NUT 1004 Water and Minerals Lecture Notes PDF

1 Water and Minerals Kemar Bundy MSc., MPH, PhD(c) NUT 1004 University of Technology, Jamaica ll Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior written...

1 Water and Minerals Kemar Bundy MSc., MPH, PhD(c) NUT 1004 University of Technology, Jamaica ll Education. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or further distribution permitted without the prior written consent of McGraw-H  Learning Outcomes Classify mineral nutrients as major, trace, or possible essential minerals. Explain the difference between a major mineral and a trace mineral. Discuss the functions of water in the body, as well as typical sources of intake and loss. Identify foods that have high and low water content. Discuss how the body maintains its water balance. Explain why dehydration and water intoxication can be life-threatening conditions. Identify general functions of minerals in the body. Discuss factors that influence the body’s ability to absorb and use minerals and retention of minerals during food preparation.  Learning Outcomes List key functions and good food sources of the major mineral nutrients. Discuss deficiency and toxicity disorders associated with the major minerals. Discuss ways to improve intakes of major minerals without relying on dietary supplements. List key functions and good food sources of trace minerals. Discuss deficiency and toxicity disorders associated with the trace minerals. Human aging is the process of water loss 90% 80% 70% 50~60% Water is an important part of the human body!  Water Needs no digestion and is easily absorbed Makes up 50 to 75% of body weight Not a source of energy Simple Diffusion ©McGraw-Hill Education  Functions of Water in the Body ©McGraw-Hill Education 7 Body Water Distribution Intracellular water: Water inside the cells; approximately 2/3 of body water is intracellular Extracellular water: Water surrounding the cells or in the fluid portion of blood (plasma) ©McGraw-Hill Education Body Water Distribution Balance between intra- and extracellular fluids is maintained by concentration of ions, particularly sodium, potassium, chloride, and phosphate ions. Electrolytes: ions that conduct electricity See Table 9.3 for a list of ions. ©McGraw-Hill Education  Sources of Water in the Body Total Water Intake: Includes water in beverages & foods Water weight of fruits and vegetables typically ranges from 60 to 95%. Water Metabolic formed Water : by cells as a metabolic by-product Typical daily water intake = daily water lost by body (output) Average is approximately 2.6 quarts/day ©McGraw-Hill Education  Kidneys and Hydration Kidneys Major regulator of body’s water content & ion concentrations Maintain proper hydration by filtering excess ions from the blood Remove excess ions, including sodium, in urine Water is the main component of urine. Remove drugs & metabolic wastes. Urea— waste product of protein metabolism Kidney stones—may form as a result of inadequate water intake ©McGraw-Hill Education  Water Conservation Diuretics are substances that increase urine output. Caffeine & alcohol Water conservation protects against dehydration. Involves hormones Hormonal Communication ©McGraw-Hill Education  Dehydration 1 Dehydration is body water depletion. Can be caused by restricting fluid intake or profuse sweating, or a combination Severe dehydration is a life-threatening condition. Water is a critically important nutrient. ©McGraw-Hill Education  Dehydration Rapid weight loss is a sign of dehydration because it represents fluid loss. Body fluid loss Symptom/condition 1 to 2% Fatigue and thirst 4% Loss of muscular strength and endurance 7 to 10% Severe weakness 20% Coma & Death ©McGraw-Hill Education  Minerals: Basic Concepts Elements in Earth’s rock, soil, and natural water sources About 15 mineral elements are essential nutrients. Classified as micronutrients because they are required in mg or mcg amounts (See Table 9.1.) Many physiological roles, including: Structural components of tissues Fluid balance Cofactors for chemical reactions ©McGraw-Hill Education  Classifying Essential Minerals Major minerals are essential mineral elements required in amounts of 100 mg or more per day. Trace minerals are essential mineral elements required in amounts that are less than 100 mg per day. Possible essential minerals: Scientists have not fully determined their roles in the body. See Table 9.1. ©McGraw-Hill Education ©McGraw-Hill Education 18  What are Functions of Minerals? ©McGraw-Hill Education ©Purestock/SuperStock  MyPlate: Food Sources of Minerals ©McGraw-Hill Education Source: U.S. Dept. of Agriculture Mango, Kale, and Cereal: ©Stockbyte/Getty Images RF; Milk: ©Ingram Publishing RF; Sardines: ©Caspar Benson/G  Calcium (Ca) The most plentiful mineral in the human body Functions include: Bone formation and maintenance Muscle contraction Blood clot formation Nerve impulse transmission Cell metabolism Fluid milk, yogurt, & cheese supply most of the calcium in Americans’ diets. (See Table 9.6) Healthy adults absorb approximately 30% of calcium in foods: Absorption increases during growth. Absorption decreases as a result of many factors, including advanced age and vitamin D deficiency ©McGraw-Hill Education  Food source of Calcium ©McGraw-Hill Education 23  Maintaining Normal Blood Calcium Levels Thyroid gland: Secretes calcitonin when blood calcium is high Stimulates osteoblasts Calcium uptake by bone tissue Calcium Levels in Blood Parathyroid glands: Secrete parathyroid hormone (PTH) when blood calcium is too low Stimulates osteoclasts to tear down bone Calcium is released into bloodstream. Stimulates kidneys to reduce calcium elimination Stimulates GI tract to absorb more calcium ©McGraw-Hill Education Controlling Blood Calcium Levels ***Vitamin D3 (Calcitriol) is required in this process ©McGraw-Hill Education  Calcium Deficiency Osteoporosis Chronic disease characterized by low bone mass and reduced bone structure. Bone fractures easily. Calcium is a “nutrient of public health concern.” Osteoporosis ©McGraw-Hill Education Reducing the Risk of Osteoporosis Focus on maximizing bone mass while young: Proper diet Follow MyPlate recommendations Vitamin D and calcium intakes Regular exercise Weight-bearing exercise strengthens bones. Avoid smoking Eat less meat, desserts, fried foods, alcohol, and sweetened beverages ©McGraw-Hill Education ©McGraw-Hill Education  Calcium Toxicity UL = 2.0 - 2.5 g/d Hypercalcemia Kidney stones Calcification of soft tissue Interfere with absorption of other minerals ©McGraw-Hill Education  Sodium (Na) Table salt = sodium + chloride 1 tsp salt supplies 2325 mg sodium Salt added to restaurant and processed foods are major sources of sodium in Jamaicans’ diets. Major Functions: positively Why is sodiumcharged ion in extracellular fluid necessary? Conducts nerve impulses Involved in transporting glucose and amino acids into cells Normal muscle function ©McGraw-Hill Education  Food source of Sodium ©McGraw-Hill Education 4 Sodium Deficiency and Toxicity Deficiency: May occur when > 2 to 3% of body weight is lost through diarrhea, vomiting Toxicity: UL = 2300 mg/day Average intake is approximately 3400 mg/day High sodium intakes associated with increased risk of hypertension Dietary Guidelines recommend limiting sodium intake to less than 2300 mg/day. ©McGraw-Hill Education  Hypertension the body hangs on to sodium because *ALDOSTERONE SAVES SODIUM* which leads to increased water retention (i.e. circulating blood volume) which increases blood pressure.  Potassium (K) Functions: Why is potassium necessary? Major positively charged ion in intracellular fluid Needed for nerve impulses, contracting muscles, and kidney function Potassium-rich diets may reduce blood pressure. Dietary Adequacy: AI = 4700 mg/day UL: None from dietary sources Most Americans consume approximately 2700 mg/day. According to the Dietary Guidelines, potassium is a “nutrient of public health concern.” ©McGraw-Hill Education  Food source of Potassium ©McGraw-Hill Education 7 Potassium Deficiency and Excess Deficiency Hypokalemia Life-threatening: weakness, fatigue, irregular heartbeat (impairs heart’s ability to pump blood) Higher risk for those taking diuretics, with GI impairment, eat disorders, alcoholics, athletes Increase blood pressure and risk of stroke Increase risk of kidney stones and bone loss Excess Hyperkalemia Life-threatening Rare in healthy individuals (kidneys readily excrete excess potassium) Higher risk for those with Impaired kidney function ©McGraw-Hill Education DASH Diet (Dietary Approaches to Stop Hypertension) ©McGraw-Hill Education  Magnesium (Mg) Participates in >300 chemical reactions. Roles in the body include: Regulation of muscle and nerve function Maintenance of strong bones Strengthening the immune system Mg is in the chemical structure of chlorophyll. Plant foods are the richest sources of the mineral. Deficiency: Weakness, muscle pain, poor heart function, seizures Toxicity: Diarrhea, weakness, nausea, and malaise in people with kidney failure ©McGraw-Hill Education  Food source of Magnesium ©McGraw-Hill Education 11  Iron (Fe) Iron is a component of hemoglobin and myoglobin. Hemoglobin — iron-containing protein in RBC that transports oxygen to tissues and some CO2 away from tissues Myoglobin — iron-containing protein in muscle cells that controls oxygen uptake from RBC Iron is involved in releasing energy from macronutrients and immune function. Heme iron and non heme iron Heme iron is better absorbed. ©McGraw-Hill Education  Food source of Iron ©McGraw-Hill Education 13  Absorption and Conservation of Iron Digestive tract absorbs 5-15% of iron. Only approximately 5% of iron from enriched grains is absorbed. Intestinal absorption increases when need for the mineral increases. Most iron is stored as ferritin in the liver. Body breaks down dead RBCs and their hemoglobin Iron from broken down hemoglobin is “recycled” and incorporated into new hemoglobin for new RBCs. ©McGraw-Hill Education  Dietary Adequacy RDA Men = 8 mg/day Average intake for American men is 16.6 mg/day. Women (19 to 50 yr. of age) = 18 mg/day iron Most females in this age group have low intakes. Average intake is 12.6 mg/day. Young women are at risk of iron deficiency. Poor iron intake Regular loss of blood ©McGraw-Hill Education  Iron Deficiency-Related Disorders Iron deficiency: Body iron stores are low. Interferes with normal growth, behavior, immune function, cardiac function, and energy metabolism Can lead to iron-deficiency anemia Iron deficiency anemia: Lack of hemoglobin in RBCs; poor oxygen transport In the U.S., iron deficiency is the most common nutritional deficiency. Dangerous for pregnant women and children Iron is a “nutrient of public health concern” for pregnant females. ©McGraw-Hill Education  Iron Toxicity and Overload Iron toxicity: Upper Limit (UL) = 45 mg/day May occur in young children due to accidental supplement overdose. Signs include vomiting and diarrhea, progressing to coma and death. Hereditary hemochromatosis: Common hereditary disorder resulting in excess iron absorption. Joint pain, bronze skin color, diabetes, organ damage ©McGraw-Hill Education  Iodine (I) ©McGraw-Hill Education Iodine Requirements  Plant foods provide iodine if soil contains iodine - Varies region to region  Iodized salt not typically used in processed foods  Bioavailability decreased by goitrogens: - Raw turnips, cabbage, Brussels sprouts, cauliflower, broccoli, rutabagas, potatoes, cassava, peanuts, soy, peaches, strawberries Required for normal thyroid function and production of thyroid hormone ©McGraw-Hill Education  Iodine Functions Vital Role in thyroid hormones, Metabolic Rate, macronutrien metabolism, Growth, Brain and Nervous System Developme thyroxine (T4) triiodothyronine (T3) ©McGraw-Hill Education  Iodine Deficiency Goiter: Characterized by enlarged thyroid gland Low metabolic rate Fatigue Difficulty concentrating on tasks Weight gain Common before advent of iodized salt in areas where iodine content of soil was poor Cretinism: Irreversible condition affecting infants born to women who were iodine deficient during pregnancy ©McGraw-Hill Education  Iodine Toxicity UL = 1100 mg/day ©McGraw-Hill Education ©McGraw-Hill Education 23  Summary of the Major Minerals Mineral Major Functions AI / RDA Dietary Sources Deficiency Toxicity Symptoms Symptoms Sodium Major positive ion of the Table salt, processed Muscle cramps, Contributes to extracellular fluid, aids foods, condiments,headache, nausea, hypertension in nerve impulse transmission sauces, soups, chipsvomiting, fatigue susceptible individuals, and muscle contraction, increases calcium loss in water balance, aids glucose urine; Upper Level is and amino acid absorption 2300 mg PotassiumMajor positive ion of Many fruits and Hypokalemia = Hyperkalemia = Slowing intracellular fluid, aids vegetables, milk and Irregular heartbeat,of the heartbeat, as nerve impulse transmission milk products, meat, loss of appetite, seen in kidney failure and muscle contraction, legumes, whole muscle cramps, water balance grains increased risk of hypertension and stroke Calcium Bone and tooth structure, Milk and milk Increased risk of May cause kidney blood clotting, aids in nerve products, canned osteoporosis stones and other impulse transmission, fish, leafy problems in susceptible muscle contractions, vegetables, tofu, people; Upper Level is enzyme regulation fortified foods 2500 mg Magnesium Involved in 300+ enzymes Wheat bran, green Weakness, muscle Diarrhea, weakness, that use ATP. Stabilizes ATP vegetables, nuts, pain, poor heart nausea, and malaise in → needed for bone chocolate, legumes function, seizures people wit formation, enzyme failure function, nerve and heart function ©McGraw-Hill Education  Thank you ©McGraw-Hill Education