Major Minerals and Water Jamie Pope, Steven Nizielski, and Alison McCook NUTRITION for a Changing World FIRST EDITION Chapter 13 Major Minerals and Water Potassium Power © 2016 by W. H. Freeman and Company & Scientific American

Chapter 13 Objectives Identify the major minerals that have structural functions in the body Discuss the role of calcium in bone health and the consequences of inadequate intake Describe factors that may influence the bioavailability of minerals in the body Identify the major minerals that serve as electrolytes, and describe their role in fluid balance Describe the effect that dietary sodium and potassium have on blood pressure Identify primary sources of calcium, sodium, potassium, and magnesium in the diet Identify at least five functions of water in the body Identify the sources of water for the body and the ways water is lost from the body Describe how antidiuretic hormones regulate water balance

Diets Low in Sodium Could reduce the risk of hypertension Lewis K. Dahl conducted pioneering research on the relationship between sodium and hypertension. Rats that were fed high-sodium diets had increased high blood pressure. Rats that were fed high-potassium diets had lower blood pressure.

Overview of Minerals Major minerals Trace minerals Requirement greater than 100 mg/day Trace minerals Requirement less than 100 mg/day

Overview of Minerals Diverse regulatory and structural functions Many act with enzymes as cofactors Have an electric charge and are, therefore, ions

Major Minerals Sodium Potassium Chloride Calcium Magnesium Phosphorus Sulfur

Trace Minerals Iron Zinc Copper Iodine Selenium Molybdenum Fluoride Manganese Chromium

Mineral Absorption and Bioavailability Bioavailability affected by Deficiency in a mineral Increased need for a mineral Binders: Phytates – Whole cereal grain Oxylates – Found in Spinach and some vegetables Polyphenols – Present in coffee and tea Minerals – Can limit bioavailability by chemically binding to minerals

Minerals in Food Tap water Plants Animal foods Hard water contains calcium and magnesium Soft water contains sodium Plants Reflect mineral content of the soil Animal foods Processed and refined foods Whole, unprocessed foods Processing tends to reduce mineral content. Although cooking doesn’t destroy minerals, boiling can leach minerals into cooking water.

Structural Roles in the Body Bone formation and maintenance Calcium Magnesium Phosphorus

Calcium (Ca) Most abundant mineral in the body Functions 99% in bone and teeth 1% in body cells and fluids Functions Strengthening bone and teeth Blood clotting Hormone secretion Muscle contraction Nerve transmission

Calcium Homeostasis When calcium levels fall Parathyroid gland releases parathyroid hormone (PTH) PTH stimulates production of active vitamin D Increases calcium absorption in the intestine PTH and activated vitamin D mobilize calcium from the bone and decrease calcium excretion from the kidneys

Bone Remodeling

Dietary Sources of Calcium AI = 1,000 mg/day for adults 19 to 50 years of age

Calcium Deficiency

Calcium Toxicity Upper tolerable intake level (UL) is 2,500 mg Constipation Interference with iron absorption Hypercalcemia

Magnesium (Mg) Function Cofactor in more than 300 chemical reactions 50% to 60% is found in bones Role in the transport of ions across cell membranes for muscle contraction, nerve impulse conduction, and maintaining heart rhythm Involved in extracting energy from carbohydrates, proteins, and fats Role in protein production Necessary in activating vitamin D Bone health

Dietary Sources of Magnesium

Magnesium Deficiency Kidneys will excrete less and body will absorb more Osteoporosis Increases the risk for Atherosclerosis Cancer Diabetes Hypertension

Magnesium Toxicity Rare from diet Toxicity from supplement misuse does occur

Phosphorus (P) In every cell of the body Function Component of bone and cartilage, phospholipids, DNA, and RNA Involved in energy metabolism Regulates many enzymes Helps maintain acid-base balance

Phosphorus (P) Deficiency Overconsumption Rare, as found in protein-rich foods and food additives Overconsumption Increased levels associated with cardiovascular disease, particularly in people with kidney disease

Sulfur (S) Component of protein Present in thiamin and biotin Present in cysteine and methionine Present in thiamin and biotin Deficiency unknown Toxicity rare Excrete excess in the urine

Maintaining Fluid Balance in the Body Electrolytes: sodium, potassium, chloride Maintain fluid balance Transmit nerve impulses Muscle contraction Transport nutrients

Sodium (Na) Major positively charged ion in extracellular fluids Functions Regulating fluid balance Regulating blood pressure Transmitting nerve impulses Contracting muscles Helping nutrient transport

Sodium Consumption AI = 1,500 mg/day Food sources: table salt and processed foods UL for adults = 2,300 mg/day Overconsumption can cause hypertension

DASH Diet Dietary Approaches to Stop Hypertension (DASH) Helps lower sodium intake and increases potassium, calcium, and magnesium intake

DASH Diet

Potassium (K) Primary electrolyte within cells Functions Regulating fluid balance Acting as a cofactor for certain enzymes Helping nutrient transport Helping maintain electrical activity of the heart May counter effects of excess sodium on blood pressure

Dietary Sources of Potassium

Potassium Deficiency Mild forms Severe depletion causes hypokalemia Increase risk of hypertension, stroke, and heart attacks Severe depletion causes hypokalemia Usually from excessive fluid loss through vomiting, diarrhea, use of diuretics, or kidney disorders Fatigue Muscle weakness Abnormal heart rhythms Increased calcium excretion Reduced insulin production

Potassium Toxicity Only from supplement misuse Symptoms Low heart rate Abnormal heart rhythm Supplementation should be prescribed and monitored by a health-care provider

Chloride (Cl) Half of the mineral composition of table salt (NaCl) Found primarily in extracellular fluids Involved in fluid balance Half of hydrochloric acid (HCl) Abundant in the diet with sodium Overconsumption increases blood pressure

Water (H20) Functions Regulates body temperature Transports nutrients and oxygen Lubricates joints Present in mucus and saliva Cushions tissues Acts as a solvent Removes waste

Water Balance in the Body 2/3 of water is intracellular 1/3 of water is extracellular Waters moves by osmosis Based on the concentration of solutes

Water Balance

Antidiuretic Hormone and Water Balance

Water Intake Recommendations

Water Intake Deficiency Excess water consumption without electrolytes Dehydration Nausea Dizziness Elevated temperature Excess water consumption without electrolytes Hyponatremia Confusion Nausea Vomiting Bloating Swelling around the brain

Summary 16 essential minerals in the diet are inorganic elements supplied through food Minerals in the diet are classified as major or trace, based on the amount required per day; major minerals include sodium, potassium, chloride, calcium, magnesium, phosphorus, and sulfur Minerals have diverse regulatory and structural functions in the human body, including participation in chemical reactions, transmission of nerve impulses, maintenance of fluid balance, and support of the immune system Bioavailability of the minerals we consume is affected by various factors, including nutritional status as well as the presence of binders, other minerals, and certain vitamins

Summary (Cont’d) Sodium, potassium, and chloride are electrolytes that function in fluid balance, transmission of nerve impulses, and muscle contraction Dietary intakes of sodium and potassium affect our risk of hypertension Dietary Approaches to Stop Hypertension (DASH) diet includes strategies to reduce sodium intake and increase intake of foods rich in potassium, calcium, and magnesium Calcium levels in the blood are regulated through a process called calcium homeostasis Adequate calcium intake across the lifespan is important in the maintenance of bone density and the prevention of osteoporosis

Summary (Cont’d) Water is an essential nutrient with critical roles in the body; among its many functions, water helps regulate body temperature, transports nutrients and oxygen to tissues, lubricates joints and mucous membranes, cushions tissues, and removes waste Water makes up the greatest percentage of our body, both by weight and by volume, and is present in varying amounts in every tissue and organ To maintain water balance in the body, intake of fluid from beverages, food, and water produced in metabolism must equal water output from urine, respiration, perspiration, and stools Consuming inadequate or excess amounts of water can lead to health issues