FCNS 201 SECTION HUMAN NUTRITION CHAPTER WATER AND MINERALS Joan Quinn, MEd., RD, LD LEARNING OBJECTIVES Discuss the major roles of water in the body and the amount of water needed by adults Describe how the body regulates water intake and excretion to maintain water balance LEARNING OBJECTIVES, cont Compare the arguments for and against drinking bottled water Explain the role of minerals in maintaining the body’s fluid and electrolyte balance LEARNING OBJECTIVES, cont List the major roles and important deficiency and toxicity symptoms for each major and trace mineral List good food sources for the major and trace minerals MINERAL TRIVIA 4% of adult weight is mineral There are 21 essential known minerals, including copper, zinc, and of course iron Body tolerances vary widely, with some minerals having very narrow lines between deficiency and toxicity MINERAL CLASSIFICATION Major Minerals Trace Minerals ♦ Calcium ♦ Phosphorus ♦ Magnesium ♦ Sodium ♦ Potassium ♦ Chloride ♦ Sulfur ♦ Iron ♦ Iodine ♦ Zinc ♦ Copper ♦ Selenium ♦ Chromium ♦ Fluoride GENERAL MINERAL FUNCTIONS Acid Base Balance Cofactors in enzyme reactions Components of essential body compounds-blood, bone Water balance Transmission of nerve impulses Regulation of muscle contractions Growth Bioavailability Not all ingested minerals can be fully absorbed Animal products are better absorbed ♦ Fiber Mineral interactions ♦ Mineral-Mineral interactions ♦ Vitamin-mineral interactions ♦ Mineral toxicities Toxicity of Minerals Trace minerals Usually through supplementation Risk of contamination Deficiency of Magnesium Irritability Convulsion Irregular heart beat Weakness and disorientation Body stores it readily Deficiency develops slowly Excessive diuretic and alcohol use, heavy perspiration, diarrhea and vomiting Toxicity of Magnesium Uncommon Associated with kidney disorder Overuse of magnesium containing mediations (antacids, laxatives) Weakness, nausea, malaise Elderly at risk Upper Level is 350 mg/day (nonfood source) FUNCTIONS OF SODIUM Major extracellular ion Maintains osmotic pressure Acid-base balance Nerve impulses and muscle contractions Essential for absorption of glucose and other nutrients SODIUM REQUIREMENTS No RDA As little as 500 mg needed Estimated safe and adequate ♦ 1,100 to 3,300 mg/day ♦ Average American diet yields 4-7g/day or more Daily Value is 2,400 mg per day Intake > 2gm can increase urinary calcium loss SODIUM FOOD SOURCES Naturally occurring ♦ Milk, celery, eggs Added in processing ♦ Ham, sauerkraut, sardines, pickles Also consider that added in cooking, and the table, and to the water supply SODIUM, cont Deficiency and excesses ♦ Generally not a concern since kidneys can readily adapt ♦ Most of the concern is in relation to clinical diagnosis ✔ Hypertension ✔ Kidney and liver disease “Salt Sensitive” 10%-15% of adults are High sodium intake leads to high blood pressure Recommend 2-3 gm sodium per day Recommended for all individual Adapt to a low-sodium diet FUNCTIONS OF POTASSIUM Major intercellular ion Maintenance of osmotic pressure Energy release Acid base balance Nerve transmission Acts with mg for muscle relaxation Associated with lowering blood pressure Deficiency and Toxicity Deficiency ♦ Rare ♦ Use of diuretics ♦ Alcoholics, anorexia nervosa, bulimia nervosa ✔ Loss of appetite, muscle cramps, confusion, constipation, irregular heart beat-possible death Toxicity ♦ Kidney disease ♦ Excess potassium builds up in the blood when kidney function is impaired ✔ Can cause heart problems-must be monitored POTASSIUM FOOD SOURCES Fresh fruits and vegetables ♦ Cantaloupe ♦ Potatoes ♦ Bananas ♦ Milk ♦ Broccoli ♦ Oranges ♦ Bananas Milk, Grains, Meats, Dried beans Potassium Requirement Minimum requirement is 2000 mg/day Typical intake is > 2000 mg/day! Chloride Negative ion for the extracellular fluid Components of hydrochloric acid (HCl), immune response, nerve function Excess is excreted by the kidneys/perspiration Minimum requirement is 700 mg/day Much is obtained from salt consumption May also cause high blood pressure CHLORIDE (HCL) Functions ♦ Helps maintain stomach acidity ♦ Acid base balance Sources ♦ Salt …NACL ♦ Processed foods ♦ Clorinated water ✔ ✔ ✔ DV-3400 mg Minimum-750 Average Intake-4.5 grams Sulfur Component of amino acid and vitamins Acid-base balance ♦ Part of a natural diet, primarily from protein ♦ Used to preserve foods