1323Chapter 8 minerals and water

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Chapter Minerals and Water © 2012 Pearson Education, Inc Why Is Water So Important? Water is the most abundant substance in body  Average healthy adult is about 60 percent water  Muscle: 65 percent water, fat: 10 to 40 percent water  Age and body composition influence the % of water in the body  We can only survive a few days without water Nutrition and You, 2e © 2012 Pearson Education, Inc Your Body is Mostly Water Figure 8.1 Nutrition and You, 2e © 2012 Pearson Education, Inc Body Water Balance  Water is balanced among fluid compartments  Intracellular fluids: inside cells (60-75% of body water)  Extracellular fluids: interstitial fluid between cells and fluid in the blood (25-40% of body water)  Electrolytes: minerals that help maintain fluid balance Nutrition and You, 2e © 2012 Pearson Education, Inc Water as Part of Body Fluids Figure 8.2 Nutrition and You, 2e © 2012 Pearson Education, Inc Functions of Body Water  Acts as universal solvent and a transport medium  Medium for many chemical reactions in body  As part of blood, helps transport oxygen, nutrients, hormones to cells  As part of interstitial fluid (between cells), helps transport waste products away from cells for excretion  Helps maintain body temperature  Is a lubricant for joints, eyes, and is part of mucus and saliva  Is a protective cushion for brain, organs, fetus Nutrition and You, 2e © 2012 Pearson Education, Inc Water Helps Regulate Your Body Temperature Figure 8.3 Nutrition and You, 2e © 2012 Pearson Education, Inc Maintaining Water Balance  Water balance: water consumed = water lost  We take in water through beverages and food  We lose water through the kidneys (as urine), large intestine, lungs, and skin (as sweat)  Insensible water loss: through evaporation from skin and when we exhale Nutrition and You, 2e © 2012 Pearson Education, Inc The Concept of Water Balance: Intake Equals Output Figure 8.4 Nutrition and You, 2e © 2012 Pearson Education, Inc Water Content of Foods Figure 8.7 Nutrition and You, 2e © 2012 Pearson Education, Inc Iron Sources and Physical Needs Food Source Iron Nutrition and You, 2e © 2012 Pearson Education, Inc What if we don’t get enough iron?  Iron deficiency is the most common nutritional deficiency in the world  Risk groups:  Women during the childbearing years  Anyone in a growth stage  Early signs and symptoms include weakness, tiredness, poor attention span, poor appetite, increased susceptibility to infection  Iron deficiency anemia occurs when hemoglobin levels decrease Nutrition and You, 2e © 2012 Pearson Education, Inc Healthy Red Blood Cells Nutrition and You, 2e © 2012 Pearson Education, Inc Anemic Red Blood Cells Nutrition and You, 2e © 2012 Pearson Education, Inc Iron Overload/Iron Toxicity  Too much iron from supplements can cause constipation, nausea, vomiting, diarrhea  Leading cause of accidental poisoning deaths in children under years  Iron overload can damage heart, kidneys, liver, nervous system  Hemochromatosis, a genetic disorder of excess iron absorption can cause iron overload Nutrition and You, 2e © 2012 Pearson Education, Inc Zinc  Acts as a cofactor for more than 100 enzymes  Functions:  DNA synthesis, growth, and development  Healthy immune system and wound healing  Taste acuity  May reduce risk of age-related macular degeneration  Daily needs:  Men: 11 mg/day; women: mg/day  Vegetarians may need as much as 50 percent more Nutrition and You, 2e © 2012 Pearson Education, Inc Zinc Food sources:  Red meat, some seafood, whole grains Too much or too little:  UL = 40 mg/day  As little as 50 mg can cause stomach pains, nausea, vomiting, diarrhea  60 mg/day can inhibit copper absorption  Excessive amounts can suppress immune system, lower HDL cholesterol  Deficiency: hair loss, impaired taste, loss of appetite, diarrhea, delayed sexual maturation, impotence, skin rashes, impaired growth Nutrition and You, 2e © 2012 Pearson Education, Inc Zinc Sources and Physical Needs Food Source Zinc Nutrition and You, 2e © 2012 Pearson Education, Inc Fluoride Functions:  Strengthens tooth enamel against dental caries  Helps repair enamel eroded by acids from bacteria  Reduces amount of acid bacteria produce  Strengthens bones  Fluoridated drinking water has reduced dental caries in United States Daily needs:  Men: 3.8 mg/day; women: 3.1 mg/day Nutrition and You, 2e © 2012 Pearson Education, Inc Fluoride Sources: Foods are not a good source  Fluoridated drinking water and beverages made with this water Too much or too little:  Too little increases risk of dental caries  Too much can cause fluorosis (mottling/staining) when teeth are forming during infancy/childhood  Fluorosis of bones can occur when >10 mg/day is consumed for 10 or more years  UL adults = 10 mg/day, much lower for infants and children Nutrition and You, 2e © 2012 Pearson Education, Inc Iodine  Needed to make essential thyroid hormones  Thyroid hormones regulate metabolic rate; help heart, nerves, muscle and intestines function properly  Daily needs: adults: 150 µg/day  Food sources:  Salt-water fish and seafood  Iodized salt  Amount in foods depends on iodine content of soil, water, fertilizer Nutrition and You, 2e © 2012 Pearson Education, Inc Iodine  Too much or too little: UL = 1,100 µg/day  Excess iodine can impair thyroid function, decrease synthesis and release of thyroid hormones  Early sign of deficiency = goiter (enlarged thyroid gland)  Mandatory iodization of salt has decreased iodine deficiency in United States but not in other parts of world  Iodine deficiency during early stages of fetal development can cause cretinism (congenital hypothyroidism) Nutrition and You, 2e © 2012 Pearson Education, Inc Iodine Sources and Physical Needs Food Source Iodine Nutrition and You, 2e © 2012 Pearson Education, Inc Table 8.2.1 Nutrition and You, 2e © 2012 Pearson Education, Inc Table 8.2.2 Nutrition and You, 2e © 2012 Pearson Education, Inc [...]... Your Daily Water Needs Figure 8. 8 Nutrition and You, 2e © 2012 Pearson Education, Inc Think Before You Drink: Can Water Boost Your Brain? Nutrition and You, 2e © 2012 Pearson Education, Inc Benefits of An Adequate Water Intake  Decreased risk of  Kidney stone formation  Bladder cancer  Colon cancer  Breast cancer? Nutrition and You, 2e © 2012 Pearson Education, Inc Signs of Adequate Water Intake... magnesium and zinc  Form the mineral comes in  Heme versus non-heme iron  Competition with other minerals  Excess zinc can interfere with copper absorption  Body’s need for the mineral Nutrition and You, 2e © 2012 Pearson Education, Inc Classification of Minerals  Major minerals (macrominerals): needed in amounts >100 µg/day  Trace minerals (microminerals): needed in amounts
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