at risk for low potassium • Some high blood pressure meds that are diuretics deplete potassium • Excessive vomiting and diarrhea can lead to low potassium • primary issue with cholera • Low calorie diets • Atheletes – because of sweating
Major Minerals: Chloride • The other half of SALT!!! • Functions • Balances out positive ions such as sodium • Part of the stomach acid production • Nerve function • Sources • Chlorinated water • Some fruits and veggies • Table salt • Adequate intake is 2300 mg/day – average intake is 5400 mg/day • Upper limit is 3600 mg/day
Major minerals: Calcium • Bioavailability of Calcium is ~25% for adults • As high as 60% for infants and children • Lower for elderly • More affected by absorption than Na+ of K+ • Most occurs in duodenum, more acidic than other areas of the lower GI • Calcium enhanced by • Parathyroid hormone • Gradual flow of digestive contents • Glucose and lactose • Impeded by • Large amount of phytic acid in fiber from grains • Great excess of phosphorus in the diet • Polyphenols in tea • Vitamin D deficiency • Diarrhea • Old age
Major Minerals: Calcium • Functions • Bone structure – 99% of calcium in the body is stored in bone • Clotting • Muscle function • Nerve function • Helps regulate cellular metabolism • Sources • Milk – provides 75% of the calcium of North Americans • Leafy greens • Broccoli • Sardines and Salmon
Major Minerals: Calcium • Adequate intake: 1000-1200 mg/day • Average intakes in US are 800 for females and 1000 for males • Most women, especially young women and vegans, are below adequate intake • Upper limit is 2500 mg/day based on increased risk of kidney stones • Supplements • Many types of calcium supplements available • Should be taken after/with a meal, acidity helps with absorption • Some supplements contain lead and are not regulated by FDA
Major Minerals: Phosphorus • Bioavailability of 70% • Found in many types of food and widely available • Vitamin D also affects Phosphorus uptake • Functions • Component of enzymes • Forms backbone of DNA • Cell membrane phospholipids • Bone
Major Minerals: Phosphorus • Adequate intake: 800 mg/day; 1000mg used on food labels • Most people easily meet this because it is so readily available • Upper intake is 3-4 g/day; based in kidney impairment • Interesting condition can arise when low calcium and high phosphorus is found in the body • Causes bone loss • Occurs in elderly • Also occurs in teens due to high soft drink consumption • Phosphorus is as a flavoring agent; 75mg/12oz
Major Mineral: Magnesium • Bioavailability is 40-60%; can go as high as 80% when intakes are low • Functions • Used in hundreds of enzymes • Important for nerve function • Deficiency leads to arrhythmia, weakness, disorientation, muscle pain • Rare because body can store excess Mg • Adequate Mg reduces CV risk
Major Mineral: Magnesium • Adequate intake is 400 mg for men and 310 mg for women • Most people fall under this, recommended to increase whole grain and green veggies • Upper limit for non-food sources only is 350 mg/day • Sources include whole grains, broccoli, potatoes, squash. • Some can come from meats but not as much as plant sources • Also hard tap water and coffee
Trace Minerals: Iron • Bioavailability is ~18%; higher in anemics • Used in every cell in the body as oxygen carrier • Two main forms • Hemoglobin – carries oxygen to cells from lung • Myoglobin – intramuscular carrier of oxygen • Two main types of Iron that are ingested • Heme iron – the kind found in animals • More easily absorbed • Nonheme iron – elemental form and not as easily absorbed • Absorption can be enhanced by orange juice • Absorption impeded by phytic acid in fiber
Trace Minerals: Iron • Absorption of iron tightly regulated • Absorbed by absorptive cells and held • If low iron in blood then it will be taken up into blood stream • If not taken up, shed with intestinal cells at the end of their 2-5 day life cycle • Functions • Carry oxygen • Used in enzymes and proteins
Trace Minerals: Iron • Adequate intake for men and women over 50 is 8 mg/day; 18 mg/day for women 19-50 • Upper limit is 45 mg/day due to stomach irritation • Large doses over 60 mg can be life-threatening to small children • Easiest source is animal meat (heme iron) and spinach, peas and legumes (nonheme iron)
Trace Minerals: Zinc • Bioavailability is ~40% • Significantly impacted by the types of foods eaten • Animal sources more readily absorbed • Grains are low in zinc; high in phytic acid rich fiber can significantly reduce absorption • Other minerals compete for absorption • Zn deficiency in children causes growth retardation and poor sexual development • Can be a big problem for cultures that rely heavily on cereal grains for primary protein source
Trace Minerals: Zinc • Functions – involved in hundreds of enzymes and gene regulatory proteins • DNA synthesis and function • Protein expression • Protein metabolism • See page 379 in book for more • Sources • Animal protein usually supplies half of Zn requirements • Plant sources include whole grains, peanuts, and legumes • Adequate intake is 11 mg/day for men 8 for women • Upper limit is 40 mg/day due to interferences with Cu
Trace Minerals: Selenium • Exists in many readily absorbable forms • Functions as part of antioxidants and thyroid hormone metabolism • Deficiency leads muscle pain and wasting; also heart disorders • Sources: fish, organ meat (woo!) eggs, and grains grown in selenium containing soil • Adequate intake is 55ug/day • Upper limit is 400ug/day based on things like hair loss
Trace Minerals: Iodide • Iodine required for the production of thyroxine, a thyroid hormone necessary for metabolism homeostasis • Found in food as Iodide • Deficiency leads to goiter and cretinism • Goiter is an enlarged thyroid; small goiters not a problem but large ones can put pressure on wind pipe • Cretinism is caused when pregnant mothers do not have enough iodide; leads to stunted growth and mental retardation • Easily prevented with iodide supplementation • Still prevalent in many iodide deficient areas of the world that have not adopted fortification
Trace Minerals: Iodide • Adequate intake: 150 ug/day • Amounts to ½ tsp of fortified salt • Most people consume that amount • Upper limit 1.1 mg/day and can impair thyroid function • Sources include saltwater fish, iodized salt, dairy products, and small amount in grains • Used as a sterilizing agent in dairy processing and in fast food restaurants • Used as bread conditioner in bakeries • Can be a food colorant • Found in iodized salt – not sea salt, the iodide is lost during processing • Vegans may need to supplement with iodized salt
Trace Minerals: Copper • Bioavailability is 12-75% with an inverse absorption pattern similar to Vitamin C • Absorbed primarily in stomach and SI • Functions: • Involved in synthesis of hemoglobin • Involved in certain enzyme function • Important in immune cell function, blood clotting, and lipoprotein metabolism • Deficiency leads to a rare form of anemia, low WBC count, bone loss, poor growth and types of cardiovascular disease
Trace minerals: Copper • Adequate intake: 900 ug/day • The amount on food labels is 2 mg/day • Average intake is 1-1.6 mg/day • Supplement form is copper oxide is poorly absorbed • Upper limit is 10 mg/day – causes vomiting and liver toxicity • Sources include liver, seafood, cocoa, legumes, nuts, seeds, and whole grain breads and cerel • Copper deficiency found primarily in preterm infants, patients recovering from intestinal surgery, and those on high zinc supplementation
Trace minerals: Fluoride • Not to be confused with Fluorine (F2) which is a poisonous gas • Functions • Aids in the formation of a tooth enamel that resists bacteria acid • Results in 40-60% less cavities in kids that drink fluoridated water • Prevents bacterial growth in the mouth • Fluoride present in saliva helps to prevent demineralization and increases remineralization
Trace Minerals: • Adequate intake: 3.1 to 3.8 mg/day for adults • Most municipal water systems add fluoride to 1 mg/L • Upper limit for children is 1.3 to 2.2 mg/day and 10 mg/day for adults and kids >9 • This is to prevent tooth mottling • Worth noting: most bottled waters do not have fluoride • May need to supplement children if primary water source is bottled
Trace Minerals: Chromium • Fairly early in our understanding of Chromium • Enhances in glucose uptake into cells • Deficiency leads to impaired blood glucose control, elevated blood cholesterol and triglycerides • Adequate intake is 25-35 mg/day • No upper limit found in food sources • Sources include egg yolks, organ meat, mushrooms, and BEER!?!
Trace Minerals: Manganese • Functions • Used by enzymes in carbohydrate metabolism • Used by superoxide dismutase which metabolizes free radicals • No deficiency found • Sources include nuts, rice, oats and whole grains • Adequate intake is 1.8-2.3 mg/day • Upper limit is 11 mg/day and based on nerve damage
Trace Minerals: Molybdenum • Used in many enzymes • Deficiency only found in people with are maintained on IV nutrition • Symptoms include increased heart and respiration, night blindness, mental confusion, edema, and weakness • Sources include dairy products, beans, whole grains, and nuts • Adequate intake is 45 ug • Food labels use 75 ug which is average daily intake • Upper limit is 2 mg/day based on animal tests